Backfire and engine miss

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  #1  
Old 08-25-2010, 07:44 PM
gadmhahn's Avatar
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Default Backfire and engine miss

Okay guys I am at my wits end here...

I have a 1980 Z28 camaro with a 3 month old brand new 383 dtroker motors in it.

Specs:
Cast Eagle Crank
Forged rods and pistons
edelbrock performer top end kit (heads, cam, intake)
Holley 750 double pump carb

So here is what is happening.
About 3 weeks ago i started burning the number 6 cylinder plug wire. i changed it and it burned again. every time i would stop at a red light the car woudl backfire from the passanger side tail pipe. so i finally took the header out and put a dent in it. problem solved. or so i thought. The car began to bike fire and miss like crazy. We ended up changing the wire boot and put an HEI heat sleeve on the wire. it still was doing it so we changed the wire and it didnt go away. I changed the ignition box to a MSD 6AL as i was only running a 6A at the time. It got a little better but eventually came back (like 5 minutes later) and started doing all of its crap again. now we are looking at many other things. I changed the wire back to the MSD wire and we re-did the timing on the car. ran good until about a mile down the road and it started missing and Backfiring again. so i just changed the cap and rotor todaya nd its running absolutely terrible. I cant even get it out of the drive way now. it has no power and jsut backfires like a shot gun all of the time.
I was thinking it might be the ignition coil, but everyone is telling me that all that does is provide sparkto the distributor.
Any chance that the Distributor is bad now, or something else? All of the wiring is correct and nothing has been changed on the car up to the point when it starting running bad.

Any help from anyone would be so very much appreciated. I am ready to set this damn car on fire. Spending $5000 on a brand new motor and not being able to drive it is absolutely crap.

Thanks in advance for the help.

Matt
 
  #2  
Old 08-25-2010, 10:27 PM
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Maybe you have to torque your bolts (heads, intake etc) back down to spec? maybe your full of carbon? just a couple thoughts. I'm sure someone knows more about it than me and will chime in soon, but don't worry lots of knowledge here you'll get her running right, don't get stressed (i know it blows though).

Joe
 
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Old 08-25-2010, 11:03 PM
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sure sounds like a ignition modual.
 
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Old 08-26-2010, 10:39 AM
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the ignition box is from a friend of mine. It was in his car for 2 weeks and otherwise is brand new. I am not wondering if its the ignition coil. people say it is and otehrs say it cant be because all that does is provide spark to the cap...
 
  #5  
Old 08-26-2010, 12:54 PM
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Start with the basics. What tests have you done so far? Do as many tests first, as they are cheack/free, then start a shoping list. Also check everything. I would start with the timing, could be retarded.
 
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Old 08-26-2010, 01:03 PM
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timing has been checked. Its right where it needs to be. cap and rotor are brand new as is the msd box. plug wires are 2 months old as are the spark plugs. going to run a compression test tonight after i get out of work. However, this doesn't seem tike a compression issue as it does more of an electrical problem.
 
  #7  
Old 08-26-2010, 01:32 PM
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It never hurts to conduct free tests. If the ignition system is all new.... might be something else.
 
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Old 08-26-2010, 07:34 PM
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so when you put in a msd ignition you do away with the ignition modual/chip inside the distributor? or have you replaced that as well. ive never used a msd setup so i dont know.
 
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Old 08-26-2010, 07:46 PM
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It's an msd distributor. There is no chip on it. It's on the ignition box.
 
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Old 08-26-2010, 07:47 PM
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ok, live and learn thanks
 


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