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Testing Ignition Module on 88 XJ

I've got a hot stalling problem on my 88 XJ.

The Jeep runs perfectly most of the time, however after several "hot soaks" (eg, my wife out shopping), or driven for several miles on the freeway with the A/C on the engine just quits while driving down the road.

I first suspected the notorious Crank Position Sensor, which I replaced last week. No joy. Had to have the Jeep towed home last weekend. (Wife not happy).

I've gone over the ALL the connections in the engine compartment, cleaned, inspected and even tightened the female connections on those that looked loose. All the grounds and battery cables have been cleaned.

So now I suspect that the ignition control module is the culprit. Before I spend $150.00 on a replacement I'd like to know if there is a way to test the existing module?

Any advice you could give me would be appreciated.

Dave in Columbus

Reply to
noone
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There is no way to test it short of plugging in a replacement as far as I know.

I had symptoms like yours and also changed the CPS with no joy.

In my case it was a rotted wire mesh cable from the back of the engine head to the firewall. Changed that and no more troubles.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

snipped-for-privacy@yahoo.com wrote:

Reply to
Mike Romain

Reply to
L.W.(ßill)

I just had that happen to me I found a parts store that could test mine I have a 85 XJ 2.8 and a new one was $39 Its been fine for two months now..

85XJ 86XJ 3'lift 85 4x4 chev trk
Reply to
Rich

What flavor of parts store?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's
Reply to
Mike Romain

I know NAPA does the test for free from experience first hand.

Reply to
happy jeeper

Cool, I am going to phone a local one and ask them, thanks.

Mike

happy jeeper wrote:

Reply to
Mike Romain

Actually, some do and some don't. It's best to call around. Our NAPA here charges you unless the module is bad and you buy a new one from them.

Chris

Reply to
c

...

Take a blow dryer (or hot air gun) and heat the module... if you can get it to fail this way, then it is the culprit. Or, take some freeze spray or icewater and cool the module down when it fails next... if this fixes it, then you should replace it. __ Steve .

Reply to
Stephen Cowell

My fuel pump relay used to stop working when it was hot. In the 88 you can just buy all new bosch relays for under the hood. Its cheap and a good idea. the fuel pump relay is over by the battery and dist. cap. KH

Reply to
Kevin in San Diego

Thanks for the suggestions. I did switch the relays around, thinking that the fuel pump relay might be failing when hot. No help there. The Jeep has stalled on me only once and at that time I did check for fuel pump whine when turning on the ignition. Pump seemed to be running.

I think I'll try my heat gun on the module as suggested. Maybe I can get it to fail in my garage so I can pinpoint the problem. I wish it would just fail completely with a cloud of smoke so I'd know exactly what it causing the stalling problem.

The fuel pump, as far as I know is the original. It will probably wait until this winter to fail so I can replace it on my back in twenty degree weather.

Again, thanks for the help!

Reply to
noone

Reply to
bllsht

There isn't a test for the module. Basically, you test everything else, then replace the module. Many of AMC and Renault's diagnostic procedures started off with "Using a known good part..." Not very helpful if you have an intermittent problem that's not present while you're checking it.

One thing you can try is unbolting the module, turning it over and massaging the underside with the engine running. Sometimes you can get them to quit running by doing this, verifying the module is bad.

Reply to
bllsht

Different animal. You're talking about a GM setup with the small module in the distributor. The Renix ign. module used in 88 is on the right fender near the relays and has a coil sitting on it.

Reply to
bllsht

The first one I lost was also an 88 original - after 125k miles. I could hear it run, the pressure looked good before I started but as soon as I cranked it the pressure went to zip - pump couldn't even keep up on start. A cheap fuel pressure tester might save a lot of cussing.

Reply to
Will Honea

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