1992 Jeep XJ 4.0, well-maintained, 175k miles


Just recently replaced all fluids, water pump, steering pump, idler pully and a tranny flush. I also replaced the struts and some other stuff unrelated to the engine.

Anyway, I started hearing a screeching noise coming from the engine bay and the initial diagnosis was the AC compressor. We pulled that and installed a bypass pulley and that was when the engine started giving trouble. As it turns out, it was the steering pump pulley grinding on the bracket so we fixed that and reinstalled the compressor, thinking maybe something we did there was causing the engine to not start.

Well, that didn't work either. I think the engine is having a hard time turning over because it is running rich. It smells like fuel right after you start it and it smokes a lot for a few minutes. Also when we pulled the plugs they were CAKED in black carbon and they were in good shape not too long ago.

I can get the Jeep started with some vigorous pumping of the throttle. I floor it until the engine starts to catch then I start pumping like mad until it can stay running on its own then I let it settle into its idle. If you gas it the engine will hesistate around 1500rpm, completely lose revs for a split second then rev up however high you want it. Just like if you were revving at a red light. vroom vrooooooooom. I drove it for about 20 miles up and down the freeway and it cleared up and drove great and smoothed out. Stopped to eat at a restaurant, got back out and bam the engine didn't wanna start without the rigamarole with the throttle.

So now it sits, a ***** to start and I have no idea why. I can't think of anything that could have caused this from only removing the AC compressor.

Thanks for any help, it is appreciated!

 

Oh, forgot to mention, no error codes or CELs or anything. There is fuel pressure at the rail, the injectors are spraying clean and the fuel pump seems fine.

 

sounds like it's running rich. fix that and it might fix the starting problems. things I would do. change O2, temp sensor, thermostate. check spark. check wires. make sure right spark plugs. make sure injectors are not leaking into the cylinder. and since the plugs we're fouled, check compression.