here is what I have, 96 Cherokee classic no spark no fuel the guy already put new pick up coil in and new cps . my brother in law and I looked at it and he thought it needed ecm ( the relay box under hood and the cruise module beside the relay box would go crazy when key turned on) the owner sent for reman ecm when I installed it still no start will crank but no fuel or spark. Also when key is turned on cel does not light and I cannot communicate whith code reader, relay box no longer goes crazy but still no start.

I have done all the ground refreshing and brother in law done a few electrical test everything seems to be working except no communication and no cel when key turned on..any ideas don't have clue where to go from here

little more info, before the no start he would be driving and jeep just stall take awhile then it would start back up and run fine, when it started stalling out the cruise control light came on and you cant get it to go off power button has no effect stays on all the time. we did get it to run one time after ecm change and he started it a day later I went to get it to change altenator and it wouldn't start and haven't got it to start since.

 

Have you tried swapping the ASD relay?

 

yes swapped ASD, cleaned all connections

 

bump

 

Did you post this on JF as well? Is this a crank but no start or a no crank no start? Since this will be different in approached somewhat...

 

What brand was the new CPS?

 

That was the question I asked on JF as well...

 

It was autozone I believe but we did get it running a couple of times since changed the ecm.

It is a crank but no start issue.

when I turn key on I don't get a check engine light and code reader will not communicate with ecm. once in awhile the cel will come on shortly and code reader will communicate then and it will start but dies shortly and looses communication.

 

It sounds like you have an "intermittent" bus issue. One of the main symptoms of that is you cannot communicate with the computer to read codes. The bus is the very large circuit that carries all of the critical signals to allow the engine to fire. It covers a lot of ground, unfortunately.

This is going to take some serious troubleshooting with a meter and the wiring diagrams. These things can sometimes be difficult to isolate. Good luck and keep us updated!

 

ok looks like your right about the ccd bus have no voltage in bus pins at dlc.

on the 96 does the ecm make the bus voltage because im not quite convinced that the reman ecm he bought is good.

I guess what im asking is if I check the bus pins at the ecm and have no voltage would that narrow it down

I have unplugged cps still no voltage

unplugged pick up coil still no voltage

tps no voltage

and any other sensor I can find

need help finding a schematic for the ccd bus ive been searching but haven't come across one yet

Ok think I finally found the schematic for the ccd bus now just to find out what all modules this jeep has.

Thanx

 

You have a '96, all bets are off, lol. I didn't think the CCD bus started in the XJ until 1997. My '96 still had a mechanical odometer and no CCD. Do you have the digital odometer or mechanical?
I think you might have a wiring harness/plug/connector issue. I'd take a good look at the PCM connectors and give the wiring harnesses a good shake while cranking the engine.

 

Check all fuses in both fuse boxs for power in and out with key in run position. Also check for bad connection in cel bulb light socket .

 

ok have checked all fuses more than once everything good.

as for cel if I pull fuse for power to ecm cel comes on

how can I find out if 96 is suppose to have the power on ccd bus
it does have mechanical odometer but should it have power on dlc at ccd bus pins

 

have checked ecm pins 28 and 30 have 119.5 ohms

checked dlc pins 3 and 11 120 ohms

checked ohms from dlc to c3 connector pin 11 to c28 <.5ohms

pins c30 to dlc 11 <.5 ohms

cleaned c3 connecter again put back together started right up ran for about 30 seconds shut off and cant get to run now.

silly question cruise light on steering wheel on all the time cant get it to shut off. could it be shorting something out. That's when all this started

what fuse powers the cruise don't list it in the owners manual

 

IIRC the cruise is powered by a pin on the PCM, there isn't a separate fuse.
I don't recall if there's a connector to unplug the steering column cruise wiring, but if there is I'd sure unplug it and see if it starts.
What do the pins look like in the C3 connector? Anything loose, bent or discolored?