spudz

My boss has a 92 notch 5spd.. He just installed a adjustable regulator and we can't adjust it down. It keeps the guage peged out at 60psi and it runs like ****, runs rich and falls on its face... The car has a upgraded fuel pump, I wanna say a 77mm TB and a 75 MAF?? 30psi injectors, gt40p heads and gt40 upper an lower intake. WHY can't we get the fuel pressure down??? And it runs terrible, it lopes real bad and if you floor it while you are goin down the road it will almost shut off. I am lost I dunno what to tell him... I blew the return line out thinking maybe it was stopped up but it was fine. What do you think?

Tims 88GT

humm maby a vaccum leak? what kind of regulator did you put on it? also i think the 30's are a lil big

spudz

yeah 30s are big but its not my car lol... Ummm....am I suposed to have any vac at idle at the reg?? if so.....then thats the prob since there is no vac.... also I pulled a vac on the reg and it didn't hold pressure... I would think that the diaphram in the reg would hold pressure or is it suposed to bleed off??? I mean it will pump up and just leak down... I dunno. I am just tryin to help him lol.

roughneck9725

Yes, you should have vacuum at the regulator (assuming it is a vacuum/boost referenced type). If no vacuum is present, then you will have high pressure. You should still be able to adjust it under 60psi though. First, fix whatever the problem is causing your no vacuum situation and then see what pressure is at idle.
There is some info missing in your question so I will give a step by step diagnostic procedure to cover everything I can think of.
First, disconnect the return line at the fuel tank and run it into some type of catch can. run the pump and adjust the regulator down as far as you can, see what the pressure is. Next, disconnect the return line at the regulator and see what pressure is (use a LARGE diameter hose to direct fuel into a catch can) and see what the difference in pressure is from the first test. If you see a big difference, the return line is a restriction. This could mean a blockage in the hose OR, when he put in a higher volume pump he didnt think to change out the return line to a larger diameter, which will not handle the volume. If you do this and still cant adjust the pressure down I can only think of two problems. You arent adjusting it right or the regulator is no good. Hope this helps some and if anyone else can think of something I missed please jump in.

angcobra

If I make the assumption that pressure was being maintained by the old regulator, then line restriction, vacuum, and such does not seem likely, most likely would be adjusting in wrong direction or bad regulator.

spudz

OK I GOT THE PRESSURE DOWN... Seems the BBK regulator was bad right outa the box, replaced it with another one and it was able to be adjusted down. SO he has got the fuel pressure fixed and the car will idle good but it STILL falls on its face when you mash the gas. If you ease on it, you can accelerate. But still cuts out... Never EVER messing with BBK again....

angcobra

may still have pressure too high. Have the A/F checked with wide range or on dyno.

88BlueGT

Well, I know you already said that its not your car but I would def tell him that he does not need 30lb injectors AND I his tb is waaay to big. It may be a 75 that you are talking about also because Ive never heard of a 77 (could be though,,, not sure). But his TB and inj. are huge. He has enough fuel for a blower on that car.

luckythirteen13

is the maf calibrated for those 30# injectors? even if it is, he should only be running 19's. the tb with those mods should be a 65mm

88BlueGT

Yea, def. The 19's will support 300hp so if he REALLY wanted to he could upgrade to the 24's but thats even unnecessary. And if he doesnt have anything calibrated that would be why his car is falling on its face. I would let him know all of this for him & his cars own good.