93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

This thread details this beast what I've done, and still outstanding issues:
http://www.carkb.com/Uwe/Forum.aspx/...c293b518dbauwe


but simply put: 210K mi's, just had a tune up and it idles low, ~600-620.

Monday noon drove it about 35 highway miles home (~72mph, hit 80-85 a couple
times), parked it for 6 hours, ran it for two short 5 minute trips parked it
until Wednesday, 2PM.

7/8 tank of gas in it, it started right up, then shut right down. 4 times.
5th and 6th time I tried pumping the pedal a couple times before the start
which made no differnce. 7th time I held the pedal to about 2K rpm's for ~15
secs, then eased off over the next 10 seconds and when I let go-- it shut.

It was as if it had no idle at all.

Several minutes later (after fiddling with the plug wires by pushing down on
them firmly, on both ends) I tried to 2 more times (in the manner of the very
1st attempt) and it just shut.

I decided to try one more time like time #7 before calling a tow, and this
time, it stayed running-- with the normal (for this car) idle.

10 minute discussion with my mechanic led to the possibiltiy of IAC-- which I
cleaned very well only a few weeks ago. Could the IAC get "stuck", perhaps be
going bad? I postulated the fuel pump (bad pressure perhaps-- which could
also be the source of my low idle).

Any thoughts?

Thanks.

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

My thoughts are that a stuck or going bad IAC is a good guess. I am in
principle against swapping components "blindly", but if the IAC doesn't cost
too much then you can't go too far wrong replacing it. I would probably
remove and thoroughly clean the throttle body, replacing the base gasket of
course, because it's easy and then you eliminate that as a potential
problem.

Earle

"jimboe via CarKB.com" <u15312@uwe> wrote in message
news:5a3b1aa6026ba@uwe...
> This thread details this beast what I've done, and still outstanding
issues:
>
http://www.carkb.com/Uwe/Forum.aspx/...c293b518dbauwe
>
>
> but simply put: 210K mi's, just had a tune up and it idles low, ~600-620.
>
> Monday noon drove it about 35 highway miles home (~72mph, hit 80-85 a
couple
> times), parked it for 6 hours, ran it for two short 5 minute trips parked
it
> until Wednesday, 2PM.
>
> 7/8 tank of gas in it, it started right up, then shut right down. 4 times.
> 5th and 6th time I tried pumping the pedal a couple times before the start
> which made no differnce. 7th time I held the pedal to about 2K rpm's for
~15
> secs, then eased off over the next 10 seconds and when I let go-- it shut.
>
> It was as if it had no idle at all.
>
> Several minutes later (after fiddling with the plug wires by pushing down
on
> them firmly, on both ends) I tried to 2 more times (in the manner of the
very
> 1st attempt) and it just shut.
>
> I decided to try one more time like time #7 before calling a tow, and this
> time, it stayed running-- with the normal (for this car) idle.
>
> 10 minute discussion with my mechanic led to the possibiltiy of IAC--
which I
> cleaned very well only a few weeks ago. Could the IAC get "stuck", perhaps
be
> going bad? I postulated the fuel pump (bad pressure perhaps-- which could
> also be the source of my low idle).
>
> Any thoughts?
>
> Thanks.
>
> --
> Message posted via CarKB.com
> http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

My thoughts are that a stuck or going bad IAC is a good guess. I am in
principle against swapping components "blindly", but if the IAC doesn't cost
too much then you can't go too far wrong replacing it. I would probably
remove and thoroughly clean the throttle body, replacing the base gasket of
course, because it's easy and then you eliminate that as a potential
problem.

Earle

"jimboe via CarKB.com" <u15312@uwe> wrote in message
news:5a3b1aa6026ba@uwe...
> This thread details this beast what I've done, and still outstanding
issues:
>
http://www.carkb.com/Uwe/Forum.aspx/...c293b518dbauwe
>
>
> but simply put: 210K mi's, just had a tune up and it idles low, ~600-620.
>
> Monday noon drove it about 35 highway miles home (~72mph, hit 80-85 a
couple
> times), parked it for 6 hours, ran it for two short 5 minute trips parked
it
> until Wednesday, 2PM.
>
> 7/8 tank of gas in it, it started right up, then shut right down. 4 times.
> 5th and 6th time I tried pumping the pedal a couple times before the start
> which made no differnce. 7th time I held the pedal to about 2K rpm's for
~15
> secs, then eased off over the next 10 seconds and when I let go-- it shut.
>
> It was as if it had no idle at all.
>
> Several minutes later (after fiddling with the plug wires by pushing down
on
> them firmly, on both ends) I tried to 2 more times (in the manner of the
very
> 1st attempt) and it just shut.
>
> I decided to try one more time like time #7 before calling a tow, and this
> time, it stayed running-- with the normal (for this car) idle.
>
> 10 minute discussion with my mechanic led to the possibiltiy of IAC--
which I
> cleaned very well only a few weeks ago. Could the IAC get "stuck", perhaps
be
> going bad? I postulated the fuel pump (bad pressure perhaps-- which could
> also be the source of my low idle).
>
> Any thoughts?
>
> Thanks.
>
> --
> Message posted via CarKB.com
> http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

