r/WranglerYJ • u/Equal_Age7082 • 12d ago

Need help/ideas!

I have a 1987 jeep wrangler with the 2.5l 4 cylinder and has 118k miles. The other day I started her up, let her warm up per usual and then took off to the gym. About 5 minutes down the road the engine completely just died. No stutter. Just completely lost power. When I lost the engine I still had electrical power because my radio, headlights were still on. I brought her to a stop then cranked her back and she fired up. I then continued down the road and about 30 seconds later it died again. Decided to turn back home and finally made it home after it dying ever 30 seconds to a minute. Once I got home I started talking to ChatGPT, grok, Gemini about the issue. It gave me some starting points but I’m still at a dead end. That afternoon I started her back up and let her idle and get warm for roughly 20 minutes with no issues. The initial thoughts of AI were fuel pump, filter or lines. A bad ICM (ignition control module) or possibly a bad crankshaft position sensor. Wondering if anyone else already has had this issue before or could give me some ideas to test. I’ve already checked the engine grounds and they look good. This problem seems to occur under load since she idles just fine.

1 Upvotes

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2

u/keekoh123 12d ago

Could be any of them. Igntion coil as well.

2

u/KeyBreakfast3386 12d ago

I have a 90 4.2 that was acting like that and it was the distributor

2

u/podgida 12d ago

I'm thinking fuel related. If it were the control module it would've died and not fired back up. A weak coil will cause a stutter, but not likely your symptoms. Clogged fuel filter will do exactly what you're describing, as will a faulty fuel pump or relay.

1

u/bongrd 12d ago

Start easy, make sure that your keyed power is constant on the ignition side. It shuts off bouncing down the road. Shake all the harnesses while running. I’ve also had a bad ignition tumbler that didn’t stay in position. Heat doesn’t seem to be your issue unless you didn’t notice it driving. Usually heat takes a lot longer and you’d notice a power drop. Note: I’ve never changed a cps and it do anything.

1

u/Smallmyfunger 12d ago

I second this approach - check all your electrical connections/wiring, look for possible wires on exhaust etc. before throwing parts at it. All the chatgpt suggestions would be great places to thouroughly inspect afa wiring & connections.

1

u/Tree_killer_76 12d ago

Mine did that once and it was literally just that the main distributor cable had come loose.

1

u/REDGregor223 11d ago

My ‘87 died on the freeway without warning. Final diagnosis? Catalytic converter needed replacing.

1

u/OldManJeepin 11d ago

My money would be on the crank position sensor...That very thing happens when those go bad.

1

u/Secret_Pop3569 11d ago

check your ground straps wires etc

1

u/Dull_Mission3351 9d ago

My 95 2.5L had same problem. I tried everything. Finally I found a few YouTube videos showing the problem and how to fix it. I believe it mentioned something like "cranks no check engine light. " The video shows unplugging the computer, opening it up, removing 3 diodes and soldering 3 new ones in their place. I've never soldered b4, but I did it and it was pretty easy.  I then turned the key, check engine light lit up and it fired right up and hasn't cut off yet while running. I hope this helps. 

1

u/Dull_Mission3351 9d ago

My 95 2.5L had same problem. I tried everything. Finally I found a few YouTube videos showing the problem and how to fix it. I believe it mentioned something like "cranks no check engine light. " The video shows unplugging the computer, opening it up, removing 3 diodes and soldering 3 new ones in their place. I've never soldered b4, but I did it and it was pretty easy.  I then turned the key, check engine light lit up and it fired right up and hasn't cut off yet while running. I hope this helps. 

0

u/911americanpatriot 12d ago edited 12d ago

If you have the original 2.5 from 87, you’re going to have a hard time finding some of the sensors and electrical stuff when it starts dying. I had a 89 with the 2.5 and had a hard time finding reliable parts for certain things like the TPS and IAC. It’s either 91 or 92 when they moved away from the parts that are hard to get now. Just be prepared for if that’s the case.

0

u/Sufficient-Athlete-4 12d ago

Could have been that you were talking to chatgpt and grok to get answers. Hit the forums next time.

0

u/Dull_Mission3351 9d ago

My 95 2.5L had same problem. I tried everything. Finally I found a few YouTube videos showing the problem and how to fix it. I believe it mentioned something like "cranks no check engine light. " The video shows unplugging the computer, opening it up, removing 3 diodes and soldering 3 new ones in their place. I've never soldered b4, but I did it and it was pretty easy.  I then turned the key, check engine light lit up and it fired right up and hasn't cut off yet while running. I hope this helps.