2000 xj wont start after rebuild STUMPED

alright need some help from some people smarter then me. i just did a full rebuild on a customers 4.0 and got it installed sunday, the jeep cranks and will hit like it wants to start withing the first 2 or 3 rotations then it just cranks and cranks and acts like its out of time. i pulled the timing cover back off just to be 100% sure it was in time correctly as it was. i checked all the grounds and they were all good, i swapped the coil rail out with no luck, changed the cam sensor, have not changed the crank sensor as it wont typically hit at all when they fail.

im getting fuel, and clearly getting fire as it does hit and it honestly smells like its loading up with to much fuel. is there somthing here i am just over looking any help or suggestions would be more then appreciated

What is fuel pressure?

Get an actual fuel pressure reading. You might have such low pressure that it can't atomize the fuel properly, or some other such issue.

Could it be that something has been painted so well it is not grounding properly? (I did that to myself by powdercoating an alternator case--truck wouldn't charge anymore.)

Have you put a noid light onto an injector plug? Just checking for basics there.

I don't know enough about the coil rail system to offer any suggestions there.

It also might be worth considering why the engine failed in the first place. Not knowing the history I can't offer any help there, but there might be a useful clue down that road.

Anak said:

What is fuel pressure?

Get an actual fuel pressure reading. You might have such low pressure that it can't atomize the fuel properly, or some other such issue.

Could it be that something has been painted so well it is not grounding properly? (I did that to myself by powdercoating an alternator case--truck wouldn't charge anymore.)

Have you put a noid light onto an injector plug? Just checking for basics there.

I don't know enough about the coil rail system to offer any suggestions there.

It also might be worth considering why the engine failed in the first place. Not knowing the history I can't offer any help there, but there might be a useful clue down that road.

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fuel pressure is right at 45psi, i didnt noid light it yet as i let a friend borrow mine and havent got them back yet. i did think about the grounds when i painted the block and cleaned all ground locations after painting.

i just changed the cps and it starts up and runs now but ive got to finish putting it back togeather before i let it run any period of time.

i appreciate the reply and will update in a couple hours if the cps was in fact the issue, ive just never had one act the way this was from the crank but you can never expect anything when your working on a jeep :roflmao:

well it was indeed the crank sensor, again thanks for the help!