'00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Hi All,

'00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
EXCEPT: cold starts will result in about 10 seconds of roughness, enough
to cause a little bit of wobble to the body.. It runs rough about long
enough after starting to: put on the seatbelt, check behind me in the
mirror and adjust the radio.. After that it is butter smooth.

Oil pressure runs about 50 at highway speeds about 20 at idle.

Runs great other than this. Warm starts (even after a couple of hours
while the internal engine is warm are fine --)

Any ideas? I'm new to Jeep.

Thanks in advance

Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.

First off, are you under the 7-70 powertrain warantee? If so, take it
to the dealer.

The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
or gunk in the throttle body.

look here.
http://members.cox.net/wilsond/tb/tb.html

It could also be a sensor reading poorly, but before we go there check/clean
the throttle body.

--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.

First off, are you under the 7-70 powertrain warantee? If so, take it
to the dealer.

The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
or gunk in the throttle body.

look here.
http://members.cox.net/wilsond/tb/tb.html

It could also be a sensor reading poorly, but before we go there check/clean
the throttle body.

--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.

First off, are you under the 7-70 powertrain warantee? If so, take it
to the dealer.

The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
or gunk in the throttle body.

look here.
http://members.cox.net/wilsond/tb/tb.html

It could also be a sensor reading poorly, but before we go there check/clean
the throttle body.

--
-- DougW -- 93 ZJ 4.0 http://members.cox.net/wilsond
HESCO Supercharger - 300W IASCA Stereo - Edelbrock IAS Shocks
Gibson Exhaust - rear DCpower - custom gauge install - Stillen Rotors

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Doug,

Is it best to remove the TB to clean this, or can it be done by spraying
down the slot from the top?

In article <3572c.35550$1k.34221@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
>
> First off, are you under the 7-70 powertrain warantee? If so, take it
> to the dealer.
>
> The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
> or gunk in the throttle body.
>
> look here.
> http://members.cox.net/wilsond/tb/tb.html
>
> It could also be a sensor reading poorly, but before we go there check/clean
> the throttle body.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Doug,

Is it best to remove the TB to clean this, or can it be done by spraying
down the slot from the top?

In article <3572c.35550$1k.34221@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
>
> First off, are you under the 7-70 powertrain warantee? If so, take it
> to the dealer.
>
> The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
> or gunk in the throttle body.
>
> look here.
> http://members.cox.net/wilsond/tb/tb.html
>
> It could also be a sensor reading poorly, but before we go there check/clean
> the throttle body.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Doug,

Is it best to remove the TB to clean this, or can it be done by spraying
down the slot from the top?

In article <3572c.35550$1k.34221@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
>
> First off, are you under the 7-70 powertrain warantee? If so, take it
> to the dealer.
>
> The primary cause of a rough idle is a clogged IAP (Idle Air Passage)
> or gunk in the throttle body.
>
> look here.
> http://members.cox.net/wilsond/tb/tb.html
>
> It could also be a sensor reading poorly, but before we go there check/clean
> the throttle body.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Have over thirty on your spark plugs?
http://www.----------.com/lubeschedule.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Marc wrote:
>
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.
>
> Thanks in advance
>
> Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Have over thirty on your spark plugs?
http://www.----------.com/lubeschedule.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Marc wrote:
>
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.
>
> Thanks in advance
>
> Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Have over thirty on your spark plugs?
http://www.----------.com/lubeschedule.pdf
God Bless America, ßill O|||||||O
mailto:--------------------

Marc wrote:
>
> Hi All,
>
> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> to cause a little bit of wobble to the body.. It runs rough about long
> enough after starting to: put on the seatbelt, check behind me in the
> mirror and adjust the radio.. After that it is butter smooth.
>
> Oil pressure runs about 50 at highway speeds about 20 at idle.
>
> Runs great other than this. Warm starts (even after a couple of hours
> while the internal engine is warm are fine --)
>
> Any ideas? I'm new to Jeep.
>
> Thanks in advance
>
> Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Yes, forgot to include that, changed the plugs.. It doesn't cause
extended cranking times or anything, just a fairly rough idle for about
10 seconds then she's fine. No smoke (blue white or black) from the
tailpipe either..) Cleaned the TB. After that first 10 seconds it
pretty well idles butter-smooth. Power and response are great on the
road too.



