The subject is a 1984 Porsche 928 5.0L v8 with a Vortech supercharger controlled by a GM1227749 ECM. I ran a similar configuration for several years and many track hours, it was running pretty well until I lost compression in 2 holes last fall. This spring I built a new engine... bigger throttle body, bigger cams, extrude honed heads, bigger injectors, headers, 3.5" single exhaust.
It's starting and idling pretty well right now, revs like crazy when I blip the throttle at a stand still, but when I open the throttle while rolling it goes lean and starts coughing. If I back out and use a couple percent tps it will accelerate but goes lean with more throttle and coughs and bucks if I give it much more.
I've increased the fuel (globally increasing base ve vs map vs rpm table) until it's real rich at idle, puffs a cloud of unburned fuel when I rev it, no real change in behavior. I've increased PE related fuel a couple of times without improvement.
Where should I be looking to fix this? Am I in the right area tweaking the PE tables? Any assistance would be appreciated, I'm relatively new at tuning. I posted a scan at:
http://home.comcast.net/~p-928/rob-3.adl
It's kind of big (400k or so) with several easy passes through the gears
and quite a bit of more or less steady state driving.
Thanks,
Bill
New blown 928 engine, help!!
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