Well, To start It is a 1987 IROC that came with a 305 T.P.I. I pulled the engine and put a 1992 Vette 350 then changed the system to a S/D instead of MAF system. I had the Ecu retuned it was a great runner. I am in the planning on running a Vortech S/C and don't want the TPI system to fall flat on its face, So I bought a TPIS mini-ram with a B&K throttle body. Here is the problem.

One the TPIS mini-ram was installed the engine is constantly backfiring.
I bought new Ford 42lb injectors and retuned with no luck
Bought a new O2 3 wire to replace the 1 wire to help headers run in close loop
Bought a new distrib with ignition module and cap and rotor with no luck.
Checked the fuel rail pressure which is currently at 44lbs.
Running a remote accel supercoil which doesn't appear to be bad.

Ran TTS datamaster and am getting constant knock counts above idle
Engine still back fires especially when I put a load on it (Driving it)
Datamaster is showing that it is pulling spark retard on it.
BLM's at idle are around 130. VE master can correct but it still back-fires.

I did find a few spark plug wires that were melted because they were touching the headers. I did change them but now they are mismatched. The problem still didn't correct the back fireing though.

This engine is freshly rebuilt and didn't have all the knock counts or backfireing while running the TPI intake. What else should I check to correct this problem.

I have been running a cyberdyne digital dash in this car so the VSS isn't showing in the Ecm. Should I run to wires in the ecm so can detect speed and use all the functions available?

 

Backfiring is typically a timing issue. Which would make sense if you're getting knock and the computer is trying to back timing out. You would have taken the distributer out to replace the intake, is it possible your off a tooth or 180 degrees out?

 

We have checked the timeing and fully retimed the engine for about the 3 time. Putting NO# 1 up on compression stoke and at TDC on Harmonic Balancer. Then disconnecting ALDL and setting timing at 8 degrees btdc. I have been trying to understand why my friend wants to put at 8 instead of 6. That hasn't made a bit of difference though. Still back fires no matter at 6 or 8. There might have been another problem that we ran into. The TPIS was match ported with Felpro gaskets # 1205 to the heads. I think that when the TPIS intake was installed it was using stock intake gaskets that are considerably smaller than the part that was match ported. I bought new #1205 intake gaskets as I think that might be part of a problem also.