Mechanics

JEEP GRAND CHEROKEE SENSOR PROBLEM

1994 Jeep Grand Cherokee • 327 miles

I have a 94 JGC (5.2L) that I have been driving for 8 years. Last Spring I replaced the PCM because the engine would not start (unless it sat with ignition ON for 1-2 minutes). After replacement of the PCM, MAP sensor and a good tune up the vehicle ran better than ever for six months. It started to stall and stumble when cold and would have a slight misfire after warming up. After a couple of stalls in traffic I stopped driving it. After sitting for a few weeks it would not start at all. I found that I had no fuel pressure so I replaced the fuel pump and filter. Then after getting fuel pressure back I had no spark at the coil. I replaced the Crank position sensor (old one was split open and swollen), cap, rotor, wires, coil, battery terminals and cleaned the electrical grounds. Now I get a weak spark out of the coil secondary, but not enough to fire off the engine. Cranks good and strong. Voltage at the coil primary is good. PCM signal to fire the coil is good too (used a test light on the coil plug during cranking and light turns on and flashes strong during cranking). I tried another new coil but same situation. All parts have been Mopar parts (no aftermarket). I hate to have to spend any more money on it if it isn't going to fix it. Any ideas where else I can look to get this working? Thanks.
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Guest
January 2, 2013.



Scan for codes first it may be the crank sensor connection or cam senosr /connection

Hmac300
Jan 2, 2013.
I am not getting any codes (only 12 and 55). I would expect that since I am getting a ground pulse on the coil primary and the injectors are firing that the CAM and CRANK sensors are working correctly.

Tiny
Lonallen
Jan 2, 2013.
You'll have to check for resistance which we have not figures on, but they can be bad and not show a code.

Hmac300
Jan 2, 2013.