In article <404901FF.D6AC9DD7@cox.net>, ----------@cox.net says...
> Have over thirty on your spark plugs?
> http://www.----------.com/lubeschedule.pdf
> God Bless America, ßill O|||||||O
> mailto:--------------------
>
> Marc wrote:
> >
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
> >
> > Thanks in advance
> >
> > Marc
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Yes, forgot to include that, changed the plugs.. It doesn't cause
extended cranking times or anything, just a fairly rough idle for about
10 seconds then she's fine. No smoke (blue white or black) from the
tailpipe either..) Cleaned the TB. After that first 10 seconds it
pretty well idles butter-smooth. Power and response are great on the
road too.



In article <404901FF.D6AC9DD7@cox.net>, ----------@cox.net says...
> Have over thirty on your spark plugs?
> http://www.----------.com/lubeschedule.pdf
> God Bless America, ßill O|||||||O
> mailto:--------------------
>
> Marc wrote:
> >
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
> >
> > Thanks in advance
> >
> > Marc
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Yes, forgot to include that, changed the plugs.. It doesn't cause
extended cranking times or anything, just a fairly rough idle for about
10 seconds then she's fine. No smoke (blue white or black) from the
tailpipe either..) Cleaned the TB. After that first 10 seconds it
pretty well idles butter-smooth. Power and response are great on the
road too.



In article <404901FF.D6AC9DD7@cox.net>, ----------@cox.net says...
> Have over thirty on your spark plugs?
> http://www.----------.com/lubeschedule.pdf
> God Bless America, ßill O|||||||O
> mailto:--------------------
>
> Marc wrote:
> >
> > Hi All,
> >
> > '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
> > EXCEPT: cold starts will result in about 10 seconds of roughness, enough
> > to cause a little bit of wobble to the body.. It runs rough about long
> > enough after starting to: put on the seatbelt, check behind me in the
> > mirror and adjust the radio.. After that it is butter smooth.
> >
> > Oil pressure runs about 50 at highway speeds about 20 at idle.
> >
> > Runs great other than this. Warm starts (even after a couple of hours
> > while the internal engine is warm are fine --)
> >
> > Any ideas? I'm new to Jeep.
> >
> > Thanks in advance
> >
> > Marc
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Doug,
>
> Is it best to remove the TB to clean this, or can it be done by spraying
> down the slot from the top?

It's easier to just spray the slot. That TB was off since it was replaced
with a larger bore when I supercharged. (it's sitting in the garage
and still dirty) :)

You can remove it though. You can also pull the IAC solenoid off, but usually
spraying with the engine running is enough. Then use a paper towel with
cleaner and wipe under the butterfly. (an old toothbrush also works well)

If you pull the TB, remember those screws holding it down only get torqued
to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Doug,
>
> Is it best to remove the TB to clean this, or can it be done by spraying
> down the slot from the top?

It's easier to just spray the slot. That TB was off since it was replaced
with a larger bore when I supercharged. (it's sitting in the garage
and still dirty) :)

You can remove it though. You can also pull the IAC solenoid off, but usually
spraying with the engine running is enough. Then use a paper towel with
cleaner and wipe under the butterfly. (an old toothbrush also works well)

If you pull the TB, remember those screws holding it down only get torqued
to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Doug,
>
> Is it best to remove the TB to clean this, or can it be done by spraying
> down the slot from the top?

It's easier to just spray the slot. That TB was off since it was replaced
with a larger bore when I supercharged. (it's sitting in the garage
and still dirty) :)

You can remove it though. You can also pull the IAC solenoid off, but usually
spraying with the engine running is enough. Then use a paper towel with
cleaner and wipe under the butterfly. (an old toothbrush also works well)

If you pull the TB, remember those screws holding it down only get torqued
to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Ok, just got back in from spraying down that slot, wiped down.. I did
call the local jeep dealer and there is an issue "rough idle at cold
start" that is addressed in a PCM update. I'm hoping that this might
be it, or spraying down that slot. FWIW, that TB was pretty dirty
yesterday when I took the small brush to it; now it's almost shiny.

