Generation III Internal Engine 1997-2006 LS1 | LS6
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Old 05-30-2006, 01:04 PM
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okay guys i need some help. i pulled my motor and trans out and put a replacement in. no i am not getting and fire to the plugs. on both sides of the coil pack wiring harness i have 2 hot wires on both sides of the car. i replaced the cam and crank positioning sensors and still no fire. i know the pcm is seeing the crank because the fuel pump will run for 2 seconds after cranking. let me kno what you guys think could it be a ground issue??
if so maybe someone could give me the ground layout for the engine bay.
thanks alot. i hope to get this solved and started. it has been down for 4 months.
Old 05-30-2006, 02:39 PM
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so whats up no help?
Old 05-30-2006, 05:40 PM
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hello? anyone with any knowledge about this?
Old 05-30-2006, 05:42 PM
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What year and model?

What motor?
Old 05-30-2006, 05:45 PM
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98 trans am LS1 A4 stock tune stock pcm. i think it might have something to do with ground wires but not for sure. could that keep it from starting or keep it from getting fire to the plugs?
Old 05-30-2006, 05:51 PM
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Well I would say that if the starter motor turns, you got ground.

However, there are a bunch (3 at least)on the rear of the heads.

Was it running before you took it apart?
Old 05-30-2006, 06:01 PM
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yeah i had spun bearings. if the grounds are not on the back of heads would that keep it from running or getting spark to the plugs?
Old 05-30-2006, 06:27 PM
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anyone with an answer. need help bad please
Old 05-30-2006, 06:48 PM
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Possibly yes. Just take your time and look everything over real carefully. It is probobly something you overlooked and is staring you right in the face. I know it is frustrating, you will get it just walk away if you have to.
Old 05-30-2006, 06:52 PM
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For one, the PCM doesnt need to see the crank turning for the fuel pump to engage, all it needs to see is the ignition in thw run position. Then if the PCM sees no cranking from the CKP sensor, it will disable the fuel pump relay.

It could be a ground issue. Check to make sure you have the ground wires bolted tight to the back of the head. Also make sure the ground wire down by the alternator is hooked up and is tight.
Old 05-30-2006, 07:05 PM
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so if i dont have the grounds bolted to the back of the heads than that could be why i dont have n e spark
Old 05-30-2006, 07:08 PM
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Originally Posted by 98slowt/a
so if i dont have the grounds bolted to the back of the heads than that could be why i dont have n e spark

I believe that is so.
Old 05-30-2006, 07:10 PM
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if after hooking up your grounds you still have problems. Check to make sure that you did not pinch any wires when installing the transmission. We had an issue at one point where the cam-position sensor got pinched between the tranny and the block, which made it deliver no spark.
Old 05-30-2006, 09:58 PM
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Originally Posted by 98slowt/a
so if i dont have the grounds bolted to the back of the heads than that could be why i dont have n e spark
Yes...the PCM receives some of it's ground from the back of the head. The PCM grounds the coil circuits to initiate the spark...if the PCM grounds are bad, you will have a car that wont start.
Old 05-31-2006, 12:11 AM
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has anybody else had this problem before?
Old 05-31-2006, 06:21 PM
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nobody has ever had this problem before
Old 06-01-2006, 09:37 AM
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okay i pulled the intake and found three wires on the driver side disconnected. so i grounded them and then reinstalled the intake and the car started. thanks guys for everyones help.




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