My thoughts are that a stuck or going bad IAC is a good guess. I am in
principle against swapping components "blindly", but if the IAC doesn't cost
too much then you can't go too far wrong replacing it. I would probably
remove and thoroughly clean the throttle body, replacing the base gasket of
course, because it's easy and then you eliminate that as a potential
problem.

Earle

"jimboe via CarKB.com" <u15312@uwe> wrote in message
news:5a3b1aa6026ba@uwe...
> This thread details this beast what I've done, and still outstanding
issues:
>
http://www.carkb.com/Uwe/Forum.aspx/...c293b518dbauwe
>
>
> but simply put: 210K mi's, just had a tune up and it idles low, ~600-620.
>
> Monday noon drove it about 35 highway miles home (~72mph, hit 80-85 a
couple
> times), parked it for 6 hours, ran it for two short 5 minute trips parked
it
> until Wednesday, 2PM.
>
> 7/8 tank of gas in it, it started right up, then shut right down. 4 times.
> 5th and 6th time I tried pumping the pedal a couple times before the start
> which made no differnce. 7th time I held the pedal to about 2K rpm's for
~15
> secs, then eased off over the next 10 seconds and when I let go-- it shut.
>
> It was as if it had no idle at all.
>
> Several minutes later (after fiddling with the plug wires by pushing down
on
> them firmly, on both ends) I tried to 2 more times (in the manner of the
very
> 1st attempt) and it just shut.
>
> I decided to try one more time like time #7 before calling a tow, and this
> time, it stayed running-- with the normal (for this car) idle.
>
> 10 minute discussion with my mechanic led to the possibiltiy of IAC--
which I
> cleaned very well only a few weeks ago. Could the IAC get "stuck", perhaps
be
> going bad? I postulated the fuel pump (bad pressure perhaps-- which could
> also be the source of my low idle).
>
> Any thoughts?
>
> Thanks.
>
> --
> Message posted via CarKB.com
> http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Earle Horton did pass the time by typing:
> My thoughts are that a stuck or going bad IAC is a good guess. I am in
> principle against swapping components "blindly", but if the IAC doesn't cost
> too much then you can't go too far wrong replacing it. I would probably
> remove and thoroughly clean the throttle body, replacing the base gasket of
> course, because it's easy and then you eliminate that as a potential
> problem.

You can pull the connector off the IAC while the vehicle is running.
All that does is eliminate the ECUs ability to control RPM but
the engine will settle down.

That will tell you if it's causing the problem. But not entirely.
A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
into making poor adjustments.

Keep in mind it's a stepper motor. If the harness ground or any of
the wires are bad, the motor will be erratic.

If you do take it off, NEVER try to start the car with the solinoid
exposed or the little pintle will go flying and your then stuck with
getting a new IAC.

Do a quick check of the vac hoses. Especially the one running to the
brake booster. Clamp it off and see if that helps.
--
DougW

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Earle Horton did pass the time by typing:
> My thoughts are that a stuck or going bad IAC is a good guess. I am in
> principle against swapping components "blindly", but if the IAC doesn't cost
> too much then you can't go too far wrong replacing it. I would probably
> remove and thoroughly clean the throttle body, replacing the base gasket of
> course, because it's easy and then you eliminate that as a potential
> problem.

You can pull the connector off the IAC while the vehicle is running.
All that does is eliminate the ECUs ability to control RPM but
the engine will settle down.

That will tell you if it's causing the problem. But not entirely.
A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
into making poor adjustments.

Keep in mind it's a stepper motor. If the harness ground or any of
the wires are bad, the motor will be erratic.

If you do take it off, NEVER try to start the car with the solinoid
exposed or the little pintle will go flying and your then stuck with
getting a new IAC.

Do a quick check of the vac hoses. Especially the one running to the
brake booster. Clamp it off and see if that helps.
--
DougW

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Earle Horton did pass the time by typing:
> My thoughts are that a stuck or going bad IAC is a good guess. I am in
> principle against swapping components "blindly", but if the IAC doesn't cost
> too much then you can't go too far wrong replacing it. I would probably
> remove and thoroughly clean the throttle body, replacing the base gasket of
> course, because it's easy and then you eliminate that as a potential
> problem.