The dealer mentioned about carbon buildup on the back of the valves;
that it might be absorbing the first few moments of fuel sprayed in. .
I think that if the first squirts of fuel were getting absorbed by the
carbon that I'd get extended cranking time most likely..? He mentioned
to use some chevron techron concentrate in a full tank and see if that
helps, which I have some of that already waiting to use actually.

Marc


In article <2E72c.35556$1k.34393@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Doug,
> >
> > Is it best to remove the TB to clean this, or can it be done by spraying
> > down the slot from the top?
>
> It's easier to just spray the slot. That TB was off since it was replaced
> with a larger bore when I supercharged. (it's sitting in the garage
> and still dirty) :)
>
> You can remove it though. You can also pull the IAC solenoid off, but usually
> spraying with the engine running is enough. Then use a paper towel with
> cleaner and wipe under the butterfly. (an old toothbrush also works well)
>
> If you pull the TB, remember those screws holding it down only get torqued
> to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
> on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Ok, just got back in from spraying down that slot, wiped down.. I did
call the local jeep dealer and there is an issue "rough idle at cold
start" that is addressed in a PCM update. I'm hoping that this might
be it, or spraying down that slot. FWIW, that TB was pretty dirty
yesterday when I took the small brush to it; now it's almost shiny.

The dealer mentioned about carbon buildup on the back of the valves;
that it might be absorbing the first few moments of fuel sprayed in. .
I think that if the first squirts of fuel were getting absorbed by the
carbon that I'd get extended cranking time most likely..? He mentioned
to use some chevron techron concentrate in a full tank and see if that
helps, which I have some of that already waiting to use actually.

Marc


In article <2E72c.35556$1k.34393@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Doug,
> >
> > Is it best to remove the TB to clean this, or can it be done by spraying
> > down the slot from the top?
>
> It's easier to just spray the slot. That TB was off since it was replaced
> with a larger bore when I supercharged. (it's sitting in the garage
> and still dirty) :)
>
> You can remove it though. You can also pull the IAC solenoid off, but usually
> spraying with the engine running is enough. Then use a paper towel with
> cleaner and wipe under the butterfly. (an old toothbrush also works well)
>
> If you pull the TB, remember those screws holding it down only get torqued
> to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
> on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Ok, just got back in from spraying down that slot, wiped down.. I did
call the local jeep dealer and there is an issue "rough idle at cold
start" that is addressed in a PCM update. I'm hoping that this might
be it, or spraying down that slot. FWIW, that TB was pretty dirty
yesterday when I took the small brush to it; now it's almost shiny.

The dealer mentioned about carbon buildup on the back of the valves;
that it might be absorbing the first few moments of fuel sprayed in. .
I think that if the first squirts of fuel were getting absorbed by the
carbon that I'd get extended cranking time most likely..? He mentioned
to use some chevron techron concentrate in a full tank and see if that
helps, which I have some of that already waiting to use actually.

Marc


In article <2E72c.35556$1k.34393@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Doug,
> >
> > Is it best to remove the TB to clean this, or can it be done by spraying
> > down the slot from the top?
>
> It's easier to just spray the slot. That TB was off since it was replaced
> with a larger bore when I supercharged. (it's sitting in the garage
> and still dirty) :)
>
> You can remove it though. You can also pull the IAC solenoid off, but usually
> spraying with the engine running is enough. Then use a paper towel with
> cleaner and wipe under the butterfly. (an old toothbrush also works well)
>
> If you pull the TB, remember those screws holding it down only get torqued
> to 32 in.lbs (that's inch lbs) (2.6 ft.lbs) You can put way more than that
> on with just a nut driver. finger tight + 1/4 turn is a "close" estimate.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Yes, forgot to include that, changed the plugs.. It doesn't cause
> extended cranking times or anything, just a fairly rough idle for about
> 10 seconds then she's fine. No smoke (blue white or black) from the
> tailpipe either..) Cleaned the TB. After that first 10 seconds it
> pretty well idles butter-smooth. Power and response are great on the
> road too.

