For those running 30-35psi of boost.. hoses or ?? leaking.

[KEVINS]

Yea, the MAP wiring was redone by splicing into the grey wire behind the glove box when I installed PL and the new MAP sensor.

ks

 

[haywire4130]

Strange... what does the map show on pl with key on engine off? Maybe rig up a regulator to shop air with a trusted gauge and apply air to the map sensor while watching pl and compare readings?

 

[KEVINS]

I've already compared the mech. gauge to the Xdcr and found that the mech gauge reads about 2psi higher than PL.
CNTRL B will zero out PL with key on, engine off.

Right now I feel I have an understanding of the boost pressure readings, now I need to verify voltage to the XP pump which is already hotwired. Either the voltage isn't where it should be or the pump is going on vacation after all these years.

ks

 

[KEVINS]

Update:
Reminder: I was running 30psi of boost but only getting 52psi of fuel pressure at this boost level.

I checked the hot wired XP pump and with key on engine off I had 12Volts to the electrical plug to the pump so I decided to install a new pump and do some good wiring to the connectors while I had it apart. I installed a DW300 and set base fuel pressure to 43psi then tested. At 26psi of boost the fuel pressure went to 65psi and it should have been 69psi. Injector duty cycle is 112 (42.5lbs - 009's) and O2's are at a very safe 800-820 with alchy.

One question I have is how many people are NOT getting a TRUE 1:1 with the boost:fuel pressure and are living with it just fine?

A second question is what harm is there in raising the base fuel pressure 3-4psi and leave it there?

A third is who makes a good fuel regulator that does give a 1:1? Mine is the old Armstrong version of a modified stock unit with the adjustable cap so it's possible its being pushed beyond it's capabilities.

I have 60lb inj and a new chip waiting to go in but I want to get the fueling figured out before installing them.
thnx all.
KS

 

[John Wilde]

Kevin,

Most people run the Accufab:
https://www.accufabracing.com/fuel/product/83-buick-gn-fuel-pressure-regulator-1986-1987

Most of the vendors carry them and I might have extra.

 

[KEVINS]

Kevin,

Most people run the Accufab:
https://www.accufabracing.com/fuel/product/83-buick-gn-fuel-pressure-regulator-1986-1987

Most of the vendors carry them and I might have extra.

Thanks John!

ks

 

[TurboBuRick]

....

 

[KEVINS]

Update:
9/1/13
Maybe someone else can benefit from my findings below so I'll discuss the things I tried.
Trying to run 33-35psi boost safely.

Back story:
Not sure where to start so I'll give a quick rundown of my fuel pressure issues and the steps I took to remedy it.

To start I had 52-53psi of fuel pressure at 30+psi boost and alchy with a hot wired XP pump and Reds adjustable regulator that I installed 18 years ago.. O2's were around 780-800 so it looked safe but Power Logger showed the injector DC was over maxed at 117.

First attempt to fix it:
Verify that regulator goes up 1psi per 1psi of boost on the bench.. Yes it does.
Verified that there were 11.9 volts at the alternator and 11.8V at the pump connector with key on engine off. Verified gas tank also has a good ground.
Chose to install new DW300 and did some rewiring to the hanger.
Set base fuel pressure to 43psi then tested. At 26psi of boost the fuel pressure rose to 65psi (up from 52) but it should have been 69psi. Injector duty cycle is 112 (42.5lbs - 009's) and O2's are at a very safe 800-820 with alchy. But not getting a 1:1 rise in fuel pressure.

Second try to fix it:
Fuel filter was difficult to blow through so replaced it with a AC Delco unit.
Installed new billet fuel regulator.Set fuel psi to 43 and went for a test run.
At 26psi of boost the fuel pressure went to 65psi. The above changes didn't help.

One more try:
Zip tied the few remaining hoses around fuel regulator and the one on the vacuum block that feeds the regulator in case they weren't sealing under boost.
At 27psi boost the fuel pressure rose to 68psi and injector duty cycle dropped to 95% and O2's range from 820-770. Close enough.... WHEW!

Summary: I think there were TWO issues that caused the low fuel pressure
1. XP Pump was weak.
2. The small vacuum hoses that feed the fuel regulator needed zip tied b/c some boost pressure was leaking past them.

I'm confident that the fuel pressure issue is now fixed. I plan to move forward and install the new 60lb injectors that have been sitting here for the last month along with the new chip for them.

Despite the love/hate with volt boosters I also plan on installing one asap then crank up the boost some more.

I hope the above helps.
KS