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@***.net>, ----------@***.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
>

 

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@***.net>, ----------@***.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
>

 

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@***.net>, ----------@***.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
>

 

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

 

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

 

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

 

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.
>
>

 

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.
>
>

 

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.
>
>

 

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.