Did this just happen after your last tank of gas or has it been going
on longer. Might try adding a bottle of fuel injector cleaner with
water disperser (gunk or valvoline) with the next fillup, and try a
different station.

Other causes are sensors or vac leaks that seal with expansion,
the warmup loop is fairly forgiving and bad sensors will cause
rough idle even after warmup.

Start the motor and spray some TB cleaner around the base of the
TB. listen for any RPM change.

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Yes, forgot to include that, changed the plugs.. It doesn't cause
> extended cranking times or anything, just a fairly rough idle for about
> 10 seconds then she's fine. No smoke (blue white or black) from the
> tailpipe either..) Cleaned the TB. After that first 10 seconds it
> pretty well idles butter-smooth. Power and response are great on the
> road too.

Did this just happen after your last tank of gas or has it been going
on longer. Might try adding a bottle of fuel injector cleaner with
water disperser (gunk or valvoline) with the next fillup, and try a
different station.

Other causes are sensors or vac leaks that seal with expansion,
the warmup loop is fairly forgiving and bad sensors will cause
rough idle even after warmup.

Start the motor and spray some TB cleaner around the base of the
TB. listen for any RPM change.

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Yes, forgot to include that, changed the plugs.. It doesn't cause
> extended cranking times or anything, just a fairly rough idle for about
> 10 seconds then she's fine. No smoke (blue white or black) from the
> tailpipe either..) Cleaned the TB. After that first 10 seconds it
> pretty well idles butter-smooth. Power and response are great on the
> road too.

Did this just happen after your last tank of gas or has it been going
on longer. Might try adding a bottle of fuel injector cleaner with
water disperser (gunk or valvoline) with the next fillup, and try a
different station.

Other causes are sensors or vac leaks that seal with expansion,
the warmup loop is fairly forgiving and bad sensors will cause
rough idle even after warmup.

Start the motor and spray some TB cleaner around the base of the
TB. listen for any RPM change.

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Ok, just got back in from spraying down that slot, wiped down.. I did
> call the local jeep dealer and there is an issue "rough idle at cold
> start" that is addressed in a PCM update. I'm hoping that this might
> be it, or spraying down that slot. FWIW, that TB was pretty dirty
> yesterday when I took the small brush to it; now it's almost shiny.

Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
If it was real nasty you might benefit from removing the IAC (four antitamper torx
screws) And cleaning the guts.

Before you do that, disconnect the hearness from the TB (IAC and TPS) then
reconnect. They might be a bit corroded. Every once in a while I disconnect,
clean, and apply some dilectric grease to the sensor connectors.

> The dealer mentioned about carbon buildup on the back of the valves;
> that it might be absorbing the first few moments of fuel sprayed in. .
> I think that if the first squirts of fuel were getting absorbed by the
> carbon that I'd get extended cranking time most likely..?

Yep. Generally the fuel is atomized by the injectors before it even gets
to the valve. A dripping injector will cause buildup but it will also cause
a hellaciously rough idle.

> He mentioned
> to use some chevron techron concentrate in a full tank and see if that
> helps, which I have some of that already waiting to use actually.

See my other post. Doing that every year is a good thing. When you use
a fuel injector cleaner read to make sure it is safe for O2 and catalytic
converters. Also look for one that says to use it every 3000 miles or so.
The ones for use with every tank are generally too weak to clean anything.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Ok, just got back in from spraying down that slot, wiped down.. I did
> call the local jeep dealer and there is an issue "rough idle at cold
> start" that is addressed in a PCM update. I'm hoping that this might
> be it, or spraying down that slot. FWIW, that TB was pretty dirty
> yesterday when I took the small brush to it; now it's almost shiny.

Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
If it was real nasty you might benefit from removing the IAC (four antitamper torx
screws) And cleaning the guts.

Before you do that, disconnect the hearness from the TB (IAC and TPS) then
reconnect. They might be a bit corroded. Every once in a while I disconnect,
clean, and apply some dilectric grease to the sensor connectors.

> The dealer mentioned about carbon buildup on the back of the valves;
> that it might be absorbing the first few moments of fuel sprayed in. .
> I think that if the first squirts of fuel were getting absorbed by the
> carbon that I'd get extended cranking time most likely..?

