C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Damnit...help!!

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Old Aug 3, 2009 | 05:51 PM
  #1  
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Default Damnit...help!!

Alright I just finished wrapping up the corvette.

I took it apart and
-ported intake manifold base
-installed as&m runners
-installed ported plenum
-relocated IAT (plenum had a blockoff plate where IAT is)
-eliminated CSI

Now when i try to start it, it cranks and backfires through the exhaust..i heard that when it backfires through the exhaust that the timing is too far retarded, so i advanced the timing a bit and it backfired through the intake. it was REALLY loud, not like it did when i first got it where they were minor backfires.

Is the timing really that sensitive? When i move it the slightest bit it backfires through the intake, if i move it back it backfires through the exhaust.

SAVE ME!@!!!
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Old Aug 3, 2009 | 05:58 PM
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it's also possible the spark plug wire is on the wrong plug... i actually made that mistake on another car...
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Old Aug 3, 2009 | 06:39 PM
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I numbered the spark plug wires when I took them off, but I suppose I could have misplaced some.
Any other ideas?
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Old Aug 3, 2009 | 06:53 PM
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did you adjust the valves?
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Old Aug 3, 2009 | 06:58 PM
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Originally Posted by Pwnage1337
I numbered the spark plug wires when I took them off, but I suppose I could have misplaced some.
Any other ideas?
i guess just check and re-check your timing. i'm an LT-1 guy and don't have to check timing and such, so i'm not real good in that respect... sorry...
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Old Aug 3, 2009 | 07:20 PM
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Double check to make sure the dist. is in right and the firing order is correct.
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Old Aug 3, 2009 | 07:27 PM
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Sounds like timing could be off. Bring #1 cylinder to TDC compression stroke check rotor position should be pointed @ #1 cylinder and check mark on harmonic balance should be 6* on tab. If necessary pull and reposition dizzy. Firing order 1-8-4-3-6-5-7-2 looking from front of motor clockwise on dizzy, moving the dizzy itself counter clockwise advances timing

Last edited by floridamale; Aug 3, 2009 at 07:34 PM.
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Old Aug 3, 2009 | 07:48 PM
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Thanks guys, ill work on it tomorrow and keep you guys posted.

You have to adjust the valves???
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Old Aug 3, 2009 | 07:54 PM
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Thanks guys, ill work on it tomorrow and keep you guys posted.

You have to adjust the valves???
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Old Aug 3, 2009 | 08:02 PM
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Thanks guys, ill work on it tomorrow and keep you guys posted.

You have to adjust the valves???
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Old Aug 3, 2009 | 08:18 PM
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Unless you did something to them they should not have to be adjusted, dosen't sound like you messed with the heads so they should be OK
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Old Aug 3, 2009 | 08:57 PM
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Yep sounds like the Dist. wasn't put back right do the #1 thing and listen to it roar !
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Old Aug 3, 2009 | 09:49 PM
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with floridamale. Distributor and wire issue.
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Old Aug 4, 2009 | 02:34 AM
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Thanks guys!!
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