Originally Posted by
rsicard
Dave: The ECM is a 16197427 with BJYB binary loaded into the Flash chip. I suspect that there may be a vacuum leak between the throttle body and 4 barrel adapter or between the 4 barrel adapter and the 4 barrel manifold. The adapter plate is steel and 1/4" thick so the holes are threaded for the bolts with the 454 throttle body with supposed 65 Lb/Hr cop car injectors. They came unmarked to I really don't know the actual flow from them. I did not drill into the 4 barrel manifold for the TBI bolts. At this configuration, the open loop runs at 10 - 11 AFR as read on a Innovate Motorsports LM-1 and wide band sensor. Apparently when up to temp and going into closed loop, after a short amount of time, the AFR goes from 10 or 11 to greater than 15,, 16, 17 and then the engine dies. Also the idle is very high approx 1900 RPM. There is NO idle adjustment screw on the 454 throttle body. This has repeated 3 times already.
Next step is to drill clearance holes in the 4 barrel manifold for the throttle body bolts which at present have many washers that do not allow projection into the 4 barrel gasket between the manifold and the adapter. Then apply sealer to the 4 barrel gasket and to the throttle body gasket to make certain there are NO vacuum leaks.
Then run the engine again with the same binary. Also have a factory binary for the Vortec with TBI for export trucks. May try the latter binary later.