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Discussion Starter #1
whenever i rev the car up to high it backfires. sometimes very loudly, sometimes its just like the fuel cuts out and it just jerks. I know its not the boost cut out because i have an aftermarket boost guage and im only making about 10 boost. the car is a 87 shelby z the only thing i have changed is that it has a bigger warlbro fuel pump. what would cause this problem.......please help
 

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How high are you revving it? Most TD's have a rev-limiter at either ~6200rpm for 2.5s or 6650 for 2.2s. It works just like the overboost cut. Might also be an ignition miss from a problem with plugs, wires, coil, etc if you are below the rev-limiter. Could also be too rich. Not as likely for a backfire through the exhaust, but it COULD be too lean. If you have too much boost below a certain rpm (~3000rpm IIRC), and depending on ECM, it will cutout. Usually you have to run a grainger and floor it in 4th or 5th to make this happen.

In short, start eliminating things from the list above until your problem goes away.

Good luck and welcome to the world of fixing TD's.
 

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Discussion Starter #3
im pretty sure its not hitting the rev limiter, but its kind of hard to tell since my tach when it gets over about 4k just starts going crazy all over the place, ive changed instrument clusters and the same thing happens........actually im sure its not the rev limiter because it has happened to me in 5th gear and i wasnt going that fast:cool: The one thing i forgot to mention is that it has a free flowing exhaust with no muffler that and the warlbro fuel pump are the only things done to it. Ive changed the plugs, wires, cap and roter, and coil. I looked at the plugs and they look fine.
 

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87turbodance said:
If your tach is gong mental it sounds like it could be a hall effect pickup problem
It's definitely an ignition problem then. Any time I've had tach problems it was the coil. Try a different ignition coil. Also make sure that the + and - connections to the coil are correct. If they are backwards the car will run like ass.
 

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Discussion Starter #8
thanks ill have to try switching the coil and see if that changes anything........it makes sense it may be something with the ignition because it seems like it starts missing a little before it backfires.......
 

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its fuel related. i had that problem twice. once it was that my FPR was stuck at 45 psi, the other time was when my injectors were pushing out way too much fuel. check your plugs.
 
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