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Crazy Crossfire Problems

djbess

New member
Joined
Apr 25, 2014
Messages
2
Location
San Pablo, California, United
Corvette
1984 Red Crossfire Z51
When I got the car it had a small hesitation. After giving it a tune up. I discover little bit of water in the oil with a cracked head. Long story short now it has pro comp heads 190cc runners 63cc compression chambers. Lunati 280/290 .443"/.465" cam, lifters and timing chain, roller rocker arms, harden push rods, New injectors, diaphragms, cap, rotor, ign module, coil, TPS, MAP, O2, plugs, and wires.

The problem: When you stomp on it say go form 10% throttle to about 70% it will back fire then take off. This problem is intermittent. More likely from a stop. But does happen when your cruising.

The Next Problem: I though maybe the ECM was bad. So I bought a new remanufactured ECM popped my prom in it. And it won't start. While you start it the injectors wont pulse they just spray a continuous stream of fuel flooding the car. Swap the prom to the old ECM in and this doesn't happen. I thought maybe the remanufactured ECM was bad since I got it from ebay although it was unused. So I went to the local parts store and ordered a New remanufactured one and have the same problem. :mad
 
Did you swap the fuel chip along with the prom, I believe you did not see it when you took the prom cover off.
 
I may be thinking of an earlyer model but I thought the first fuel injected engines used a prom and a fuel calibrator. Later years they combined them to a cal-pack.
Found this on goggle
http://www.corvairnut.com/Images/1227747.JPG

fuel calibration on the left, PROM on the right
 
With the changes you have made, what have you done to the calibration? Are u still running the stock ECM?
 
When you say backfire, do you mean from the throttle body or from the tail pipe? If throttle body, the backfire is caused by a lean condition. If from the tail pipe, it will likely be timing related. :)
 

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