Yep. Generally the fuel is atomized by the injectors before it even gets
to the valve. A dripping injector will cause buildup but it will also cause
a hellaciously rough idle.

> He mentioned
> to use some chevron techron concentrate in a full tank and see if that
> helps, which I have some of that already waiting to use actually.

See my other post. Doing that every year is a good thing. When you use
a fuel injector cleaner read to make sure it is safe for O2 and catalytic
converters. Also look for one that says to use it every 3000 miles or so.
The ones for use with every tank are generally too weak to clean anything.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Marc did pass the time by typing:
> Ok, just got back in from spraying down that slot, wiped down.. I did
> call the local jeep dealer and there is an issue "rough idle at cold
> start" that is addressed in a PCM update. I'm hoping that this might
> be it, or spraying down that slot. FWIW, that TB was pretty dirty
> yesterday when I took the small brush to it; now it's almost shiny.

Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
If it was real nasty you might benefit from removing the IAC (four antitamper torx
screws) And cleaning the guts.

Before you do that, disconnect the hearness from the TB (IAC and TPS) then
reconnect. They might be a bit corroded. Every once in a while I disconnect,
clean, and apply some dilectric grease to the sensor connectors.

> The dealer mentioned about carbon buildup on the back of the valves;
> that it might be absorbing the first few moments of fuel sprayed in. .
> I think that if the first squirts of fuel were getting absorbed by the
> carbon that I'd get extended cranking time most likely..?

Yep. Generally the fuel is atomized by the injectors before it even gets
to the valve. A dripping injector will cause buildup but it will also cause
a hellaciously rough idle.

> He mentioned
> to use some chevron techron concentrate in a full tank and see if that
> helps, which I have some of that already waiting to use actually.

See my other post. Doing that every year is a good thing. When you use
a fuel injector cleaner read to make sure it is safe for O2 and catalytic
converters. Also look for one that says to use it every 3000 miles or so.
The ones for use with every tank are generally too weak to clean anything.

--
DougW

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Carbon deposits on the back side of the intake valves will cause this
concern, and Techron will likely eliminate it. Very good product, does what
it says it will.

GM has a little trouble with cold misfires in some engine families.
Engineering has traced the cause to these deposits. They put out a bulletin
and actually recommended Techron by name. I have found that it fixes these
sorts of problems nearly 100% of the time.

The deposits we are talking about are like a sponge. Atomized fuel flows
past the top of the valve and into the cylinder, but this sponge-action
actually absorbs a miniscule amount of the fuel on cold start, causing lean
misfire. Once the sponge becomes saturated with fuel, the misfire
disappears.


Jerry


"DougW" <post.replies@invalid.address> wrote in message
news:pc82c.35561$1k.35001@okepread01...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.
>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Carbon deposits on the back side of the intake valves will cause this
concern, and Techron will likely eliminate it. Very good product, does what
it says it will.

GM has a little trouble with cold misfires in some engine families.
Engineering has traced the cause to these deposits. They put out a bulletin
and actually recommended Techron by name. I have found that it fixes these
sorts of problems nearly 100% of the time.

The deposits we are talking about are like a sponge. Atomized fuel flows
past the top of the valve and into the cylinder, but this sponge-action
actually absorbs a miniscule amount of the fuel on cold start, causing lean
misfire. Once the sponge becomes saturated with fuel, the misfire
disappears.


Jerry


"DougW" <post.replies@invalid.address> wrote in message
news:pc82c.35561$1k.35001@okepread01...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.
>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

Carbon deposits on the back side of the intake valves will cause this
concern, and Techron will likely eliminate it. Very good product, does what
it says it will.

GM has a little trouble with cold misfires in some engine families.
Engineering has traced the cause to these deposits. They put out a bulletin
and actually recommended Techron by name. I have found that it fixes these
sorts of problems nearly 100% of the time.

The deposits we are talking about are like a sponge. Atomized fuel flows
past the top of the valve and into the cylinder, but this sponge-action
actually absorbs a miniscule amount of the fuel on cold start, causing lean
misfire. Once the sponge becomes saturated with fuel, the misfire
disappears.


