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So my father got a modified 90 wrangler, I believe he bought it with fuel injectors and shortly after started getting issues. He got a new pcm and it fried out almost immediately. Now he got a pcm from a 95 jeep grand cherokee and it starts and then shuts down. Not sure if there's a flash or skim work around as there isn't even a system to read the keys. Any advice would be appreciated
 

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My son had a 91 Wrangler with fuel injection and my daughter had a 91 Cherokee also. Both were fuel injected. My daughters had a Jasper remanufactured engine in it that had almost 40,000 miles left on the warranty. Her jeep had 3 different modes of running,.........excellent, fair & poor. I went through everything I could think of & did a complete tune up with new plugs ,wires, cap, rotor, coil, fuel filter, air filter, and checked the timing and checked for trouble codes,(none). I ruled out injectors because when it ran good, it ran great! It never went away. Had a professional shop diagnose it and they put it on their dyno & even checked for blockage in the converter; again , no soap! Just before we traded it in on a 98 Cherokee, I tried to get a replacement PCM. It turns out that the problem was the vehicle had the wrong one. We found out the change over year was 93. It was wordage in the aftermarket that was the problem. It was supposed to be 91 & up to 93; (not including 93). I checked the info on the unit and sure enough, it was the wrong one. Too late, we had already put a down payment on the used 98 which ran up to 287,000 before she got another one! So, long story short, it may NOT be the problem, but be advised that the year of the unit can make a world of difference.
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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Welcome to Allpar. You must use the correct PCM for the vehicle. Swapping a PCM from a vehicle with the VTSS (security) system can damage a vehicle without the option.
Once VTSS is enabled, it can't be disabled, even at the dealer level. It has to get sent out to an authorized FCA electronic repair depot with proof of ownership.
You will get the start/stall.
There is no feasible work-around. If you could, the car thieves could too.

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There is no skim on a 1995, but a Grand Cherokee would have a security system that shuts the vehicle down when a proper unlock signal (either from a key in the door or a keyless remote) is not received.
Hopefully find a computer from a more basic vehicle will work.
 

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When you said Jeep and computer I had memories of a friend's Grand Cherokee with a 6, probably a 4.0L. It was built during the AMC/Renault years and had a Renix ignition and a Motorola EEC that was in front of the instrument cluster. I seem to recall a crank sensor as it was part of the problem. I think I wound up changing the crank sensor and Renix module, EEC was fine.

Good luck with it!
 

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1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
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I think that around 1990-1991 was the change-over to Chrysler-ized EFI and other electronics.
Before that was the Renix (Renault-Bendix) EFI used on Jeep-Eagle. Very French when we first got them.
There was no fault codes for the Renix system, instead you had to perform a sequence with the DRB2 and the Jeep-Eagle adapter box of pressing the throttle to the floor and then releasing it, starting the engine and revving it to 2K RPM and assorted other things.
At the end of the sequence, you would get a pass/fail banner.
The Renix wasn't a bad system, just unfamiliar and becoming obsolete.

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Thank you all for your expertise on matters like these and thanks for posting the charts in post #3. I was wondering why there is no info on those charts for 1991 & 1992 ??
By the way, my experience was approx. 25 years ago and is to the best of my recollection. We never did get a replacement PCM as there was none available in the aftermarket, temporarily, (at that time) and Chrysler wanted $500.00 for one. My daughter made it easy as she hit a deer with it, not too bad but that was that ! :rolleyes:
 
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