Burning Rubber

iTrader: (1)

I have a 96 lt1 that is sluggish and doesnt run well under load. It is freshly rebuilt but I added trick flow heads, forged pistons and forged rods. My old set up is in my sig. It has good spark and compression. The fuel pressure is only at 38 lbs though. When I remove the vacuum line the pressure does not change. I also had an adjustable regulator at one point and when I adjusted it the pressure never changed. I just put a new fuel filter on it and nothing changed. So I guess the questions I have are: Is 38lbs enough fuel pressure or is that too low? Could the fuel pressure not changing at all even with the regulator at different settings mean the fuel pump is bad? And also it hasnt been tuned yet. I was wondering if some of the sluggishness could be because of the tune?

RamAir95TA

iTrader: (2)

38#s of pressure is fine really. Make sure the vacuum line for the regulator isn't plugged though.

Hard to tell if the tune is the problem. Only your tuner and some dyno-time can tell.

Burning Rubber

iTrader: (1)

I put my finger tip over the end of the vacuum line and there was vacuum. So I am assuming that the line is not plugged.

Burning Rubber

iTrader: (1)

Will the fuel pressure need to be adjusted up for nitrous?

*CAMARO*

No, don't adjust fuel pressure for nitrous. You can change jets sizes to adjust to your fuel pressure. I do recommend a fuel pump upgrade and fuel pressure safety switch however.

Burning Rubber

iTrader: (1)

An upgrade from a 255lph? What would I upgrade to? Do you think my pump could be on its way out? It only has about 5,000 miles on it. But it has been run out of fuel a few times. I already have a safety switch.

*CAMARO*

Sorry, I did not see that you have a 255. That and the fpss should be fine.

GM PHASST

Sounds like ur regulator could be stuck on one setting internally.
Can u maybe rig up some type of adapter and attach it to the fuel feed line?
If so, check ur pressure there.

Burning Rubber

iTrader: (1)

The feed line at the pump?

Burning Rubber

iTrader: (1)

Or just anywhere before the regulator?

Tbird232ci

iTrader: (4)

How much voltage do you have at your pump?

97lt1camaro

iTrader: (3)

When my pump was going out i was only getting 22 psi at WOT and it still pulled like a bat out of hell.

Burning Rubber

iTrader: (1)

I dont think I mentioned this earlier, but I also pinched the return line closed and the pressure still stayed at 38 lbs. I will have to check the voltage to the pump and check the pressure before the regulator. I have had two different gauges and two different regulators on it and the pressure always reads the same unless I give it throttle. I'm wondering why it never changes?

Tbird232ci

iTrader: (4)

If you pinch the return line closed, that will eliminate your regulator being bad.

I see you have a 255lph pump, but did you do the fuel pump hotwire kit?

defaultexistence

iTrader: (11)

any way you look at it your fuel system is not working properly..it should rise in pressure with throttle ,that cam set up is also going to demand more fuel and air over stock aswell as a proper tune. so there is no wonder its running shitty for several reasons..

Burning Rubber

iTrader: (1)

What is a hotwire kit? My pump is wired through a switch with a relay in line.

I thought fuel pressure was supposed to drop with throttle. It has a tune for a cam only cc 306.

Burning Rubber

iTrader: (1)

It needs a new tune. I know that. But I wanna make sure its right before it gets to the dyno. I am trying to make sure there are no underlying problems causing it to run shitty other than the tune.

quik95lt1

iTrader: (7)

just out of curiousity.........is the gauge good lol???? try a different gauge.....and also when you said you had an external pressure regulator on it how did you have it plumbed??? where was the regulator hooked up? and where is the gauge in the system, where are you trying to read the pressure??

Burning Rubber

iTrader: (1)

Its just an aeromotive adjustable regulator mounted and plumbed just like stock. I tried two different gauges with the same result. I am reading the pressure just after the regulator on that fitting on the fuel rail.

quik95lt1

iTrader: (7)

ok thats all good.........just wanted to make sure.........you may have a pump issue where its internally bleeding off pressure yeilding a non adjustable 38lbs........could even be that the plastic hose on the top has cracked or somehting.......do u have the trap door cut so you can easily get in the tank?? also just out of curiousity when was the last time u changed the fuel filter???