Hey all,

Having issues with my '87 2.5L Cherokee. After driving for a while it tends to bog down and idle rough when stopped at a light. When I go to take off it hesitates for about 2 seconds and then kicks in, but only after putting my foot the floor. I've noticed that when I go up my driveway, and it hesitates, carbon will shoot out of the exhaust. At lights it feels like it wants to die but it won't, but it does take a lot to get it going.

Here's what I've replaced:

- Plugs/Wires/Cap/Rotor
- Fuel Filter
- Flushed Rad
- Cleaned TB
- I had to put on a cat to pass emissions

So what do you guys think? I'm thinking it could be O2, but I also know i need to clean my IAC, and TPS. Is there anything else I need to check?

Thoughts and opinions welcome! TIA

 

Coolant temp sensor. When it fails it defaults to a value that is read by the computor as -45degrees which will cause it to increase the injector pulse resulting in to much fuel,....hense the black smoke and rough idle.

 

my old 87 was doing that. it was smokin like a diesel and barely running when you let off the throttle. fine going down the highway, well at high rpms it ran fine.

 

Is this something i can clean? Or just replace it?

 

Just replace it, not much money about 25 bucks

 

hey you may want to go have your whole exaust checked out, i know mine had a clogged cat and made it run similar to that. (i have the 2.5 by the way) That turned out to be the only thing wrong with it. Just have your cat checked out, it may have a factory defect in it or had a clog before you put it on

 

I'll replace the sensor and have the exhaust system checked out. Thanks for the info guys.

 

Ok so I took it in to get the exhaust looked at and they said everything was fine on that end. I went and bought a Coolant Temp Sensor, but I don't know where it's located! I'm working out of one of those Haynes manuals, and it's saying it should be located on the thermostat housing.

Now even I know it should be somewhere around there, but if I'm looking at the right thing, the thermostat housing has 2 hoses coming from it, but I don't see where the sensor could be.

Any help, please?

 

Never mind, i found it.

Thanks again for the help fellas

 

Sounds like the problem I had with my 90 MJ 2.5. THe fuel line on the pump that goes to the metal tank piece had dry rotted. would pick up fuel fine when it was full, but drop off once lower.


I would say it might be fuel related. either bad hose/pump.

 

I'm starting to think that this might be the issue. I bought the sensor, installed it, and it didn't change anything. It's weird because this only happens when it's warm. For example, I took it out to get some gas, and all was good. On the way home I was doing fine, got to my street and it started to hesitate, and it felt like it wanted to die. I was going up my driveway and it finally stalled, and it wouldn't start again.

Next morning I woke up, went outside, and started it up just fine. Pulled it in to the garage, and it's been sitting there ever since.

This is getting frustrating.

 

Those symptoms are very similar to the ones I had. Mine would cut out at speed too, and I would have to pop it back in gear to start. Wish I had took pics of it, but the hose was definately dry rotted.