Jerry


"DougW" <post.replies@invalid.address> wrote in message
news:pc82c.35561$1k.35001@okepread01...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.
>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <oj82c.35562$1k.6979@okepread01>,
>
> Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
> If it was real nasty you might benefit from removing the IAC (four antitamper torx
> screws) And cleaning the guts.

Sounds like a plan.. I have a Haynes manual and what I'd consider a
pretty good understanding of under the hood (thanks Dad). Have the
appt. for next Thursday for that PCM flash.



>
> Before you do that, disconnect the hearness from the TB (IAC and TPS) then
> reconnect. They might be a bit corroded. Every once in a while I disconnect,
> clean, and apply some dilectric grease to the sensor connectors.


Check. I'll get that tomorrow too.


>
> Yep. Generally the fuel is atomized by the injectors before it even gets
> to the valve. A dripping injector will cause buildup but it will also cause
> a hellaciously rough idle.


Idle is butter smooth after about 10 seconds. The engine always lights
up within 2 seconds of turning the key, hot or cold.

>
> > He mentioned
> > to use some chevron techron concentrate in a full tank and see if that
> > helps, which I have some of that already waiting to use actually.
>
> See my other post. Doing that every year is a good thing. When you use
> a fuel injector cleaner read to make sure it is safe for O2 and catalytic
> converters. Also look for one that says to use it every 3000 miles or so.
> The ones for use with every tank are generally too weak to clean anything.

Yup, every 3000 right on the bottle. I will change the oil in about
400 miles, so I'll dump that in the fuel on Monday.


I'll check those connections and all this weekend and report back.

thanks!

Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <oj82c.35562$1k.6979@okepread01>,
>
> Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
> If it was real nasty you might benefit from removing the IAC (four antitamper torx
> screws) And cleaning the guts.

Sounds like a plan.. I have a Haynes manual and what I'd consider a
pretty good understanding of under the hood (thanks Dad). Have the
appt. for next Thursday for that PCM flash.



>
> Before you do that, disconnect the hearness from the TB (IAC and TPS) then
> reconnect. They might be a bit corroded. Every once in a while I disconnect,
> clean, and apply some dilectric grease to the sensor connectors.


Check. I'll get that tomorrow too.


>
> Yep. Generally the fuel is atomized by the injectors before it even gets
> to the valve. A dripping injector will cause buildup but it will also cause
> a hellaciously rough idle.


Idle is butter smooth after about 10 seconds. The engine always lights
up within 2 seconds of turning the key, hot or cold.

>
> > He mentioned
> > to use some chevron techron concentrate in a full tank and see if that
> > helps, which I have some of that already waiting to use actually.
>
> See my other post. Doing that every year is a good thing. When you use
> a fuel injector cleaner read to make sure it is safe for O2 and catalytic
> converters. Also look for one that says to use it every 3000 miles or so.
> The ones for use with every tank are generally too weak to clean anything.

Yup, every 3000 right on the bottle. I will change the oil in about
400 miles, so I'll dump that in the fuel on Monday.


I'll check those connections and all this weekend and report back.

thanks!

Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <oj82c.35562$1k.6979@okepread01>,
>
> Gets nasty doesn't it. Go for the PCM update it might be a programming problem.
> If it was real nasty you might benefit from removing the IAC (four antitamper torx
> screws) And cleaning the guts.

Sounds like a plan.. I have a Haynes manual and what I'd consider a
pretty good understanding of under the hood (thanks Dad). Have the
appt. for next Thursday for that PCM flash.



>
> Before you do that, disconnect the hearness from the TB (IAC and TPS) then
> reconnect. They might be a bit corroded. Every once in a while I disconnect,
> clean, and apply some dilectric grease to the sensor connectors.


Check. I'll get that tomorrow too.


>
> Yep. Generally the fuel is atomized by the injectors before it even gets
> to the valve. A dripping injector will cause buildup but it will also cause
> a hellaciously rough idle.


Idle is butter smooth after about 10 seconds. The engine always lights
up within 2 seconds of turning the key, hot or cold.

