2003 no start/spark - JeepForum.com
 
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post #1 of 6 Old 09-17-2021, 06:04 PM Thread Starter
JeeperYJ95
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2003 no start/spark

So I'm helping a friend with their 2003 TJ 4.0

They hit a bump/Pothole about a month ago going about 20mph and the jeep stalled out and died. Another friend looked at it and ended up replacing the computer after a couple of weeks. After replacing it, it fired up and ran around the block and died again. I went over and looked at it this evening. Throwing a couple codes, but appear transmission related.

P0891
P0755

I unbolted the block holding the plug wires on and wedged my ignition tester on one of the boots. When we turned the key, I didn't get any spark.

Looking for opinions on where to start troubleshooting the spark issue.

I don't think there are knock sensors on these. Maybe crankshaft position or camshaft sensor??

Thanks!!

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post #2 of 6 Old 09-18-2021, 05:17 AM
jtec
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P0891 - trans relay always ON
P0755 - 2/4 solenoid CIRCUIT

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #3 of 6 Old 09-18-2021, 05:47 AM
jtec
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Keep you original PCM!!

When you turn key to run/on
Does the CEL come on @ 2 seconds then go out?
>> If yes -
is there 12v to injectors?
Do the injectors pulse as you crank engine?
Is there fuel pressure? post PSI.

Lets try this - as someone tries to start jeep spray some card cleaner or start fluid* into TB - did engine start and try to run on spray - yes or no?

Is thee a POS remote starter or 'kill' switch ?


* second choice, go easy its called boom boom juice for a reason.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #4 of 6 Old 09-18-2021, 07:01 AM Thread Starter
JeeperYJ95
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I don't think those codes would cause no fire though, right? I didn't check fuel pressure because I wasn't getting sparked so I stopped troubleshooting there....
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post #5 of 6 Old 09-18-2021, 07:48 AM
jtec
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MY THOUGHTS WERE - what a PIA checking the coil output with a coil rail and there are some basics I added - A reason to the madness
The CEL ? Is PCM powering up.
The inj for 12v Is the ASD energizing the systems down stream. easy place to check.
Fuel pressure a BASIC - and will confirm fuel pump esp after hitting big bump.
Those codes being trans issues - That is why I asked if you have the old PCM.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
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post #6 of 6 Old 09-18-2021, 09:37 AM Thread Starter
JeeperYJ95
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I do still have the original pcm...
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