Headers on...start but no run..help
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Joined: Jun 2007
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From: White Lake Michigan
Headers on...start but no run..help
So here's the situation. Finally installed the headers and go to start the car, it starts right up then dies. 
Let me tell you how the O2's are set up. This may be the issue. I used the rears in the front locations with flat to square adapters. Right to right, left to left, just like stock. The rear plugs are left open. Do I need O2 simulators for this to run? It's going to the dyno and they will tune them out so I thought no problem to leave them open...incorrect thinking, I'm thinking...Please get me straight !!!
Let me tell you how the O2's are set up. This may be the issue. I used the rears in the front locations with flat to square adapters. Right to right, left to left, just like stock. The rear plugs are left open. Do I need O2 simulators for this to run? It's going to the dyno and they will tune them out so I thought no problem to leave them open...incorrect thinking, I'm thinking...Please get me straight !!!
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From: Oklahoma City
St. Jude Donor '09-'10-'11-'12-'13-'14-'15-'16-'17,'19,'22
What all did you take out/apart?
It should run without the rears. I don't have any of mine plugged in I just have the holes plugged. You will get codes until they clear them though.
It should run without the rears. I don't have any of mine plugged in I just have the holes plugged. You will get codes until they clear them though.
Drifting
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From: Byron Center MI
I'm not sure where to start. I'm thinking of the last set of headers I helped put on.
It should run with out the O2 sensors. After all it did run and then died.
Does it still turn over but won't start?
Did you disconnect the fuel line?
Did you remove the coil packs?
Anything you disconnected I would double check.
If I were closer I would come over and help check things out.
It should run with out the O2 sensors. After all it did run and then died.
Does it still turn over but won't start?
Did you disconnect the fuel line?
Did you remove the coil packs?
Anything you disconnected I would double check.
If I were closer I would come over and help check things out.
Thread Starter
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Joined: Jun 2007
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From: White Lake Michigan
Far as I know we swapped the rear O2's for the fronts and used the adapters to go from square to flat. We left the rears open, just tied up out of the way. It's crazy, the car fires right up and 5 sec later....dies. That's why we were thinking we need O2 sim's to fill in the rear plugs.
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From: White Lake Michigan
I have no idea if it has thrown a code..won't run long long enough to see a check engine light, and I dont have an OBD2. Just trying to get it to run so we can get it to the dyno. One of the FAQ's in the header install thread @ LS1 how to said you will need O2 sims. We removed the coil paks, no fuel, starts instantly..then craps out....
Team Owner
Joined: Jan 2004
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From: NJ
Cank you have the front O2's crossed??
The rear O2's are reference for the cats only they do not effect the way the car runs. I drove my car for months w/ no O2's after the header install and prior to my tune.
The rear O2's are reference for the cats only they do not effect the way the car runs. I drove my car for months w/ no O2's after the header install and prior to my tune.
Last edited by Chevy Guy; Oct 25, 2009 at 07:50 PM.
Thread Starter
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Joined: Jun 2007
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From: White Lake Michigan
Chevy Guy,
My friend took it apart but from what I recall, where the front O2 were located, they are not long enough to go to the opposite side. I could rewire them opposite, but I don't understand. Am I missing a piece of the puzzle? Obviously !!!
My friend took it apart but from what I recall, where the front O2 were located, they are not long enough to go to the opposite side. I could rewire them opposite, but I don't understand. Am I missing a piece of the puzzle? Obviously !!!
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Team Owner
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From: NJ
Take a little break and clear your head. Go do something else for a while and go back to the car and start checking everything you touched for loose connectors. Maybe a vacuum hose got knocked loose?
Drifting
Joined: Aug 2004
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From: Dayton Ohio
I have no idea if it has thrown a code..won't run long long enough to see a check engine light, and I dont have an OBD2. Just trying to get it to run so we can get it to the dyno. One of the FAQ's in the header install thread @ LS1 how to said you will need O2 sims. We removed the coil paks, no fuel, starts instantly..then craps out....
Of the things I can think of, you might want to double-check:
- coil pack connections
- the driver's side engine ground that was removed
- for a massive vacuum
- front O2 connections
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From: White Lake Michigan
BanditDude,
Am i correct for the front O2's left,left/right/right? The driver side engine ground was installed in a different place but my friend says the path should be the same.
Am i correct for the front O2's left,left/right/right? The driver side engine ground was installed in a different place but my friend says the path should be the same.
Former Vendor
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From: Hazel Green, Wi www.doubledmods.com
St. Jude Donor '12-'13
Did you do a mail order tune by chance?
If so you might have to relearn the computer.
the process for this is to try and start car, it will die on you leave key on till security light goes off. Do this two more times then on the third it should start and stay running.
Thats what i had to do when i reinstalled my new computer. It actd the same. it fired right off then died.
If so you might have to relearn the computer.
the process for this is to try and start car, it will die on you leave key on till security light goes off. Do this two more times then on the third it should start and stay running.
Thats what i had to do when i reinstalled my new computer. It actd the same. it fired right off then died.
Melting Slicks
Joined: May 2000
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From: Brentwood TN
I think the front O2's are wired left connector to right O2 and right connector to left O2. I'll get up under my car and check. Maybe someone else can step in and confirm if this is correct or not.
Charlie
Charlie
Drifting
Joined: Aug 2004
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From: Dayton Ohio
I agree that a different mounting point for the ground should not be an issue. It just needs a strong path.
Team Owner
Joined: Jan 2004
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From: NJ
This has to be something silly. It actually sounds like the security system is killing the car.
Do you have another key to try?