So my jeep recently started acting up. It will crank and sputter and cough (misfires or timing going off?) and sometimes it'll start and just run awful like not on all cylinders and then it'll stall. Eventually, it'll fire up and run perfectly fine. But now, it won't fire up at all.

I recently replaced the CPS and TPS and to try to fix this I've cleaned the throttle body, checked fuel pressure (40psi when primed), checked and cleaned ECU plugs, and cleaned battery cables and terminals.

Nothing has yielded any results so far and it's really confusing me so any help is appreciated.

Also, when I was looking around the engine bay I noticed a plug just hanging there near where the transmission wires go into the harness, I'm not sure if it goes somewhere or if it could be the cause of my problems so if anyone knows what it's for that'd be awesome. (It could just be spare, the jeep was originally 2wd but I converted it to 4x4 with a 98 trans)

 

have you tried getting someone to wiggle the wire harness that connect to the ECU while cranking? it is possible for the whole unit to be faulty. . when they go bad they will they will fire sometimes and others not at all. also it'll run as if its only on a couple of cylinders at times then go back to normal.
worth a shot!

 

Well I gave that a shot and nothin happened. It won't it sputter or cough anymore it just cranks and cranks.

 

Did you try squirting a little starting fluid in the TB to see if it kicks? Do you have spark. Pull a plug and check..don't get shocked..it sucks..

 

How do you test for spark with the distributor less ignition system?

 

Pull the coil rail. Get a plug..ground the plug threads and crank..kind of a two person job.

 

If you had a 2001 XJ I'd venture a guess that connector is for an Ignition Coil Capacitor (see pic), That device above it looks like the capacitor (not connected).


Maybe late production 2000 XJ's had the capacitor (?).

 

^

 

Well I tried spraying some starter fluid in the TB and it fired so now I'm thinking maybe injectors? Is that a possibility?

 

I can not express how much an OEM MOPAR Crank Sensor is important to use to rule out it is not the Crank Sensor.

Yes, many times an after market Crank Sensor will work, but many times it WON'T !!!!!!!

 

Not likely, at least not the injectors themselves. Use a test light/ohm meter, etc to check for power to the injectors. Check both the +/- sides of the plug. IIRC the pos is always hot when running, the trigger signal is the neg wire. This is a two man job, trigger signal will only be there when the engine is running or being cranked.

 

Well I tested the injectors, all are fine. I replaced the cps again, and I even replaced the coil packs/coil rail/ whatever you wanna call it. I'm really getting frustrated with it. Is there anything else to check? I've determined that it is not getting spark now

 

if you suspect that the problem is in the fuel sending unit because of jeep cranking and cranking but start. heres a simple test. hit gas tank with a hammer near the pump location. not to hard and if u have a rubber mallet even better. if it starts then no doubt pump is the problem. gears inside sending unit need to interlock to creste

 

OK this is weird... I didn't post this. Anybody else have this happen?

 

Hello? People?

Why is Turbo the only person to see the problem here?


He's only got 40 PSI fuel pressure. Spec calls for 49.