ozmike00

I can't get my pressure turned down below 47 48 psi what am I doing wrong?

Bob88GTA

iTrader: (2)

which way are you turning the screw? CW is more, CCW is less

ozmike00

I can take the bolt all the way out and still not get below 47

Bob88GTA

iTrader: (2)

Ummm, that's not right. What do you get when engine is running with vac line pinched?

ozmike00

Pinched? With vac ref unhooked a get between 47 48

Bob88GTA

iTrader: (2)

Is your diaphram ok in it? (Had to ask)

ozmike00

Yes it's brand new bought it with the regulator

Bob88GTA

iTrader: (2)

???86 firebird GTA 350 TPI??? They didn't make the GTA till 87....oh well

what pump do you have in the tank? Stock, Walbro 255lph, 340lph???

Something aint right

Need a fuel guy here....

Bob88GTA

iTrader: (2)

Call Southbay

Bob88GTA

iTrader: (2)

See below in RED

Diagnosing Your Fuel System

Description and Diagnosis

If you are having fuel pressure-related problems, use these tests to narrow down the problem. You will need a fuel pressure gauge. You can either make one, using the instructions on the Make A Fuel Pressure Gauge page, or you can buy one for between $20 and $40. They are available at most larger auto parts stores. The better ones have brass fittings, bleed valves (to relieve the pressure), and metric adapters. Here you can see a picture of mine.

Check fuel pressure using a fuel pressure gauge. Connect it to the fuel rail service valve on the fuel rail or by installing a "T" fitting between the fuel supply line and the fuel rail, as described on the Make A Fuel Pressure Gauge page.
Turn the ignition key to "run" (engine off). The pressure should rise to about 34 psi to 38 psi for 1984-1985 N/A engines, 13.5 psi to 15.5 psi for 1986 and up N/A engines, or 53 psi to 57 psi for turbo engines. Try cycling the key once or twice if it is low. If you still can't get the pressure up this way, don't worry about it for now. Your battery or wiring may not be strong enough to power the pump without the engine running.
Watch the gauge. The pressure should hold. If the pressure drops quickly, there may be a leaking fuel injector, a bad fuel pressure regulator, or a bad check valve on the fuel pump. If the pressure is high, the fuel pressure regulator is bad or the fuel return line is somehow blocked. Don't worry about low pressure at this point.
Start the engine up. The fuel pressure regulator is designed to maintain a constant pressure on the injectors, relative to the intake pressure (or vacuum). There will be a vacuum at idle and the pressure will drop. If you have a vacuum gauge, you can verify this. For each inHg of vacuum at the manifold, you should see a 0.49 psi drop in fuel pressure. So at 15 inHg of vacuum, you should see about 47.6 psi of fuel pressure.
Remove the vacuum line from the regulator. The pressure should rise back to its atmospheric level (about 36psi for 1984-1985 N/A, 15psi for 1986 and up N/A or 55 psi for turbo). If the pressure is low, there may be a fuel flow problem due to a dirty fuel filter or a worn fuel pump. Be sure to connect the vacuum line back up!
If the pressure measures OK, try revving the engine with the vacuum line hooked back up. The pressure should rise to match the changing manifold pressure (a vacuum gauge or boost gauge for turbos is helpful), keeping a constant pressure difference between the two.
If the pressure is OK while parked, you will need to try driving around with the gauge attached. With a long enough hose, you can run the hose through the back of the hood and clip the gauge to the windshield with the windshield wiper. You will also need a vacuum/boost gauge to compare the readings.
If the fuel pressure drops off at higher engine speed or while driving, there may be a fuel flow problem or a bad regulator.
For information on upgrades, see the Upgrading The Fuel System page.

ozmike00

My rpo codes say it's a ws6 gta TA car so idk. ..

Anyway I have checked my return line frome the regulator all the way to the tank and I have no restrictions and as far as I know it has a stock pump

Bob88GTA

iTrader: (2)

I'm stumped on the AFPR


For your reading pleasure...

http://www.gtasourcepage.com/newauthentication.html

ozmike00

Thanks I'll check it out

southbay08

Hey ozmike00 why don't you give us a call. Let's see what's going on


516-442-4707

someone972

iTrader: (2)

Not to hijack the thread or anything, but I had a question on this line in the diagnosis procedure Bob88GTA posted.

Shouldn't this be the other way around, where the pressure reads lower with the vacuum line hooked up? I just want to make sure my understanding of the system is correct since I will also be installing a SouthBay AFPR soon.

ozmike00

Yes you are correct

ozmike00

I called them and they said I'm missing a metal ring that goes under the fpr
And above the diaphragm that should have been there with the stock fpr. Does this sound right? I never removed it from the stock setup, could it have Been missing already?

Bob88GTA

iTrader: (2)

YES