I started tuning my 86 GN.To get the BLM's and 0/2 readings within specs for idle and WOT I had to MAX out the fuel pressure regulator.This puts my fuel pressure at 76 psi at idle! What is going on?
I have 32# disc injectors,High flow fuel pump,Kenne Bell Boost-A-Pump,TH 3" downpipe,3" freeflow CAT,70mm Accufab TB,and a Art Carr shift kit.
Any ideas? Thanks in advance,Curt.
Who's chip? I wouldn't worry about the blms to much. what's the 02 at WOT with 100PSI, can't be good. Check the usual VACCUM LEAKS and not just at the regulator. You checked the fuel filter I hope! Dont forget, any leaks after the MAF sensor will do all kinds of wierd s#@!
I have the same Problem, I installed a Walbro 307 fuel pump with a new fuel filter and also a billet alluminum adj, FP regulator. It worked great for about a week, then the pump disconnected from the pulsator in the tank and i had no pressure, so I removed the pump again and removed the pulsator and installed a fuel line hose directly, now my car is steady at 80psi at idle with vacuum off the FPRegulator. I have checked the return line and it is fine. What possible vacuum leaks can I have that can cause this. Thanks for any info. I have a 87 GN
You can't back the pressure down with the regulator? When you put the vaccum line back on, how far does the pressure go down? It might be stuck closed, you said it was brand new? I'd take the regulator off and make sure it works right.
thank you for your feedback, however this is the second one I have installed on it, what are the chances of having two bad billet adj fuel regulators. The needle does not drop at all when I connect or disconnect the vacuum line. It just stays steady at 80psi However when I turn off the car and only have the key in the on positon I can adjust the screw on the FPR and I can see the needle going up and down on the guuage so it is adjusting, but once the car turns on away it goes to 80psi turn the screw and play with the vacumm line and no go. It just stays steady at 80psi I am puzzled. I have donw all the tests and still cant figure it out. I have also changed the fule pump again with a brand new Walbro 307 and still the same. Any idead what the hell is going on here. LOL I am ready to pull my hair out. Thanks.
Like I said it worked great for about a week, I was just thikin can it be a voltage or wiring issue that is causing this kind of behavoir. Maybe where the connector are for the fuel pump from the gas tank. Can that be causin and unmormalites.
Hmm..maybe a clogged or misrouted return line? Did you pinch any hoses back at the pump when you put them back on? Rock-steady 80PSI just isn't normal. You're turning the adjustment screw counter-clockwise right? ;) (just making sure)
I'd follow the path of your gas from the tank to the fuel rail, then back again to the tank. Something's not doing it's job right in that fuel path - maybe you can spot it.
just my 2¢
Good Luck!
Jay
I ahve checked the return fuel line and it does shoot out fuel, it seems like there is no resitrictions on that part. i tuned it counter clock wise all the way through however with the car off and iginition on the needle can be ajusted but when the car turns on its steady 80 psi I have tripple checked for any pinced hoses and there are none. Its actually a three metal tubes coming out with three 4 inch fuel line pieces. I am puzzled, is there any sensors or vacuums that have an affect on fuel pressure maybe a relay, I dont know. Thanks for your reply.
The return line doesn't shoot fuel! take the regulator off and blow into the return line with an air hose(low press)Something isn't letting the fuel out of the rail, blocked return,or bad reg. Two bad regulators, I've heard stranger things! Where they from the same manufacturer? The pump runs full on all the time. With just the key on the pump stops after 2-3 sec.that's why you are able to adj.the pump isn't on.
What type of Fuel pressure gauge are you using? If it's electric could there be an electrical feedback that is causing the gauge to give a false high reading
it is a mechanical fuel guage and i have already replaced it with a new one thikini the old on was bad but still the same reading 80 psi with vacumm off at idle.
The return line shouldn't shoot the gas out, afterall it's just a return line. You mentioned the lines from the tank and it sounds like you didn't look at all of them. You should have the three metal tubes on the gas tank sending unit, then small rubber pieces that go onto three more metal tubes that are about a foot and a half long. Then you have more rubber hose pieces, then you have the main lines that run the length of the car. I'd follow them all the way. Good luck
the return hose is fine it is just spewing out the ritht amount its not shooting it like wild bill but its not drippin either. I dont understand what else it could be. ANy other ideas.
Thanks.
blocked or clogged vacuum line? It seems it must be mechanical at the regulator.....?
I have my car at the Mechanic's shop already getting some additional work done, Rear main seal, intake spacer, walbro 340, billet alluminum adjustable fuel reg, 3" down pipe, Duttweiler wide intercooler neck, adjustable waste gate acutuator, and 4 pro comp ultra lite guages along with a 5 inch 8000 RPM Tach. Cant Wait, I have no dam patience, LOL.
I will report back when I have the car which should be Wednesday.
I thank everyone for there help and there advise.
I just hope the mechanic is familiar with our cars. Preferrably one who only or mainly deals with them. Do you mean a Power Plate or just some spacer?
The Plenum Spacer for the intake I bought it from Poston, My Mechanic has a GN that is around 1000 hp 8 sec car I beleive.