I am going to try a different base fuel map later and play with the idle throttle opening screw. The PF4 ECU has me ready to order a DBC LS swap harness, yank the PF4 ECU and harness and throw it all up on ebay along with the single plane intake that is already not being used. It is giving me the same issues it has had all along. The acceleration fuel is absolutely maxed out and it still has an extremely lean tip-in. The base fuel map has atleast 20-30% too much fuel in it during deceleration and at some cruising areas and 10% too rich globally resulting in large adaption numbers that are outside of the systems desired range. The map for a stock cam with ~18-20 in/hg vacuum had fuel trims of -50% in places, like really is a very mildly cammed 350 that hard for Edelbrock to dial in correctly??? The cam is so mild in this basic L31 350 it is pulling nearly 20 in/hg vacuum at 750 rpm. Cold engine, shift to reverse, stalls out. If the engine is hot, sits until it cools down to 100-140F, go to start it no throttle, it either floods out entirely or starts at an extremely rich, low idle then the IAC flares the idle up. The AC compressor also peeves off the IAC logic everytime the compressor cycles. Then add in the fact that the way Edelbrock setup the vacuum advance is absolutely horrible and identical to using the smog junk era ported vacuum emissions bandaid. Not enough idle timing and the vacuum advance setup can only provide ~10* more timing at 20 in/hg during cruising. ECU needs to be thrown back through the front door at the Edelbrock group, with a detailed spreadsheet of fuel trims vs map vs rpm and the a timing map detailed out in the same manner with note that says fix and return me.
I doubt the fuel map I am going to try changes much, but I am going to lie to the POS to try to get the base map leaner. It has a map calibrated for the same displacement and cam vacuum profile, except for use with a 58 psi regulator instead of the 43.5 psi unit I am running. They also have a map for 35# injectors rather than the 29# with the same displacement and cam profile. I am going to first try using the 58 psi map which should make the ECU believe it is controlling 33# worth of injector when it is actually controlling 29# worth. On paper should lean the whole calibration out 12.9%. My fear though is that it will make the already 16:1 tip-in lean spike even at slight throttle openings even leaner. If that fails to lean it out enough to even out the fuel adaption the 35# map should be 18.75% leaner on paper. There is also a 35# map for 58 psi that would be even leaner in theory. My hope is that the acceleration fuel is just some pulsewidth thrown into the calibration and not altered much in any of them, if I can get it leaned out a bit in the base map and not make the tip-in lean spot worse, it might actually help correct the lean tip-ins with the ECU not having to pull so much fuel in the overly rich spots.
This harness, L31 distributor housing for a cam sensor, some LS coils, the 24x reluctor already behind the timing cover and a P59 PCM on a speed density tune is looking like a great option at the moment.
This harness is a 5 wire MAF and a 1 wire alternator. FREE ADAPTER Connectors TO CONVERT Harness TO DELPHI MULTI 4.8 5.3 or 6.0) Injectors. All other sellers will give you 3 wire that you have to convert to 5 wire and ev1 injector connectors that u have to convert to delphi. Lots of extra costs...
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