Boatwrench
NAXJA Forum User
- Location
- Petaluma, CA
1st let me say thanks to all who helped by offering good advice.
Final. (I hope). The XJ is running, one electrical problem masking a second problem. Here’s a recap of the misadventures.
1987 4.0L/AW4/231 215K on the clock, bought at an impound auction. The vehicle would not pass smog due to the cracked exhaust manifold. Purchasing a manifold from DirectAuto.com for $143 shipped was an adventure by itself. Took 30 days to get it to me.
I installed the manifold, gasket and seal, replaced the fuel rail O rings, left motor mount, trans mount, spark plugs and the CPS. The manifold had one pipe broken completely around. The CPS wires were charred, so I figured it was a good idea to replace. The old plugs were soot fouled, not wet and mounts lead to the breakage of manifolds.
Went to start and it cranks but won’t start. Here’s what I did over the course of the last couple of weeks.
Previous post are here:
http://www.naxja.org/forum/showthread.php?t=942835
And here:
http://www.naxja.org/forum/showthread.php?t=943067
Decided all indications were an ECU especially since the ECU would not work in my 88XJ. Picked one up from 5-90, installed no joy. We had decided it was something easy and easily overlooked. At the meet-n-greet last week Bryan C told me to pull apart all the connectors and re connect, Opie told me to move the relays around. Thinking about this I double checked each connector I had removed to make sure it was properly seated, no pins were bent and none had backed or been pushed out. Here are the results.
Found one pin backed out of the harness side of the CPS. No Joy.:explosion
Determined that the cut violet and white wires were definitely from the Chrysler recall in the TSB. No Joy.:explosion
Tried an O2 sensor. No Joy:explosion
Tried the starter relay, No Joy:explosion
I noticed that an 18g ORG/BLK tracer was cut by the relay packs. One was dangling and the other butt spliced into a black wire that led to the negative battery terminal. Looked at the FSM and determined this is the fuel pump relay circuit. Checked for pressure at the fuel rail (again) and it was DRY!!!
The fuel pump relay coil was grounded directly to the battery, not through the ECU as designed. Using a DVOM determined no continuity between the relay terminal block and ground, the butt connector was loose causing an open. Removed the butt connector and with jumper wire grounded coil and checked crank, crank, crank, crank about to give up and VVVVVRRRRRROOOOOOOMMMM it starts!. Securely connected the two 16g ORG/BLK wires together into the original configuration tested it again, crank, crank starts and runs. Progress. Removed the ECU I got from 5-90 and reinstalled the original ECU. Cranks but won’t start, so I reinstalled the ECU from 5-90 and now have a running 1987 XJ.
I figure the mod or trail repair by one of the previous owners was due to the failure of the ECU to provide a ground to energize the coil in the fuel pump relay. I must have disrupted the butt connector when I was tweaking with the battery cables and starter relay. One problem was masking another. Now tomorrow to the smog test station.
Thanks for everyone’s assistance.:angel:
Now to just figure what the twisted tan wire at the ECU terminal C10 does and why was it cut and then just twisted back together...Oh the joys of buying auction junk.
Final. (I hope). The XJ is running, one electrical problem masking a second problem. Here’s a recap of the misadventures.
1987 4.0L/AW4/231 215K on the clock, bought at an impound auction. The vehicle would not pass smog due to the cracked exhaust manifold. Purchasing a manifold from DirectAuto.com for $143 shipped was an adventure by itself. Took 30 days to get it to me.
I installed the manifold, gasket and seal, replaced the fuel rail O rings, left motor mount, trans mount, spark plugs and the CPS. The manifold had one pipe broken completely around. The CPS wires were charred, so I figured it was a good idea to replace. The old plugs were soot fouled, not wet and mounts lead to the breakage of manifolds.
Went to start and it cranks but won’t start. Here’s what I did over the course of the last couple of weeks.
Previous post are here:
http://www.naxja.org/forum/showthread.php?t=942835
And here:
http://www.naxja.org/forum/showthread.php?t=943067
Decided all indications were an ECU especially since the ECU would not work in my 88XJ. Picked one up from 5-90, installed no joy. We had decided it was something easy and easily overlooked. At the meet-n-greet last week Bryan C told me to pull apart all the connectors and re connect, Opie told me to move the relays around. Thinking about this I double checked each connector I had removed to make sure it was properly seated, no pins were bent and none had backed or been pushed out. Here are the results.
Found one pin backed out of the harness side of the CPS. No Joy.:explosion
Determined that the cut violet and white wires were definitely from the Chrysler recall in the TSB. No Joy.:explosion
Tried an O2 sensor. No Joy:explosion
Tried the starter relay, No Joy:explosion
I noticed that an 18g ORG/BLK tracer was cut by the relay packs. One was dangling and the other butt spliced into a black wire that led to the negative battery terminal. Looked at the FSM and determined this is the fuel pump relay circuit. Checked for pressure at the fuel rail (again) and it was DRY!!!
The fuel pump relay coil was grounded directly to the battery, not through the ECU as designed. Using a DVOM determined no continuity between the relay terminal block and ground, the butt connector was loose causing an open. Removed the butt connector and with jumper wire grounded coil and checked crank, crank, crank, crank about to give up and VVVVVRRRRRROOOOOOOMMMM it starts!. Securely connected the two 16g ORG/BLK wires together into the original configuration tested it again, crank, crank starts and runs. Progress. Removed the ECU I got from 5-90 and reinstalled the original ECU. Cranks but won’t start, so I reinstalled the ECU from 5-90 and now have a running 1987 XJ.
I figure the mod or trail repair by one of the previous owners was due to the failure of the ECU to provide a ground to energize the coil in the fuel pump relay. I must have disrupted the butt connector when I was tweaking with the battery cables and starter relay. One problem was masking another. Now tomorrow to the smog test station.
Thanks for everyone’s assistance.:angel:
Now to just figure what the twisted tan wire at the ECU terminal C10 does and why was it cut and then just twisted back together...Oh the joys of buying auction junk.
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