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Jeep cranks won't start

4K views 6 replies 3 participants last post by  crazyrican 
#1 ·
Hey everyone. So the other day I was driving about a **** away from home and suddenly jeep died. Cranks but won't start now. My jeep is a jeep tj 1999 4.0l.

Earlier that day , I swapped out both o2 sensors and spark plugs and cables. I have them on the right firing order 153624.

Anyway, so after towing back home. And started to check my previous work. Come to find out the crank shaft sensor was pretty loose. Wobbling and when I touched it I could hear the fuel pump turn on. So I swapped that out. Try to start, no start. Turns over but won't start. So I check for spark. No spark. I switch out the coil. Now there is tons of spark. Still won't start....

I check for fuel. Checked fuel pressure and it reads at 40 with the switch on. Checked multiple times. So i have a functioning fuel pump.

I checked air pressure at spark plug. Cranked 3 times, gave me a reading of 140 psi.

Poured starter fluid in throttle body. Nothing. Still won't start.

Checked spark plugs again. They where pretty dirty from all attempts. Cleaned and reinserted. Nothing. They smell like fuel so I know gas it's getting there.

Can this be the timing belt?? The vehicle is a 160k. And I think it maybe jumped timing and won't get the pressure it needs to start.

I've checked every thread and forum and I have nothing. Waiting on a obd diagnostic tool o had ordered to help out.

Let me know if you ever had this problem or know or think what it can be.

Mike
 
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#2 ·
4.0 has a timing chain

Basics first rail pressure should be close to 49 psi

Are injectors clicking with cranking listen or noid lights

Do you have spark while cranking at plug end of spark plug wire

If all that ok and you are sure you have ample good gas in tank next pull all plugs and check and record all six compression values

Then if all that ok time for zebras like plug wires rotated to wrong spots on distributor cap or timing chain slipped
 
#4 ·
Injectors are clickin, got plenty of spark at the wire , full tank of gas to include I sprayed starter fluid in throttle and did not start also.

I do the compression test on 1 plug. Will have to do on all.

Thinking it could be the last one u mentioned a slipped chain. But hate to take all that apart and that not be it.

Thanks for reply
 
#6 ·
With loose chain can rotate crank more without dist bung rotating

First you put a wrench on crank after removing dist cap and insure rotor is turning with forward crank rotation then turn back and observe how far you turn wrench on crank before dist starts to turn the looser the chain the more the slack the further you must rotate crank back before dist bung starts to turn
 
#7 ·
For anyone wondering what the problem was, it was multiple issues to begin with. First off , the jeep was running on wrong spark plug cables due to auto part mistake, after switching these, the jeep started but failed. Secondly after further diagnosis, it was determined that the ignition switch was bad. Replaced, jeep runs great. Tha KS for the replies.
 
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