grabbem88

mine is a billit.....had to send it out for repairs........how does that play into fuel pressure??

91LXstanger

The vacuum and fuel psi is like a/f ratio. U need an almost even amount or u can start to have problems.

grabbem88

my msd has a part#8456 what was yours?

Justanother5.0

hey bro... can you get a fuel pressure reading with the car under load? it kinda sounds like the fuel pump isn't able to maintain enough flow to keep the pressure up and meet the engine's fuel needs... although I really can't explain why the pressure is able to hold with no vacuum to the regulator... that doesn't make much sense.. but ya never know

You said you didn't see anything on the wideband.. did this problem start after your dyno runs?

I say you get a reading under load.. and if its dropping off look for a problem at the pump.... or maybe a plugged pick up screen on the pump or something.

grabbem88

thats what i'm leaning towards....pick up screen,maybe an internal leak.....maybe i cooked the newer pump???
think my fuel lines are too small causing vapor lock under load??
this has been going on since aug. and yes and nothing looked odd??????

grabbem88

what about the fuel pump relay??? god people....where are the brains at??

89stanglx

So with the vacume off the regulator it holds at 42 even reving it? With the vacume on the regulator the pressur drops revving it. It has to be a vacume problem? No vacume means unregulated pressure correct? To much vacume would be not enough fuel pressure. Im really asking questions my self i dont meen to be stearing you in a wrong direction.

grabbem88

i wish one of guy's was close by....i wonder if i take pics will that help?

nemethjames1

ya take pix

grabbem88

it's dark now...i'll do it in the morning though.