Setting fuel pressure?

[JnJSpdShop]

Well just finished up helping a friend install a new accufab FPR, and clean up some vacuum lines under the hood. Now trying to set the fuel pressure is a bit strange. We get the vehicle to operating temperature, remove the vacuum line from the FPR, and plug it with my thumb. Then I adjust the FPR to 50 psi. Blip the throttle a few times, and make sure it is at 50 psi. Now replace the vaccum line and tighten down the locknut. Get in the truck and go for a ride and the fuel pressure is around 60-63 psi with no boost just cruising. I thought the vacuum line connected is suppose to drop the pressure, and then once in boost increase on a 1:1 ratio. The vehicle has an aftermarket fuel pump and 42. lbs SVO injetors. Any ideas?

 

[turbodog]

Have you re-checked FP with the vacuum hose removed? Does it return to 50 PSI? If so, I have no idea. If not, sounds like FPR failure.

 

[Loeryder]

Your thining is correct.
The vacuum should pull the fp down under 50.
at 0" of vacuum you shoudl see your 50PSI then it will rise from tehre at the 1:1 ratio. Every PSI of boost is 1 PSI of fuel.

I set mine with the engine not running and hook 12V to the fuel pump test lead on the firewall. Its a grey wire with a female spade terminal on it.
Should be just on teh pass side of the distributor tucked down in or behing the wiring harness back there.

That way you remove the vacuum from the equation and dont have to disconnect/reconnect vac lines every time.

 

[JnJSpdShop]

Have you re-checked FP with the vacuum hose removed? Does it return to 50 PSI? If so, I have no idea. If not, sounds like FPR failure.

I would hope it isn't a bad FPR because it is brand new. It does have an eletronic fuel pressure gauge. I am beginning to wonder if the sending unit is fobared

 

[turbodog]

It wouldn't be the first new FPR that ever failed. However, you're right not to trust the guage either without independant verification. A test guage at Autozone is about $40. Cheap insurance.

 

[GM TURBO]

I do mine the same way Jason does. It is much easier and probably safer also.

 

[turbodog]

Were you using the same guage during the setting process as when cruising?

Also, when cruising was the FP (even though 'way high) tracking up and down with throttle movement? Or was it pretty much 'fixed'?