Jeep Strokers

After doing the break in on my new 4.6 engine and being started numerous times after that my 2000 XJ will not start. Changed CPS tested CPS, has spark has 50 psi to fuel rail, injectors firing but it will not start. Checked and cleaned grounds as well. Could this be an ECM problem and if so how can I test for that?

We took the coil rail off and put another set of plugs in the rail and cranked the engine. We got spark on all plugs arcing to the valve cover. Luckily I found a sympathetic parts counter guy that let me swap out the coil pack and cam sensor and return them after trying them out. So that takes care of spark. We verified 50psi at the fuel rail with gage, you can smell the fuel very noticably when you crank it over and the plugs are wet. Tried two different rails and a new set of 24#'s and the known good old set of 19# injectors. Makes no difference. So thats fuel. I have triple checked the CPS and the Cam sensor with a meter and have changed out each of these with new sensors. So that takes care of those usual suspects. Brought engine up to TDC on compression stroke and adjusted cam sensor according to instructions.
Tried old throttle body. It doesnt even act like its igniting. We pulled the jeep out of the garage and turned it around then put new fuel pump in with new regulator. Started it up a couple more times after doing cowel air intake. Then poof, it hasnt started since. Between the two of us we have worked on cars for many many years and at this point we are both stumped and dejected. Things were going so well with the new stroker engine.
Would a faulty ECM still throw spark and fuel signal?

Well, must have stumped everyone. Its a head scratcher for sure.

I am cornfused!

Cam timing ?

jsawduste wrote:Cam timing ?

As a possible idea John brought up, would be easy enough to give it a cranking compression test.
At least it would be another way to cross something off the list.

I could understand that if it hadnt ran so well just a week ago. Unless it skipped a tooth on the new timing chain set? Your right though, easy enough to check.

Any codes?

SilverXJ wrote:Any codes?

And a wild ass guess.......Could something have changed that is security system related ? Wouldn't think so but still tossing it out there.

No codes, and my XJ does not have the chipped key for theft protection.

Squirt some starter fluid down the intake and see if it starts.

Thats on the list of things to try. Kind of waited on that because you can smell the fuel after it cranks for 5 seconds. But time to leave no stone unturned.

If your getting fuel smell that fast I'd be looking for injector fly back voltage with a Noid tester.

Seems it's gagging on fuel.

Last summer I had one injector that stuck open. That cylinder would wet the plug and not fire. My chance of contain mated fuel affecting the injector ?

Stretching here but ???

I have a noid tester set due here today. I know its not an injector stuck because I swapped out the 24#'s back to my stock 19's and the result was the same. It could be getting a wacky signal from the PCM though.

Okay, luckily a friend of mine has a 99 XJ 4.0 automatic federal emmisions as his daily driver. He allowed me to swap my "suspect" PCM into his car. Unlike my XJ his started but ran like it was firing on 3 cylinders...nasty. Swapped his PCM back in and purred like a kitten. Im not sure this is 100% valid or even 50% but I'm thinking my PCM may be jacked up. Opinions?