This is killing me.

So, a couple days ago, my CPS decided it didn't want to work anymore. I replaced that, and still nothing. I went from a thought bad one, to a brand new mopar one, and that didn't work. I stuck the one off of my 2wd trans on there because it was a known good one, nothing.

I decided to replace my coil, it was the original one from 1988. Still nothing. I cleaned the brass contacts on my distributor cap and rotor, still nothing.

I have no spark at all. I have 12 V going to my coil. I have fuel pressure. I have fuel delivery.

I replaced my NSS on a hunch, my reverse lights stayed on all the time and it would start in any gear. That didn't do anything.

I tested the resistance on my ballast resistor on my inner fender, good. I jumped it anyways, and still no start.

I'm thinking the next thing to replace is the pickup coil in the distributor.

This thing is killing me. If anyone has any ideas what else it could be, please share.

Only other thing I can think of is the TPS.

Why do you say TPS?

On mine I was having the same issue finding the problem, it turned out to be that the 2 wires that go into the coil had the rubber sheaths melt off them and were arching every time I tried to start it. It a long shot, but worth taking a look. I'd just check all the wires relating to starting.

Don't forget to check all wiring and connector associated with the crank sensor. I've seen melted/broken wires/harness problems cause a no-start. I believe there is a technical service bulletin for 87-90 vehicles regarding this.

What you need to do is to confirm that the crank sensor signal is making it all the way from the sensor itself into the engine bay and into the computer. How handy are you with a meter?

I think the vehicle would start with a bad TPS. The camshaft position sensor (in the distributor) can be tested. I'd start testing components before replacing them; it's more efficient and a heck of a lot cheaper! Good Luck!

You said that you replaced the coil but underneath the coil on an 88' is the ECM engine control module. When this goes you will have a no start condition. The coil plugs into the ECM.

The TPS has absolutely nothing to do with whether an engine has spark. How about an ignition module, have you replaced that?

Chris

try that distributor pick up coil, they do go bad. supposedly it won't cause the jeep to die while it's running, but in my jeep it certainly did. myself, i've never seen a renix ignition module die. although obviously that doesn't mean they don't...

The pickup (sync signal generator) can easily be tested with an analog volt meter. Searching should bring up how to test it. If you don't have a copy of the Renix service guide that's floating around, find it, it really helps with the testing of components and diagnosing of problems.

Here's a long shot, 87's and 88's could have had a patch wiring harness installed to wire the CPS directly to the ECM. Part of the repair was to cut the old CPS connector off of the end of the fuel injection harness so you couldn't mistakingly plug the CPS back into it. Could this have happened to you while changing the CPS? If the patch was installed on your truck, the new CPS harness comes out the firewall about an inch under where the big bundle of wire comes through, and the new CPS connector should be wire tied to the harness near the MAP sensor.

Inspect crank sensor wiring harness all the way to the computer. If you have a damaged or burnt wire, your XJ won't start. DISCONNECT the crank sensor connector located in the engine bay near the firewall, I believe by the #6 injector; clean it with electrical cleaner and re-seat it. Use a meter to ensure crankshaft position signal is making it to the connector under the hood. Inspect all wiring around distributor very closely. Freshen all engine grounds, even if they look good. And yes, the ECM could also be suspect. Test the camshaft position sensor. It is time for some serious testing at this point. If you can't find it yourself, you'd probably be well served to take it to a reputable shop instead of throwing any more parts at it. Good Luck!

I've got power going into the coil, and out the coil wire to the distributor. But its all the same voltage. I cranked the engine over with the red lead to the volt meter in the end of the coil wire, and i had a little drop due to cranking. So something is making my coil not fire. my pickup coil is good, my ignition coil is good, CPS wires and sensor are good. ASD relay is good.

Did you ever check the ignition control module as already recommended? I checked my manual and it says that you need an approved ignition control module tester (Tester J-24642E or equivalent) to test the ignition control modules; maybe somebody else has an idea of how to check it out without this tool or just replacing it....

Check all the fuses. One them, I cannot rembers which feeds power for the ecm and cps. I am driving around on my laptop and due not have specific fuse. I blow this one everyonce in a while and it mimics cps, when you replace this fuse with key on you will hear the asd click. Hal


:scottm:

88manche, Did you ever find the cause of your problem?