fuel pressure and air/fuel ratio Please HELP...:(
 

quick set up background.

walboro fuel pump
golden eagle fuel rail
Sx fuel pressure regulator
AEM wideband gauge

And here is my problem.

Moving the screw on the FPR clockwize will increase fuel pressure, therefore the air fuel ratio should go RICHER, and vice versa.

But in my case it does the absolute opposite. The fuel pressure goes up but the car runs LEANER.

The wideband is good, I checked that.
The FPR is good, no leaks in the diaphragm
Changed the fuel filter

Im so stumped that I don't know what else to do. :S :S :S

any imputs will be considered. thanks so much.

UPDATE 12/01/05 :

I also changed:

fuel injectors
fuel pressure regulator
fuel pump
blew air through the return line
changed the banjo line form the filter to the fuel rail, with a AN-6 line
checked voltage at the fuel pump, 11.7v with car been sitting for a week
checked pressure of the fuel pump, over 100 psi with no return

Again, doing the same thing. I just don't know. :S

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Need more fuel than the pump can supply or get there?


JP

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

it does not make sence. this is with the car at idle, the pump should pump way more than what the car needs.

with the car at idle, I disconect the vacume hose from the fpr and the pressure goes up, but the car runs leaner. I makes no sence.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

At idle, huh? Hmmm, your right it would have PLENTY. Or should. Anyway to check BEFORE the FPR. Try a stock FPR? I don't know. You said it's fine though. Hmmmm.... :-\


JP

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

yea im in the same boat :-\ :-\ :-\ :-\ :-\ >:( :S

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

sooo.... turn it the other way and it will go richer, no?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

^^^ no, cuz when I hook up the vacume hose it goes richer and when I go to WOT or boost it will go leaner.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

just a theory here but it makes sense.

you say at idle you pull off the vacuum hose and the pressure goes up and it reads leaner? No idea why if you turn the fuel pressure up it reads even leaner....but plug the manifold hole so the RPMS don't go up and adjust it that way.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

^^ I did. when I adjust the fuel pressure I put a bolt in the hose from the manifold so the rpm's stay at about 900 where I have it set.

im gona see if anyone in the area has the same fpr and see if I can try theirs, so I know if that is the problem or not.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

sounds like it's possibly the fpr, that's what was happening to me when i tried raising my fuel pressure with a known bad fpr, it would run leaner at idle with the fuel pressure raised.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

yea, im going towards that way. I just have find another one to try it.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Update........

I chaged my fpr with good oem fpr and its doing the same thing. So next thing that im gona check is the fuel pump. wish me luck.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

You may have an injector problem. I had all kinds of wierd problems with my afr's. My car would go lean whenever it felt like it. Even when I would raise the fuel pressure. It would go lean at idle and sometimes when just cruising. I was running venom 660 cc injectors at the time. My problems made no sense. And sometimes my afr would go very rich at times without adjusting anything. I switched to dsm 450's and all my a/f ratio problems went away. Good luck.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Ya the only problem is he's pushing 550whp and 10sec timeslips. 450cc DSMs won't cut it!!!

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

??? ::) I didn't say anything about him using dsm 450's. I guess you completely missed the point.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

im using 1000cc precision injectors.

btw, I checked the fuel pump and it put out plenty of fuel. I took it out of the tank and test it. No problem there, good pressure and volume.

next thing to check is the injectors. im gona see if I can borow some 1000cc rc injectors from a buddy of mine, and see if that fixes the problem.

wish me luck. im not letting this problem kick my ass, im gona find the problem. there's nothing elese im gona do to the car, untill I fix this problem.

btw, thank you guys for helping. :-* ;D

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

---- THAT STEFAN rc1000's are shitt (they lock open/closed all the time)y, my dad said you could borrow his 1000's if you want. hit me up.


-Josh

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Well I jsut put in a set of 1000 cc Rc injectors and same thing happens >:( I don't know what else to do. ???

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

How much fuel pressure are you running at idle?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

^^ im only running about 35psi fuel pressure at idle.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Can you grab another WB to check with? Perhaps your's has taken a ----.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

I thought my WB would be bad, but its not. If I increase the injector % in my ecu the air/fuel will get richer, and if I decrease the injector % the a/f will get leaner. So I know that works just fine.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

well I just got done replacing the injectors and its doing the same thing. I also checked voltage at the fuel pump and it has 11.5v with the ign on.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

put in a larger diameter fuel return line. not sure if it has anything to do with the problem, but when i added a larger capacity fuel pump i had to increase the size of my return line. the car was acting funny and surging and bogging related to fuel pressure i thought... when i put it in it seemed to help. i think at this point you're willing to try anything.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

i could be way off, but i remember reading somewhere that increasing fuel pressure is more to atomize the fuel better and not really to get more in, so if the fuel is getting broken up better then it will burn better then the WB would show it being leaner. also, if you are running 1000cc injectors then you have to be using some sort of computer control, why not just richen it up with your fuel map? again i could be way off, my car isnt boosted yet, but i am running 450cc injectors with uberdata.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

I did put in a AN-6 return line with braided hose. it made no difference. But yea, right about now im ready to try anything.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

I could just richen up the fuel map, but I feel like im covering something up thats not working right. So I want to make sure that it works right before I end up tuning the boost.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

maybe your lines are too small now??

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

stock lines should be more than enough at idle, don't you think.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

have you thought about trying out another car like joshes dad's to see it reacts the same to fuel pressure adjustments at idle? sounds stupid but maybe its just some sorta fluke?

Beau

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

No I have not, but I did double check everything twice in the mechanical fuel system. Im going to start looking into the electornic part more. Im gona check the rezistor box, ecu, voltage through out the sys.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

11.7 V sounds a little low... maybe check your pump wires and or grounds?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

the car was not running, just the ign. was on and the car had been sitting without running for about a week. So I think that was ok for voltage cosidering that the car had not been starterd in a week.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

updates?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

still ------- arownd with it. Its doing the same thing. I changed everything that I can think of. Including the Power Fc. Im going to try to tune it, and see how much fuel it takes under boost.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Did you ever get this working right?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

once I saw guy having his FPR attached where fuel gets int the rail, so when he was increasing fuel presure (squizing fuel hoze) actually he was restricting fuel geting into the rail, stupid thing, but here when you are "increasing fuel pressure" there is less fuel/fuel presure on injectors. Could post some pics? This will help I believe.

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

Bump. Any progress?

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

i would put money that he has it set up right...he does quality ----

Re: fuel pressure and air/fuel ratio Please HELP...:(
 

well, I think I fixed the problem, but I don't know what caused it. I changet a few things at the same time, and it works good now. Im putting in my surge tank soon with an external fuel pump, so ill update you guys really soon. I been really busy lately, and not too much time to spend on my car. ;)