>
> > He mentioned
> > to use some chevron techron concentrate in a full tank and see if that
> > helps, which I have some of that already waiting to use actually.
>
> See my other post. Doing that every year is a good thing. When you use
> a fuel injector cleaner read to make sure it is safe for O2 and catalytic
> converters. Also look for one that says to use it every 3000 miles or so.
> The ones for use with every tank are generally too weak to clean anything.

Yup, every 3000 right on the bottle. I will change the oil in about
400 miles, so I'll dump that in the fuel on Monday.


I'll check those connections and all this weekend and report back.

thanks!

Marc

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <pc82c.35561$1k.35001@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.

It's been since I got it, about 10 days ago, but it was going on most
likely before that. When I test drove it someone else had just come
back with it, so I got it with a warm engine. Otherwise cosmetically
it is perfect and after that cold start it runs beautifully.

Just rather disconcerting to get an initial idle rough enough to jostle
the vehicle for a number of seconds till it levels out..

I'll check your other suggestions this weekend and report back..

thanks
Marc


>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <pc82c.35561$1k.35001@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.

It's been since I got it, about 10 days ago, but it was going on most
likely before that. When I test drove it someone else had just come
back with it, so I got it with a warm engine. Otherwise cosmetically
it is perfect and after that cold start it runs beautifully.

Just rather disconcerting to get an initial idle rough enough to jostle
the vehicle for a number of seconds till it levels out..

I'll check your other suggestions this weekend and report back..

thanks
Marc


>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

In article <pc82c.35561$1k.35001@okepread01>,
post.replies@invalid.address says...
> Marc did pass the time by typing:
> > Yes, forgot to include that, changed the plugs.. It doesn't cause
> > extended cranking times or anything, just a fairly rough idle for about
> > 10 seconds then she's fine. No smoke (blue white or black) from the
> > tailpipe either..) Cleaned the TB. After that first 10 seconds it
> > pretty well idles butter-smooth. Power and response are great on the
> > road too.
>
> Did this just happen after your last tank of gas or has it been going
> on longer. Might try adding a bottle of fuel injector cleaner with
> water disperser (gunk or valvoline) with the next fillup, and try a
> different station.

It's been since I got it, about 10 days ago, but it was going on most
likely before that. When I test drove it someone else had just come
back with it, so I got it with a warm engine. Otherwise cosmetically
it is perfect and after that cold start it runs beautifully.

Just rather disconcerting to get an initial idle rough enough to jostle
the vehicle for a number of seconds till it levels out..

I'll check your other suggestions this weekend and report back..

thanks
Marc


>
> Other causes are sensors or vac leaks that seal with expansion,
> the warmup loop is fairly forgiving and bad sensors will cause
> rough idle even after warmup.
>
> Start the motor and spray some TB cleaner around the base of the
> TB. listen for any RPM change.
>
>
>
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

I have a bottle of techron concentrate (up to 20 gallons treatment),
that I picked up at Target for $4.84 (on clearance I think), so I plan
to load up the tank this weekend with it.

Hoping that between the techron and the pcm update, one of them will get
it. What kind of time frame would I be looking at to see if the techron
is making a difference? The whole tank run through, 100 miles, etc?

Marc



In article <40491f98_2@newspeer2.tds.net>, "Jerry Newton"
<figatmcttelecom.com> says...
> Carbon deposits on the back side of the intake valves will cause this
> concern, and Techron will likely eliminate it. Very good product, does what
> it says it will.
>
> GM has a little trouble with cold misfires in some engine families.
> Engineering has traced the cause to these deposits. They put out a bulletin
> and actually recommended Techron by name. I have found that it fixes these
> sorts of problems nearly 100% of the time.
>
> The deposits we are talking about are like a sponge. Atomized fuel flows
> past the top of the valve and into the cylinder, but this sponge-action
> actually absorbs a miniscule amount of the fuel on cold start, causing lean
> misfire. Once the sponge becomes saturated with fuel, the misfire
> disappears.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

I have a bottle of techron concentrate (up to 20 gallons treatment),
that I picked up at Target for $4.84 (on clearance I think), so I plan
to load up the tank this weekend with it.

