Comatose Jeep!

[DaddysGirl]

Hi!

Guaha I have just discovered this place!
I have a 90 jeep Cherokee and ooohhh the problems I am having!
Would any of you know where I can get a diagram of the engine and/or electrical system?

The beast wont even start now.. before it would just shut off at a stop light or do that weird jerking thing as if I was giving it gas suddenly, now she died or is at least comatose!
Daddy refuses to take her to the mechanics [ must be a pride thing] but he doesn’t know what the issue is either.

[capt. apathy]

a couple of things it could be, the first thing to come to mind would be the CPS(crankshaft possition sensor, it controls the spark timing).

one thing that seems to be fairly common is conection problems where various sensors plug into the wiring harness. it's a good cheap place to start. just unplug, clean out the best you can, and reconect the sensors for the CPS, coolent temp, tps, Idle-air stepper motor.

there are others here who have more experience with more serious problems, but more often than not I can fix my starting problems by replacing or cleaning the conection on a sensor.

[b1gfella]

If your still looking for information, I just bought a Real 1994 Jeep Shop manual from Faxon auto literature. It was 74 bucks but looking through it, well worth the money as it covers things in alot more details than chiltons or haynes. Give them a call, they may have a shop manual for the 1990 model year as well. Chiltons and Haynes are not bad manuals either. I have copies of all three that I have picked up over the years.

-----snip-----
You may call us at (800) 458-2734, or e-mail [email protected] if you have any questions.
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This was from a shipping confermation e-mail I got from them.


John

[spooleffect]

I would guess you either have a tps problem or an aic problem or both with the jumping prob.

As for the no-start, check for fuel and spark.

[GunnyJeep]

here is a link for the engine schematic for a 1990 XJ

http://209.238.200.129/gw/elec/cherokee/91076b23.pdf

and for the chassis

http://209.238.200.129/gw/elec/cherokee/91076b24.pdf

also do you have the 4.0 or 2.5 engine and is it an automatic or stick?

the other suggestions are all good points to check, but I have to ask have you checked the fuel flow/pressure to your injectors? even tho you may be getting fuel to the injectors you might be getting it at low pressure.

and if none of the other suggestions help one other thing to look at is the O2 sensor (my YJ started having a problem close to yours, turned out to be a bad 02)

good luck and keep us posted