No fire on a '90 Cherokee

I am considering purchasing a '90 Cherokee w/4.0 & auto. The problem is the thing has no fire. You can wind on it all day, but it won't fire up. The owner said that it was running great until he replaced the battery cables. Took it to a local shop to have the cables replaced and ended up towing it home because he could not get it to start. So, thinking that it must be something wrong with the ignition, he replaced the OEM distributor with an HEI unit...still no fire. I'm thinking it has got to be something electrical wrong with it and if I can get it running without throwing parts at it, than it would be one hell of a deal. I've search this forum but am unable to come up with anything similar to my dilemma. I'll admit I don't know too much about Jeeps. I've been driving and working on a '63 Scout for the past couple of years and I need something a little more modern and reliable. Any suggestions?

Thanks,
Justin

It could be a faulty CPS (crankshaft position sensor). That reads the flywheel revolutions and controls both spark and injection. However, it is unrelated to battery cables, so if the CPS is the cause, the fact it wouldn't fire up after replacing the battery cables would be very coincidental.

The CPS sometimes gives warning signs, other times it just fails. The one in my '88 4.0L Cherokee was perfect for more than ten years and maybe 150,000 or 175,000 miles (don't recall). Drove it home one evening and parked it ... the next day it wouldn't fire up.

After searching the forum the CPS sensor was one thing that I had in mind. Maybe it was by coincidence that it just happened not to start after replacing the battery cables. Know of anything else related to the battery that could be a possible cause?

Thanks,
Justin

A probllematic electrical connection can become even more so when the battery is disconnected. Try unplugging and re-plugging the CPS. The plug's located at the driver's side rear of the engine; should be laying on top of the intake manifold. This will sometimes cause them to work again (for a time).

Also listen for the fuel pump. It will 'click' for a few seconds when the key is turned on.

These Renix ignition systems are pretty easy to check out, if you're handy with a multimeter......

I will be going back this weekend to take another look at the vehicle so while I'm there I will try plugging and unplugging the CPS. Keep the suggestions coming.

Thanks,
Justin

Try the ICU (Ignition control module) if you know anyone with a renix ECU that you could try. Its located right below the coil. Its expensive $140. I had one go, and it won't fire.