Start it off with the basics, 78 F100 with a full crownvic frame, and a 4.6 2V engine and the stock 4R75W trans, 80 lb siemen deka injectors, stock fuel rails, stock fuel system. Blew up my first engine because I ran out of MAF with a turbo, increased intake size and changed position of the waste gate because of boost creep.
Fast forward, new engine in, scale maf tables a little, everything else is the same, fuel pressure is all over the place, 35-42 PSI randomly, on the first engine it would hold a steady 39. Figured it could be the returnless fuel pressure rgulator, changed it to a known good one, same issue, changed fuel pump to a 300 LPH Deaschworks, same issue.
Now just cruising down the road at 1500 rpm or so, the fuel pump will randomly spike to 75 psi, then go back down. I found the fuel voltage going from 2.79 to 4.79 in the scanner at around 4 minutes.
My question is, what parameters control fuel pressure voltage in the tune, maybe something is off, I've double and triple checked wiring, even though I never got to close to touching it during the engine swap other than I unplugged the fuel pressure regulator on the rail.
Tune and scan included. 19-11-30 21-04-02.hpl73 F100 4 inch tube 19.hpt
Reply With Quote