97 jeep cherrokee problem

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don - 06 Oct 2006 16:31 GMT

was wondering if anyone reading this group may be able to help. I have a
97 jeep grand cherokee limited, 6 cyl. have an intermittent problem:
engine stalls and sometimes can be very difficult to restart. can happen
before reaching operating temp and even after reaching operating temp. the
only error code says multiple misfires. [ as when tring to restart you can
tell, very rough idle, definitely not firing all cylinders correctly]
engine is firing correctly]. my mechanic has replaced the pick up coil in
distributor, ignition coil and air idle speed valve. still having same
problem. he thinks it is the pcm and wants to replace that next. he also
mentioned that the wire harness, in back of the pcm was not in great
condition. quite frankly, I hate when he guesses, already $400 into the fix
already.is there someone who may have had/heard of this problem or is there
a test to see if the pcm is in fact bad?

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Mike Romain - 06 Oct 2006 17:14 GMT

On the Jeep 4.0 engine, the sensor plugs and sockets get corroded
easily. They can usually be fixed by spraying them with an electronic
contact cleaner that electronic stores sell. You can use WD40 in a
pinch, but the real cleaner is best.

The primary one that causes stalls is the CPS's plug and socket. The
CPS is located high on the drivers side of the bell housing. It has
about a foot and a bit of cable then it's plug. I am not sure where the
plug resides on the GC, but you can trace the wires from the bell
housing corner. On some Cherokees the plug sits on top of the manifold,
on others it is on the firewall. Some even have it over on the
passenger side firewall I think.

The second most common one is the TPS, on the throttle body but when it
gets a dirty connection, the rpm usually fluctuates as well as a cold
stall.

I am in the rust belt and also see strange stalls due to the body's
ground strap or cable being corroded and ground theft happening.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)

> was wondering if anyone reading this group may be able to help. I have a
> 97 jeep grand cherokee limited, 6 cyl. have an intermittent problem:
[quoted text clipped - 9 lines]
> already.is there someone who may have had/heard of this problem or is there
> a test to see if the pcm is in fact bad?

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don - 06 Oct 2006 18:09 GMT

Mike-
The CPS was replaced about a year ago, when pulled out it obviously
wasn't gapped correctly as it was worn down by the flywheel. hadn't
thought of this part again as, bad as the old one was, never a problem
with it, only check engine light on to tip off a problem. no check engine
lilght on this time. but is there any test for the PCM that you know of?
haven't seen anything in the hayse repair book,, except that 98 and newer
replacement PCM have to be programmed by the dealer. your thoughts?

> On the Jeep 4.0 engine, the sensor plugs and sockets get corroded
> easily. They can usually be fixed by spraying them with an electronic
[quoted text clipped - 22 lines]
> Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
> (More Off Road album links at bottom of the view page)

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spamTHISbrp@yahoo.com - 06 Oct 2006 17:52 GMT

If you are getting a bunch of black smoke after getting it restarted,
next time try starting it after a stall by cranking the engine with the
throttle wide-open.

Works as good on flooded fuel-injected engines every bit as good as it
worked on carb. engines.

That won't fix the orig. problem, of course.

Dave

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