No spark and checked everything

90XJ 4.0 Auto 4x4

I have changed the CPS the coil dist cap and rotor and checked all my relay swiches and I still do not have any spark when I turn the key . However, the jeep will fire ,but I dont have any spark going to the dist cap to the coil. Any suggestion or help would be great.

Please explain a bit more clearly. I don't understand how it can fire if it has no spark.

sorry about that . the engine will turn over with no problem at all.but no spark out of the coil wire and it will not start. do you think a neutral saftey switch would have anything to do with it?

If the neutral safety switch were the problem, it would not turn over. My first guess would be CPS, but you already changed that. Possibly the ignition module -- located beneath the coil?

I had a similar problem once it was due to a bad connection in the main harness

plug @ the fire wall ?

Eagle said:

Possibly the ignition module -- located beneath the coil?

Click to expand...

I had this exact problem once. The starter would turn, and I was getting a very weak spark. It was a burnt negative connection into the ignition module. I had to replace it.

Eagle said:

If the neutral safety switch were the problem, it would not turn over. My first guess would be CPS, but you already changed that. Possibly the ignition module -- located beneath the coil?

Click to expand...

It still may be CPS: check the harness that goes to the CPS plug as that sometimes melts shorts out.

"I had a similar problem once it was due to a bad connection in the main harness

plug @ the fire wall ?"
__________________

I agree with MTBKR.....and I'd check the harness. I've had this problem w/a Cherokee in the past.....but mine had some loose wiring....right around the injector/area. I found that I could move these wires around...and have somebody else cranking it...till I found the culprit. I had the exact same circumstances that you're referring to.
Aron

thank you guys for all the help. I changed out the ignition module with a used one. and I did recheck the connection on the cps. it was good. But I am not sure were the main harness connection is. could you tell me were it is at so i can check that.

Well guys I got it fixed. Bad thing was i had to take it in .My mechanic told me my coil wire was bad and my roter was broke but the crazy thing I checked all that stuff before I took it in. O well at least the SOB runs.

I have a 1990 XJ 4x4 4.0 Automatic.

Had to by-pass the ignition switch (after it quit turning the engine over) last year. Up till a few weeks ago it was running ok. It was getting harder and harder to fire up, checked the spark off the coil wire and the last time I saw spark it was orange not blue like the manual says it should be...

One day it just decided to not spark anymore. I can't believe the amount of people having problems with this! When I turn the ignition switch, power comes on at the gauges and everywhere else

There has to be a remedy. I have replaced the coil, ICM, plug wires, distributor cap, rotor, battery, checked fuses / fusible links, jiggled wires, etc, etc.

RDX

Well....

This afternoon I went out looking for the CPS to unplug/replug it seeing as it has worked for some people on the site. Supposed to be on the bellhousing around the 10 o'clock position(?). Didn't see that but noticed a vacum hose unhooked from something that was on the firewall directly about the vavle cover. The end of the hose was rotted quite a bit so I cut it off and replaced it. Decided to try it anyways as I had nothing to lose...

After 10-15 seconds of cranking I heard this click noise from inside the dash (Could of been the radio?) and the damn thing fired right up!!!!!!!!

Have started it and turned it back off about 20 times this evening and each time it takes no longer than 3-5 seconds to get it started every time...

I was just about ready to sell it REALLY cheap or call the junkyard after seeing all the post on this site relating to XJ electrical starting problems. I don't need something that is going to leave me stranded in the middle of nowhere towing Waverunners.

I can picture returning to the "side of the road" scene and finding my Waverunners gone and the non-starting XJ sitting there smirking...

Any clue what this vacum hose /piece is????

Also. what are the stock gear ratio's in a 1990 4x4 XJ? My rear end sounds worse than a gravel truck! Replaced the outer axle bearings but the sound is in the differential area. SEVERE!

Is there any other year XJ that will bolt in with no mods? There is a local Salvage Yard that has a few Grand Cherokee's with disc brakes on the rear...

Thanks!

RDX

rdx4me said:

Any clue what this vacum hose /piece is????

Click to expand...

From your description, MAP sensor. People just gotta suck-it-up and learn about the 4.0 EFI or find yourself standing on the side of the road with your dick in your hand wondering what to do. It's not hard or complicated but it takes effort to understand and electronics skill will always go a long way.

The rearends are a little weak on most of late 80 - early 90 XJ's. The pinion bearing shelled on mine about 200k miles.