95stang

After install, went for test drive and it was like the gauge/FMU saw little boost (.3# & 44 psi). Both are on the boost side, and when I hooked a compressor up to gauge it read 16#'s so it's wired right. Also applied vacuum to by-pass valve and it opened. Is that how it's supposed to work? Any ideas what's wrong? Thanks.

callmecobra

i was unaware that kb had an fmu? i thought they all ran off a boost a pump

95stang

They have both (unless you have large enough injectors). Anyway, I still have to wire the boost-a-pump...still shouldn't there be boost showing on either the boost gauge or FP gauge when the FMU sees boost?

callmecobra

ide like to help you out but im not sure by what you mean when you say "the fmu sees boost"...but ide wire the bap and see what happens....

callmecobra

but to be honest i didnt think kb's used fmu's....i thought on all return style fuel systems, kb utilized the bap in conjunction with an adjustable fpr, to raise fuel pressure, instead of an fmu.

95stang

I think I'll try simulating boost at idle on the FMU (try applying a hand pump to see if FP gauge goes up). I'm hoping it's faulty boost/FP gauge (or wiring) because when I'm at WOT my air/fuel gauge reads .8 and above so as a whole each bank has a good reading and not lean.