You can pull the connector off the IAC while the vehicle is running.
All that does is eliminate the ECUs ability to control RPM but
the engine will settle down.

That will tell you if it's causing the problem. But not entirely.
A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
into making poor adjustments.

Keep in mind it's a stepper motor. If the harness ground or any of
the wires are bad, the motor will be erratic.

If you do take it off, NEVER try to start the car with the solinoid
exposed or the little pintle will go flying and your then stuck with
getting a new IAC.

Do a quick check of the vac hoses. Especially the one running to the
brake booster. Clamp it off and see if that helps.
--
DougW

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Thanks for the tips Gentlemen, I will try some of them this weekend.

Since that incident Wednesday, the truck has not had any problem starting.

Jim

DougW wrote:
>Earle Horton did pass the time by typing:
>> My thoughts are that a stuck or going bad IAC is a good guess. I am in
>> principle against swapping components "blindly", but if the IAC doesn't cost
>> too much then you can't go too far wrong replacing it. I would probably
>> remove and thoroughly clean the throttle body, replacing the base gasket of
>> course, because it's easy and then you eliminate that as a potential
>> problem.
>
>You can pull the connector off the IAC while the vehicle is running.
>All that does is eliminate the ECUs ability to control RPM but
>the engine will settle down.
>
>That will tell you if it's causing the problem. But not entirely.
>A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
>into making poor adjustments.
>
>Keep in mind it's a stepper motor. If the harness ground or any of
>the wires are bad, the motor will be erratic.
>
>If you do take it off, NEVER try to start the car with the solinoid
>exposed or the little pintle will go flying and your then stuck with
>getting a new IAC.
>
>Do a quick check of the vac hoses. Especially the one running to the
>brake booster. Clamp it off and see if that helps.

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Thanks for the tips Gentlemen, I will try some of them this weekend.

Since that incident Wednesday, the truck has not had any problem starting.

Jim

DougW wrote:
>Earle Horton did pass the time by typing:
>> My thoughts are that a stuck or going bad IAC is a good guess. I am in
>> principle against swapping components "blindly", but if the IAC doesn't cost
>> too much then you can't go too far wrong replacing it. I would probably
>> remove and thoroughly clean the throttle body, replacing the base gasket of
>> course, because it's easy and then you eliminate that as a potential
>> problem.
>
>You can pull the connector off the IAC while the vehicle is running.
>All that does is eliminate the ECUs ability to control RPM but
>the engine will settle down.
>
>That will tell you if it's causing the problem. But not entirely.
>A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
>into making poor adjustments.
>
>Keep in mind it's a stepper motor. If the harness ground or any of
>the wires are bad, the motor will be erratic.
>
>If you do take it off, NEVER try to start the car with the solinoid
>exposed or the little pintle will go flying and your then stuck with
>getting a new IAC.
>
>Do a quick check of the vac hoses. Especially the one running to the
>brake booster. Clamp it off and see if that helps.

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1

Re: 93 ZJ 5.2 GJC: Difficult start today- any ideas?
 

Thanks for the tips Gentlemen, I will try some of them this weekend.

Since that incident Wednesday, the truck has not had any problem starting.

Jim

DougW wrote:
>Earle Horton did pass the time by typing:
>> My thoughts are that a stuck or going bad IAC is a good guess. I am in
>> principle against swapping components "blindly", but if the IAC doesn't cost
>> too much then you can't go too far wrong replacing it. I would probably
>> remove and thoroughly clean the throttle body, replacing the base gasket of
>> course, because it's easy and then you eliminate that as a potential
>> problem.
>
>You can pull the connector off the IAC while the vehicle is running.
>All that does is eliminate the ECUs ability to control RPM but
>the engine will settle down.
>
>That will tell you if it's causing the problem. But not entirely.
>A bad O2 sensor, intake leak, or dirty wires can still trick the ECU
>into making poor adjustments.
>
>Keep in mind it's a stepper motor. If the harness ground or any of
>the wires are bad, the motor will be erratic.
>
>If you do take it off, NEVER try to start the car with the solinoid
>exposed or the little pintle will go flying and your then stuck with
>getting a new IAC.
>
>Do a quick check of the vac hoses. Especially the one running to the
>brake booster. Clamp it off and see if that helps.

--
Message posted via CarKB.com
http://www.carkb.com/Uwe/Forums.aspx/jeep-cars/200601/1