Engine problem 2.5 5 speed with 4X4

[wranglercory]

Ok here we go I am likely going to purchase a 87 MJ with a 2.5 in it 5 speed tranny and 4 wheel drive. The guy said that it starts up fine and idles fine but he said that when it gets to opp. temp it bogs down or dies and he said that it will start back up, I would assume that from that point it continues the cycle. I am trying to possibly get a few ideas of what it could be . I have decided it could be the computer since I have been told by a comanche club member that the computer starts working when it gets to opperating temp. What do you guys think. I own a 87 the same except its 2 WD and I'm thinking I could try swapping parts to the other one to locate the problem. Ill be getting it for $300 he has already went down from 500 so well have to wait to see it. From what he has told me about what he has already done to it , that it will be well worth it. Here is what he wrote .

 

i have a 1987 jeep comanchee for sale. It has the 2.5L 4 cyl engine, the BA-5 5 spd transmition, and the np231 transfercase. I have had the clutch replaced less than 3000 miles ago. The tires are still in decient shape and all match. the body is rough; the floor has holes in it that have been partialy repaired, there are rust spots all over, and it needs a new front drivers side fender and front and rear bumpers, the bed is still in great shape. No rust holes in the floor and the rearend is still intact. It has a large spidered crack on the front window but all the other glass is free of scratches and dings, the paint is faded maroon... Now the reason why i am selling my old work truck... It has an engine issue that i can't seem to debug myself and i don't have the funds to take it to a shop. It will idle all day long with no issue but as soon as it gets to opperating temp it bogs down and looses power as soon as the throttle is opened. That is the only issue ive ever had with this truck asside from the rust holes.

[Geonovast]

1. It's not a BA 10/5. Something you could point out to him. It'll be an AX-5.

 

2. The ECU is probably fine. It's much more likely that it's a bad sensor that the ECU starts listening to when it gets up to temp.

[dasbulliwagen]

:agree:

 

One up to temp, the computer starts reading the O2 sensor instead of relying on programmed values. I would start there, also coolant temp sensor for computer. I'm not sure that there are any other things that would cause temp related problems. Good luck, let us know what you figure out.

[wranglercory]

Is there a way that I havent figured out how to test for a bad sensor or is it just test them one at a time? Like a diagnostic plug

[Eagle]

Is there a way that I havent figured out how to test for a bad sensor or is it just test them one at a time? Like a diagnostic plug

Too old for on-board diagnostics. You have to test each sensor individually.

[Backroads]

I'd snag it up, then go to the JY and get a handful of used sensors and start swappin away with it!

[mjeff87]

O2 sensor

 

unplug it and run it, see if the problem goes away

 

Jeff

[wranglercory]

Thanks Ill start with the O2 sensor and go from there. If anyone has any other ideas I would appriciate them also. I will be going to look at it tonight after work.

[wranglercory]

So I bought the 87. I disconnected the O2 sensor and drove home with the heater on high about 10 miles and the truck drove great. I decided to drive it this morning and about half way to work it wouldnt run any higher than idle. I made it but I'm not sure what to do next. I will reconnect the O2 sensor and try to disconnect the temp sensor. to see if that makes a difference. Does anyone have any other ideas. The truck runs great at first and on the way home I thought I had hit a home run. :no: turns out Ill be doing a little searching to determin the problem, With the help of many of you better educated Manche owners. :clapping: . lets see what kinds of things we can come up with to try on the trip home.