Tim9368

1998 Grand Cherokee. 2WD. 4.0 Auto Trans 200K miles

Recent parts: Crank sensor, battery, IAC, TPS (as well as lots of suspension components)

All connections to ECM have been cleaned, -re attached with dielectric grease. NO CODES stored.

Truck runs and feels great, but will stall for no apparent reason at low speed/rpm. It will then start right up, most of the time.

Lots of opinions/input point to need for new ECM, but I do not want to throw parts at it, I just want it fixed. It is supposed to be my teenager's ride for work and school, but the stalling (not very often, but too often for comfort) makes me uneasy because of the power steering pump loss when it stalls. Is there a way to test the ECM, or a place where I can pay to get a definitive diagnostic?

This a sweet running truck with a clean interior/exterior and no fluid leaks. the stall thing is driving me batty.

Please help.

Thanks!

-t

jomps

have the battery load tested

tjwalker

Unfortunately, the computer cannot be tested without specialized equipment, which only the companies that deal with computers have at their access.

Although it certainly could be the computer, in the vast majority of cases, these things turn out to be something else.

I don't disagree with load testing the battery to start with. You CAN have a batter strong enough to start the engine, but marginal enough to create stalling. Gotta rule that out.

After that, I would suspect an engine management sensor or possibly the ignition coil. The coil can be subject to "thermal failure (heat related). You may want to try a different coil.

Bustedback

The cam sensor can also have a "thermal failure".

Tim9368

Thanks for your responses, gentlemen.
I just installed a brand new battery - and the problem nearly went away, but not completely.
So moving forward, I should test the CAM sensor and ignition coil?
Does a failure like this fit the symptoms? Remember- if and when it stalls, you turn off the ignition completely, and then it will start right back up.

What are the specs on testing the coil and CAM sensor? When I was troubleshooting a different Jeep last year I was so frustrated, because the tests were inconclusive when there were no symptoms.

Thanks again for your help.

-t

Tim9368

I finally punted on this and took her to a pro. They immediately diagnosed a faulty distributer. Now I have a new one and I hope that was the problem. They ran a full scan and came up with no more information or symptoms. I hope the guy was honest with me - He explained that a bad distributer does not have its own code, because it was a mechanical failure. He also said that this was what was most likely causing my symptoms. I'll update again if the problem reappears, but for now I am hopeful that it is fixed.

-t

tjwalker

He is correct in that a distributor fail will not set a code. If the symptoms are gone, you're good to go.

Troubleshooting is rarely a straight line. Hope it is resolved for you!