I have an 89 with the 4.0. Ran fine one day parked it, washed it, next day went to start it and nothing just cranked and cranked. This was back in September. So I got on these forums and read everything I could find so since then I've replaced: CPS, distributer, plugs, plug wires, coil, starter, battery, ECM, cleaned all the grounds, good compression and timing is correct. If I spray starting fluid still a no go. Has a good strong spark and fuel on the plugs. Unplug the crank sensor and it cranks even and normal. Plug it back in and cranks then bogs down cranks then bogs down. I've used 3 different crank sensors and no change. I'm out of things to try I've checked and rechecked everything I know. Any ideas would help.

 

You've changed so many things now, it's gonna be tough sorting the original problem from a new one that may have been introduced with all the changes.
For starters- is the distributor timed correctly? From your description it sounds like it may be off.

 

Did you wash your engine?

If it won't run on starting fluid, you most likely have a coil, CPS or other ignition issue. The starting fluid will run most any Cherokee even with terrible compression or spark issues. I would be thinking along what Radi is saying: timing way off, wires on wrong plugs etc. I wouldn't start looking at fuel issues either (pump, filter etc) until I could get it to run on ether spraying into throttle body.

How did you check for good spark?

 

No, I just washed the exterior. I the plugs are all routed correctly I've checked that several times. I checked the distributer. Set the motor at TDC pulled the cap and the rotor was pointing at 1 so it looks good there. I pulled the number 1 plug and cranked it with it up against the valve cover and it has a good strong looking spark.

 

http://cruiser54.com/?p=68

 

I've ran through the tips cleaned every connector on the jeep. Refreshed all the grounds (some were pretty bad) but it didn't change anything. I was looking on this forum and I found a thread from last year where the guy had the same problem. He posted a video where you could hear the weird cranking and it sounds identical to mine. But the thread never said what was wrong so I decided to start my own

 

Good idea. Let's get to work.

Is your CPS wire routed properly where it isn't getting burned by the exhaust? Have you verified the output of the NEW one?

You really need to do Tip 13.

 

Ok, I have not checked the new one. I will do that and yep it's obit touching the exhaust

 

Not*

 

So I just read tip 13. So pretty much what you are doing is giving it a more exact reading, correct?

 

Yes.

 

Ok I'll do that

 

So I have a new development. The injectors are not squirting now. Can the distributer fail but still have spark? I have a buddy who has a code reader but he won't be able to bring it over for a couple weeks. I'll put what I found out on the crank sensor

 

Crank sensor is registering .32 ohms

 

I'm new to the forum so I'm gonna to try to upload a picture of what I just found. Not sure what it controls but it's pretty corroded. Just curious if that could have something to do with it