Hoping that between the techron and the pcm update, one of them will get
it. What kind of time frame would I be looking at to see if the techron
is making a difference? The whole tank run through, 100 miles, etc?

Marc



In article <40491f98_2@newspeer2.tds.net>, "Jerry Newton"
<figatmcttelecom.com> says...
> Carbon deposits on the back side of the intake valves will cause this
> concern, and Techron will likely eliminate it. Very good product, does what
> it says it will.
>
> GM has a little trouble with cold misfires in some engine families.
> Engineering has traced the cause to these deposits. They put out a bulletin
> and actually recommended Techron by name. I have found that it fixes these
> sorts of problems nearly 100% of the time.
>
> The deposits we are talking about are like a sponge. Atomized fuel flows
> past the top of the valve and into the cylinder, but this sponge-action
> actually absorbs a miniscule amount of the fuel on cold start, causing lean
> misfire. Once the sponge becomes saturated with fuel, the misfire
> disappears.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

I have a bottle of techron concentrate (up to 20 gallons treatment),
that I picked up at Target for $4.84 (on clearance I think), so I plan
to load up the tank this weekend with it.

Hoping that between the techron and the pcm update, one of them will get
it. What kind of time frame would I be looking at to see if the techron
is making a difference? The whole tank run through, 100 miles, etc?

Marc



In article <40491f98_2@newspeer2.tds.net>, "Jerry Newton"
<figatmcttelecom.com> says...
> Carbon deposits on the back side of the intake valves will cause this
> concern, and Techron will likely eliminate it. Very good product, does what
> it says it will.
>
> GM has a little trouble with cold misfires in some engine families.
> Engineering has traced the cause to these deposits. They put out a bulletin
> and actually recommended Techron by name. I have found that it fixes these
> sorts of problems nearly 100% of the time.
>
> The deposits we are talking about are like a sponge. Atomized fuel flows
> past the top of the valve and into the cylinder, but this sponge-action
> actually absorbs a miniscule amount of the fuel on cold start, causing lean
> misfire. Once the sponge becomes saturated with fuel, the misfire
> disappears.
>
>

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

"Marc" <none@all.com> wrote in message
news:MPG.1ab2b8906514b426989685@netnews.mchsi.com. ..

>>> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
EXCEPT: cold starts will result in about 10 seconds of roughness<<<

My 96 4.0 which now has 82k on it has done just that since the day I drove
it off the show room floor. Like yours it's a tad rough for the first few
seconds (half block) then levels out. I just figured it was the nature of
the beast.

The only thing that I've had to do other than brakes, plugs and normal
maintenance in 82k was to replace
something in the steering column called a "clock spring" (don't have a clue
what it does) and that was done while it was still in warranty. RM~

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

"Marc" <none@all.com> wrote in message
news:MPG.1ab2b8906514b426989685@netnews.mchsi.com. ..

>>> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
EXCEPT: cold starts will result in about 10 seconds of roughness<<<

My 96 4.0 which now has 82k on it has done just that since the day I drove
it off the show room floor. Like yours it's a tad rough for the first few
seconds (half block) then levels out. I just figured it was the nature of
the beast.

The only thing that I've had to do other than brakes, plugs and normal
maintenance in 82k was to replace
something in the steering column called a "clock spring" (don't have a clue
what it does) and that was done while it was still in warranty. RM~

Re: '00 XJ 4.0L - First start when cold problem ---- Please Read..
 

"Marc" <none@all.com> wrote in message
news:MPG.1ab2b8906514b426989685@netnews.mchsi.com. ..

>>> '00 Cherokee XJ with 4.0L, 48k miles. Runs perfectly in every way
EXCEPT: cold starts will result in about 10 seconds of roughness<<<

My 96 4.0 which now has 82k on it has done just that since the day I drove
it off the show room floor. Like yours it's a tad rough for the first few
seconds (half block) then levels out. I just figured it was the nature of
the beast.

The only thing that I've had to do other than brakes, plugs and normal
maintenance in 82k was to replace
something in the steering column called a "clock spring" (don't have a clue
what it does) and that was done while it was still in warranty. RM~