'04 jeep 4.0 Compression locked? Ideas?

[ech0sh4y]

So I figured all the other forums I've posted on, no one can figure it out. Why not the try the engine forum!! Here is the low down:

I purchased a used 4.0, said to have 20,000 miles on it. I installed it and all was fine, went to start, fired up but seemed to have a horrible miss to it. Changed the spark plugs found the old ones were gaped at .20 and the back two were sooty, while the front four looked normal. So I figured score easy fix... no so much. I installed new plugs and tried to start. Cranks over once and it seems like it locks up. Thought it was a dead battery. Negative. So I pulled the plugs and tried to turn it over, turns over freely.

I've checked - Starter/battery/Hydro lock due to fuel injector... no one can figure it out. It seems like the valves are opening at the wrong time. I pulled valve cover and everything seems to be working normal. I can only think that the timeing chain had jumped or something? It ran before but had a bad miss.. not it won't turn over with plugs in! I have a broke 4.0 in the garage that i'm thinking of building a stroker to swap in place of this POS AHHh

Ideas? Testing? Anything!?

-Brian

[Bodo]

jumped timing chain?

[Exos]

Maybe your crank position sensor is damaged or faulty. I would look at that first.

[ech0sh4y]

Well I figured out that the starter wasn't getting enough juice. So I can get it to run. But it still seems to have a horrible miss. If you don't give it a little throttle it will kill it's self. -_- I am going to check fuel pressure somehow and see if maybe that is the issue.