JimmyMcDuff

1992 Jeep Cherokee Laredo 4.0L I6.

Just a few days ago, my Jeep started to idle high (1200+ rpms) and was shifting funny. Then it stalled when I pressed the gas pedal. This happens after the rpms during idle go up. When it stalls, it will not turn back on until it is cool again. If I wait till it's cooled down, the engine will flood and it will rarely turn on unless I remove the fuel pump relay for a few seconds. Then the issue repeats.

Replaced the following:
- CPS
- MAP sensor
- Ignition Coil
- Spark plugs and wires
- Fuel filter
- O2 sensor

Verified the following are working:
- Fuel pump
- Fuel pump relay
- TPS
- Battery and charging system

Check engine light came on but by the time I could run a self diagnostic test, the light was gone. I got no trouble code.

I am not sure what to do next at this point. Any help would be appreciated very much. I apologize if I am missing information.

RTorrez1

Where did you get you cps from? You need to get an OEM one if not already. After market ones are garbage and can be bad right out of the box. Also how did you verify that the fuel pump is working correctly. You need to test the pressure with a mechanical pressure gauge. You should have 39psi on the fuel rail. Next time it doesn't start you need to recheck everything to see what you're missing such as fuel or spark or both.

JimmyMcDuff

Autozone or Advance for CPS. I cannot remember.

Ok, amatuer question but where is a good place to get OEM Cherokee parts?

Ok, I'll check those and report back later today.

RTorrez1

They are garbage.

Dealer. I think that Rock Auto carries them to but not 100% sure.

JimmyMcDuff

Ok, sorry for the long wait. I replaced CPS with OEM one and checked the fuel pressure at the rail using the proper gauge. I am getting 32 psi at idle and 41-ish with it disconnected from the regulator.

One thing I noticed is that the RPMs have stopped jumping up to 1200. Idles around 900-1000 now even after being warmed up and driven around my yard. I cannot take it for a drive on the road yet. Road is too busy and I cannot break down on it.

Pumping the gas pedal and cranking the engine works sometimes. Other times, I have to pump the gas pedal and crank the engine with the fuel pump relay disconnected and then once it starts, immediately put the fuel pump relay back in.

Also, check engine light finally came on. Not sure if it is related or not but I got a code of 22: Coolant sensor signal out of range.

JimmyMcDuff

I THINK I resolved my issue.

I bypassed the coolant temp sensor with a spare electrical copper wire and it cranked up within 2 seconds (while warm). I pulled out the electrical copper wire and it pulled out a lot corrosive dust with it. So I cleaned the coolant temp sensor connector and reconnected it back. Cranked up fine like nothing was wrong and then drove pretty well. Going to test drive it much further tomorrow to see if the issue is completely fixed.