Looking for an ECU for a 1992 XJ 4.0 6cyl manual, california emissions


Can you send old one out for refurbishing ? Very common to do this.
Would help to know What is wrong with one you have?
 
that might be possible. i have been looking around and have seen services for that. and i'm not for sure, there is a wire running directly from the alternator to the ecu and while i was under the car i accidentally sparked two connections on the alternator. i believe this could have shorted out the computer. besides this spark there was nothing else that happened and nothing changed.


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I would SCAN for codes - take a drive and lets see what we observe..
That wire - not in a bundle or harness ? hum suspicious Lets see answer to above question.

One of the gang here claims to have a goo d source for PCMs hopefully we wont need one.
 

i would love to do that, unfortunately it does not start because the fuel pump is not getting power and there is no spark. traced the fuel pump wire back to the ecu and gave it power using a tool i have, fuel pump turned on... there is a plug that is right next to the ecu that i believe would be for checking codes, but unfortunately i do not have anything that will fit that plug


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This is a 1992 - Cherokee XJ ?
the FP gets 12v from relay NOT PCM?
The FP is not constant power unless engine running...
The ignition gets power from relay...

We need to get you some wiring diagrams something is making mental picture cloudy.
 
attached is wiring dia - let me know what you find is this what you see
 

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wiring color is all different. as for the fuel pump relay wires they seem to be in the same location. as for the rest of it. it seems different.


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OK I was not sure of what model year you have and your description and my memory were not on same page.

I sometimes enjoy wiring issues a challenge to me....

OK I will look at my wiring manual see if something else.


KOEO and testing within @2 seconds is there 12v to - coil & injectors
 

is there 12v at the wires ? KOEO within 2seconds of key on
 
at the wires for FP no there is not 12v. the most i've gotten is a little over 2v. and no unfortunately those colors dont match up, i know that on the first diagram you sent wire 9 on the wiring harness is light blue and either wire 20 or 3 is gray. can't remember which one because i don't have the jeep with me right now


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I am guessing #3 and #9 are the pin outs at the ECM ....chec fuss in dia #2 and #35 fuse
 
replaced my old ecu with a rebuilt one, didn't fix the problem. got really mad and started searching and tearing car apart. found a little relay box that was hidden and upon opening it i found a fuse inside that was blown. replaced the fuse and the fuel pump will now turn on, i think i may have the wrong order for spark plugs now though, GREAT! well i will figure that out soon. but now when i try to turn it over it sounds like it is trying, it's sputtering pretty hard. i tried starter fluid and it did nothing. i tried fixing the spark plug order and nothing again... i am quite confused on what to do here


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timing info attached -

no start is BASICS -
is there spark a several plugs?
Fuel pressure use gauge .
Are injectors pulsing use a noid light.
KOEO I there 12v at coil and injectors?
 

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