Stalling while driving

WhiskeyTango · Apr 12, 2021

Good evening,

While I am still looking for my GC, I have a friend that is having the issue of their GC stalling while driving. After it sits for 10 minutes it'll start up and drive like normal until it happens again. It doesn't throw a code that I know of. It's an '04 GC with the 4.0 310,000 km (192,000 mi). All the connectors into the PCM are tight, grounds are good from what we can tell.

Would anyone have anything else to look for? I looked through the search function, but only found the problems with the ZJ having close to the same symptoms. After looking through mr google and famous youtube "mechanics", most say it's from the pins becoming dislodged from the board. So we are both at a loss and looking for guidance for our jeeping elders

Please and thank you

Brian-Emmons · Apr 12, 2021

on the ZJ 4.0 its the crank position sensor on the fly wheel that gives the problem and normally hits a warm engine, then refuses to start again until cooled down.
If it is the CPS then it will only get worse until it will not start at all.
Yes I have had to change mine

Jaks98zj · Apr 14, 2021

WhiskeyTango said:
Good evening,

While I am still looking for my GC, I have a friend that is having the issue of their GC stalling while driving. After it sits for 10 minutes it'll start up and drive like normal until it happens again. It doesn't throw a code that I know of. It's an '04 GC with the 4.0 310,000 km (192,000 mi). All the connectors into the PCM are tight, grounds are good from what we can tell.

Would anyone have anything else to look for? I looked through the search function, but only found the problems with the ZJ having close to the same symptoms. After looking through mr google and famous youtube "mechanics", most say it's from the pins becoming dislodged from the board. So we are both at a loss and looking for guidance for our jeeping elders

Please and thank you

Try the air idle control valve. It sounds like it might be that.

WhiskeyTango · Apr 15, 2021

Thanks for the replies. The problem is actually on a WJ, so I'm not sure if it'd be the same symptoms. Worst we can do is try it out and see what happens. It's starting to get to where it can only go for about 30 to 40 minutes on the hiway speeds, then it just dies, starts back up again after 20 minutes of sitting. I can't see any frayed/worn wires for where the harness comes close to contacting the head of the block, but then again I wasn't able to get all that far back down on the harness before it couldn't see anything.

mmc780 · Apr 16, 2021

On a different vehicle, I've had an issue where the coil pack will work fine early in a drive but when it gets hot it loses conductivity and craps out. That was more of a misfiring and running like crap but I suppose if ignored for long enough it could cause stalling.
I suppose the same phenomenon could happen to plug wires...

I think its safe to assume its a spark problem because fuel and air are unlikely to be affected by heat, the question is where in the electrical system is the open happening at...I would start with a full ignition system refresh because thats the most highly stressed electrical system...

HumpinmyJeep · Apr 17, 2021

Brian-Emmons said:
on the ZJ 4.0 its the crank position sensor on the fly wheel that gives the problem and normally hits a warm engine, then refuses to start again until cooled down.
If it is the CPS then it will only get worse until it will not start at all.
Yes I have had to change mine

ignition switch

amsd · Apr 21, 2021

mmc780 said:
On a different vehicle, I've had an issue where the coil pack will work fine early in a drive but when it gets hot it loses conductivity and craps out. That was more of a misfiring and running like crap but I suppose if ignored for long enough it could cause stalling.
I suppose the same phenomenon could happen to plug wires...

I think its safe to assume its a spark problem because fuel and air are unlikely to be affected by heat, the question is where in the electrical system is the open happening at...I would start with a full ignition system refresh because thats the most highly stressed electrical system...

Hi

i have changed my Oem coil pack since manufacturer always select
the cheapest parts and did go for Granatelli coils
did not have engine issue but it was not as crisp as i wanted
on pedal input felt that my engine was taking is time to throttle up
my engine run way better have a tiny (very tiny ) bit of improved fuel economy
down side the set of 8 coils set you back about 800$
have no regrets

there is cheap coils available but i would not buy them

my gdma always said
you have to be rich to buy cheap stuff
personally i d rather wait and buy quality stuff

hope i helped
cheers

WhiskeyTango · Apr 22, 2021

Thanks all for the replies and information. Turned out to be a bad CPS and got it all happy again.

Stalling while driving

WhiskeyTango

Brian-Emmons

Jaks98zj

WhiskeyTango

mmc780

HumpinmyJeep

amsd

WhiskeyTango

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