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Discussion Starter #1
I have a 97 jeep wrangler 2.5l 4 cylinder that won't start. I was driving down the road and running fine then it just quit. And started backfiring. I've changed throttle position sensor, crank position sensor, cam position sensor, but still nothing.
 

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Sounds like you've may have lost your fuel pump? Do you have fuel pressure at the rail? The back firing before it died could be it running really lean while running out of fuel. Since you have replaced the obvious... I'd look at fuel.
 

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Discussion Starter #9
Sounds like you've may have lost your fuel pump? Do you have fuel pressure at the rail? The back firing before it died could be it running really lean while running out of fuel. Since you have replaced the obvious... I'd look at fuel.
I can hear the fuel pump kick on. And it won't even hit with starting fluid. So it seems like it's in the timing?
 

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Sounds like you've may have lost your fuel pump? Do you have fuel pressure at the rail? The back firing before it died could be it running really lean while running out of fuel. Since you have replaced the obvious... I'd look at fuel.
Good call or a clogged fuel filter. What happens when you attempt to start it? Does it just keep turning over or does it start and immediately stall? Etc.
 

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Can you determine it's getting a spark? CAn you pull a plug and then ground it and have someone crank the ignition to see if there's a spark?
 

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Discussion Starter #13
Good call or a clogged fuel filter. What happens when you attempt to start it? Does it just keep turning over or does it start and immediately stall? Etc.
It just turns over. Every now and then it will backfire will cranking
 

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Check two things
First with cap removed does rotor spin when cranking (if not busted timing chain unlikely but has happened)

Next check compression if low likley have stretched timing chain that jumped and now cam not timed correctly with crank
 

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Discussion Starter #16
Can you determine it's getting a spark? CAn you pull a plug and then ground it and have someone crank the ignition to see if there's a spark?
It's getting spark. I can't tell if it's sparking at the right time or not though
 

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Discussion Starter #17
Check two things
First with cap removed does rotor spin when cranking (if not busted timing chain unlikely but has happened)

Next check compression if low likley have stretched timing chain that jumped and now cam not timed correctly with crank
It spins because it sparks. Is there anyway to check timing?
 

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Don't think that will work spark is timed off crank angle sensor so cam out of time would not affect spark crank timing unless so far off distributor bug points at wrong plug wire

You should do a compression check because if valve timing is off crank timing compression will suffer

Or just open up the front and inspect timing gear marks

If you got starter spin spark and fuel sudden not running is most likely slipped timing chain

How many miles on engine?
 

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Discussion Starter #20
Don't think that will work spark is timed off crank angle sensor so cam out of time would not affect spark crank timing unless so far off distributor bug points at wrong plug wire

You should do a compression check because if valve timing is off crank timing compression will suffer

Or just open up the front and inspect timing gear marks

If you got starter spin spark and fuel sudden not running is most likely slipped timing chain

How many miles on engine?
I'm not sure how many miles. It was a reconditioned engine. So at least 20,000 since the new engine. I cracked the manifold and burnt a valve not long after I got it. It pecks some. But when it's cranking it doesn't sound like anything is broke in the engine. A jumped chain sounds like the most likely problem
 
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