88 xj ECU wiring harness pin location

Just as the title says. A buddy of mine has an 88 xj and when we were doing some diagnostics we found the computer to be bad. Now this could or could not be the case as when unbolting the ECU there were two wires that had been removed from the harness. Why would anyone want to remove them? No clue. The wires are vio/white | blk/wht. I believe this is for the engine speed sensor. I do not, however, know where in the harness these two wires are supposed to sit. The schematic that I have just shows what the wires go to, not the actual location in the harness the wires are supposed to slide into.

BTW, the wires still have the spades on the end of them. It just seems fishy to me as there have been some major problems getting this engine to work right and then come to find out there are 2 wires that aren't plugged into the ECU harness.

Much help needed as this is his DD and we've been working on this thing to get it road ready for almost a year now. He's replaced every single sensor on the motor, new injectors, fuel rail, fuel filter, head gasket, etc. The list goes on and on. Probably bought the motor about 3x's by now.

The speed sensor hooks to the D1 + and the C1 -, my schematic shows the C1 as a violet wire and the D1 as white with a tracer (could be a black tracer). But the speed sensor isn´t the only violet wire. If your C-1 is occupied, I can look up the other possiblilities. Would probably be a good idea to run a continuity check from the speed sensor to the wire end and a check for short to ground, before hooking it up.

'87 and '88's had a TSB to hard wire the crank position sensor to the ECU, bypassing the underhood wiring harness and the C101 connector. If the TSB was done, you can follow the CPS wire from the sensor and instead of plugging into the main engine harness, it will plug into a smaller harness that goes right to the firewall, about an inch below where the main harness goes through. When someone removed the original wires from the ECU connector, the ends should have been snipped off and taped back. Maybe someone missed this step and those are the two wires you see!! Otherwise, :dunno:

the early xjs had problems with cps. this just eliminated the majority of the wiring harness and directly hooked it into the pcm. dont worry this is good

Thanks guys. I'm going to have a look at it right now. I hope that this was part of the TSB, although we did just put a new computer in and the idle seems to be wavering up and down. Also still getting quite a bit of black smoke coming from the tailpipe indicating a rich running condition. Just a bit of luck and I think we'll have it fixed.

anyway you can email that schematic to me? I really wanna have visual representation of it as I'm not electric genious. PM me for my email address.

you didnt loosen the map sensor vacuum line did you? also clean the throttle body and iac motor cavity

Pretty sure that the MAP sensor has been replaced as well as cleaning out the IAC cavity, but I'll have the cavity checked out.

No word on the pic of that schematic? The wires that come from the CPS don't go to the little harness on the firewall, they go into the main wiring harness, so please help me out with a pic of the harness. Hell, anyone here with an 88 XJ that can get me a pic of thier wiring harness plugs that go into the computer will be much appreciated!