Started misfiring and oil pressure shot all the way up...

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11-05-2011, 08:44 AM

#16

99KeeSport

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Join Date: Aug 2010

Location: Bennett, CO

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Year: 99

Model: Cherokee

Engine: 4L/6

Quote:

Originally Posted by tjwalker

There are a number of possibilities for stalling, but one of the primary ones is a "marginal" battery. And yes, you CAN have a battery that is strong enough to start the engine, but marginal enough to give the engine management system fits and create "stalling" Have the battery LOAD TESTED. Any parts store will do this for you for free.

It could be something else, but failure to verify the battery early in the troubleshooting process is a mistake.

The battery is only used to start the vehicle. After the vehicle is started, the alternator provides power for charging the battery and for accessories.

Sorry, I just can't see the battery being involved in a stalling issue investigation.

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11-05-2011, 08:48 AM

#17

tjwalker

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Join Date: Nov 2010

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Year: 1999

Model: Cherokee

Engine: 4.0

Quote:

Originally Posted by 99KeeSport

Strongly disagree. The engine mgmt system will NOT work properly with a marginal battery. And stalling is the #1 symptom. If you search this forum and others, you will find a multitude of threads with this exact issue. Here is but one.

https://www.cherokeeforum.com/f2/98-...e-dies-105238/

Ignoring the battery would be unwise. I see it all the time and have been working on 4.0 engines since 1987.

Last edited by tjwalker; 11-05-2011 at 08:54 AM.

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11-06-2011, 12:01 PM

#18

Apostle2

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Year: 2000

Model: Cherokee

Engine: 4.0

Die at idle.

As tj suggest, you should check your battery voltage. After that, take another look at you coil pack. Even though you installed a new coil, take it back off and look at the springs that are inside each spark plug boot. Using some needle nose pliers, reach inside the boot and grab the springs and stretch them so they will extend to the end of the boots. Perform this spring stretch for each coil boot. Smear a thin film of dielectric grease (bulb-grease) on the tip of each spark plug. Then re-install the coil pack to see it helps.

I've installed a couple of new coils that had your same symptoms. The engine would die at idle and no codes were generated, if I increased the RPM's slightly it would not die.

Good Luck