red04goat

i am working on a 2011 cts v, 85lb injectors, MSD BAP, and tuned for e85. The issue that I am running into, is that at idle, I am showing high fuel pressure(78-84psi) at idle. Any ideas?

red04goat

This is with the BAP installed post FPCM btw. Tried it pre FPCM and the car shut off, so I dont think that is correct.

punishmentcycle

iTrader: (6)

Sounds to me like the boost a pump is either wired incorrectly or it's bad and pushing voltage all the time.

red04goat

Thats what we thought at first, called MSD and they said it was a bad BAP, so we got a new one. All wires correctly installed and it works like it should at WOT, just at idle its all fucky

red04goat

Theres four wires: 1) positive and negative to battery 2) orange wire on signal out of the FPCM 3) red wire to fuel pump

punishmentcycle

iTrader: (6)

msd bap have never really had a good track record... kenny bell would be the way to go..40amp version.

with that said..does your msd have an adjustable hobbs switch for boost? if its turned down too low ive seen them pick up refference from just the atomphereic pressure. could be ur issue.. but it will work fine at wot because ur getting 17 volts at all times..itll also cause the high pressure when idling as the voltage never goes back to 14

punishmentcycle

iTrader: (6)

one more quick question... whats done to the car? are u under 700whp? if so the bap pump is not needed. my buddy is running 16 lbs thru the stock blower making 658whp and hasnt come close to a fuel problem.....yet

red04goat

The MSD has a MAF sensor in it so it reads vacuum and boost. There is a vac line running the length of the car. The voltage will not drop below 14.2.

its at 660whp but on e85, 85# injectors

vmapper

iTrader: (8)

The MSD pump booster has a MAF sensor? No it does not.
MAF requires FLOW through to measure 'mass' aka density so it would have a MAP sensor or Baro sensor.

Running a Vac line to the location of the Voltage booster is a stupid design. kink in the line perhaps? Rule of thumb, Always use wire for signals... I wouldnt have bought this thing for that design alone...

PW is controlled in the ECM for pump. If you have removed the MSD out of the picture, the next place I would look would be the tune.

punishmentcycle

iTrader: (6)

which msd do u have? i know there are a couple msd bap that can be computer calibrated just like tuning. lets u adjust the ramp rate and set max voltage... i believe even by gear. might have to look into that and get it adjusted

red04goat

yeah its a MAP, i had a senior moment.

red04goat

we have the 2351

red04goat

it wont adjust down in our computer. It wont go lower then 14.2. We can adjust it but it wont register in the car

punishmentcycle

iTrader: (6)

its never gonna go lower than battery voltage for saftey reasons plus thats the input voltage. something isnt right and id say u got another bad bap

red04goat

what are the odds that we would have gotten 2 bad BAP's? Like i said, this is our second one because the first was also bad.

vmapper

iTrader: (8)

Lets step back a step.
You are dealing with a PWM pump setup.
You are connecting to the FPCM not the pump itself correct?

I would have just upgraded the pump assembly itself ...drop in... so easy, many choices available.. remove all this voltage boosting all together.. but I guess that is here-say.

red04goat

correct, we are connected to the FPCM then FPCM to pump. There are a ton of cars that are set up the exact same way that ours is, using the same parts as us, and work flawlessly. I dont get it

punishmentcycle

iTrader: (6)

electronics are weird sometimes and like i said..msd hasnt had a good track record with bap's

ryridesmotox

^^^Truth I hate electronics so much sometimes.

red04goat

surely someone has encountered this problem, or they are ignoring the fact that there idle fuel pressure is 80psi