Hello Everyone,

1995 XJ 4.0 Auto:
I am new to the Jeep world, i am struggling with this issue that was present when i bought the jeep 2 weeks ago. I have spark and fuel pressure where it should be, Checked and replaced plugs, Made a noid light for the injector pulse test, Injector #2 has P+ voltage of battery volts but is not receiving the neg- signal from PCM, Injector #4 have battery positive voltage and a weak light when tested, thinking it would be a ground issue?? I cleaned all plugs in engine bay as stated in other posts also made a ground from battery to frame, cleaned PCM wires and checked resistance on pins that send the signal from PCM to injector, no resistance present, Am i looking at a possible PCM issue internally?? Any input at this point would be greatly appreciated!! Also where are all the grounds around the PCM??
Thanks
Chris

 

See if a manual here helps you. http://cruiser54.com/?page_id=365

 

Definitely got me on the right track thank you very much. Last question, for now. When it says after T/O to injector what is the TO they are referring to??

 

I don't know.

 

Ok, So i cleaned up and rewired grounds at Dipstick tube and started tracing the 1 wire @ dipstick tube that has high resistance, that runs inside through the firewall and goes to a plug then changes from Black/Orange to Black/Green and into 2 wires. Lost the travel path after i got to the cluster of wires under the dash, any idea what that could go to, i am thinking the overhead console, but all i have up there is a light. Back to the injector issue, i back probed the #2 and #4 injector at plug and hooked Red lead to + and Black lead to the - from the PCM, i was able to see a constant voltage of around 12v, is this normal or should it come and go, or does it happen to quick for the meter to pick up on the change? I was originally thinking i had 2 bad injectors so i pulled OEM injectors and put them in, problem stayed with the same cylinder, Is it possible that the connection @ female side of plug is messed up, because it wont light a noid light on #2. Is it possible that the Crank or "Cam" sensor is not working correctly and skipping at the #2 and #4 position?? Sorry for being all over the place, just looking for assistance. Would like to actually be able to enjoy my new toy.

Also after installing new ground under dash i now have the turn signal indicator lights on all the time when the headlights are pulled? Could that be from the dielectric grease that i applied to the plug under the air box.

thanks
Chris

 

I'm not sure if your injectors are fired by adding power or adding ground. If by adding ground, your test with the meter sounds correct.

What all did you do with dielectric grease?

 

Well I figured out that when I applied dielectric grease to the headlight connector it shorted and caused the lights to stay on in the instrument panel. Also went to a local you pull it yard and found the last Xj PCM and swapped it out, #2 is now firing. #4 is firing but not getting fuel/spark. Have to figure out what's going on, pulled connector off #4 no change in motor. Too damn cold to be out for to long where we are at. Will advise when I figure the rest out.