ZachRitchie
NAXJA Forum User
- Location
- Arizona
New owner of a 1992 Jeep Cherokee 4.0 Auto that I bought for my son as his first vehicle. I’m going to add unnecessary details just in case something stands out to one of you guys because I’m at a standstill. Sorry if this is long! 1 month after purchase my son blew the motor (230k miles) it blew from a bad! overheat condition, he knows now that 290 degrees is a smidge too warm. We towed him home in neutral (neutral safety switch problem??). I picked up a re-manned from AutoZone, all numbers match, head, block etc. Swapped everything over and threw it in. Replaced just about everything well I was in there as well, the entire cooling system, distributor and wires, plugs, intake, o2 sensor, and ALL “drive” sensors. This is where it starts to get fun! No spark! No power at the coil. Cranks and Cranks...Grounds have been checked and checked again. Timing has been checked and checked again and tried different ways as well. All fuses checked out. I’ve tried 4 different CPS, all ohm out a little differently and I’ve bought them from all different places except Jeep OEM. I then fell into the rabbit hole of the ASD relay. I’ve tried jumping ASD relay inputs 30 to 87. Replaced relay of course. Relay does click now (didn’t at first) and fuel pump primes for 1-2 seconds. (I have fuel and pressure) I’ve done everything that is online for the ASD relay “fix”, so much so that I don’t even remember what I’ve done, I’ve been at this no spark for almost a month. I’ve done my best to test the PCM and he are some results. (I can get numbers from ASD too if that would help you)
Pin #6:
Ignition off – 2.4v
Ignition on - 5.05V
cranking – 5.35V
Pin #7:
ignition off- 2.39v
ignition on – 7.85v
cranking – 8.75v
Pin #3 and #9:
Between 11.5-12V
Ground at Pin #11 and #12:
Good
At this point I’m thinking it’s either something VERY silly or PCM? I’m in too deep $$ to stop here. I’m also out of ideas. We don’t believe the jeep has the factory security system as I read online that could be a problem. Battery always fully charged. Coil looks new. At this point I’m just coming up with random ideas that are getting me nowhere! So here I am. First post here, Any help or ideas would be great. Thank you.
Pin #6:
Ignition off – 2.4v
Ignition on - 5.05V
cranking – 5.35V
Pin #7:
ignition off- 2.39v
ignition on – 7.85v
cranking – 8.75v
Pin #3 and #9:
Between 11.5-12V
Ground at Pin #11 and #12:
Good
At this point I’m thinking it’s either something VERY silly or PCM? I’m in too deep $$ to stop here. I’m also out of ideas. We don’t believe the jeep has the factory security system as I read online that could be a problem. Battery always fully charged. Coil looks new. At this point I’m just coming up with random ideas that are getting me nowhere! So here I am. First post here, Any help or ideas would be great. Thank you.