Thread: Fuel Pressure Prime Question

Another update. So I tightened the BOV all the way, no change. I unplugged each injector and it seemed to effect it tho i could keep one unplugged to long cuz the idle was rough already and i didnt want it to die. HOWEVER, i started it back up with the MAF unplugged and noticed the idle was smoother and my vac was up around -18 i believe. My AFR however was rich at about 11.1-11.2...........is my MAF bad or perhaps the tune when fucko?

BTW: Never Tee the VAC line that runs to your FPR - Can't believe I didn't see this earlier.

i already called it, had him change that!

im sure the AFR went rich because thats what happens when u unplug the maf, it goes into a sort of limp mode an dumps fuel.. the idle bein better is cause it was richer, the vac, well as i've already said in irc might be low because of it bein so lean its nearly stalling..

Actually it's only getting up to 36 PSI according to your gauge.

3 BAR = 43.511 PSI at 0 FT Above Sea Level

iirc in a different video of it running it sat around 38 or so with the hose on an over 40 with it off.

he put one of the ones you sent him on, still same issue tho

That was a quick prime, but refer to the video in this post, while the car was running and when I pulled the vac line off its up by 43...not sure why the prime was that low, maybe it has something to do with pressure being leaked out. Not sure if the FPR is bad, but right now i have stock in and not in line gauge to know what the pressure is.
http://www.sr20-forum.com/general-sr20/68454-fuel-pressure-prime-question.html#post917178


Yeah the original owner T-ed that line and I gave them their own lines now.

So that doesnt mean anything as far as unplugging the MAF kinda of "fixing" the idle?

OEM dets are a 3 bar setup around 43.5 psi. Have you tried unhooking the fuel line beyond the fpr to verify a fair amount of fuel is coming out from it? Take a 20 oz bottle and hook it to the hose and switch the engine on but do not turn it over for 1 - 2 seconds and turn it off. Hook the line back up if you get fuel. Now try it on the inlet side to the FPR and see if you get about the same amount of fuel. If you do not I would suggest a new FPR. If you suspect injector issues I would unplug the injector clips one at a time and see if the idle dips. If it does the cylinder is normal. If it doesn't I would check for spark. If that is good then I would troubleshoot the injector.

My next suspicion is that you need to verify all parameters of the tune such as injectors, maf, and fuel pressure.

Sorry for not keeping up on you thread - but this one made me




You need to find someone that has a real smoke tester. I use a Smoke Pro from Redline Detection. Redline Detection Official Site – Smoke Pro Diagnostic Leak Detector — Smoke Pro® Total Tech®

Glad you saw that - can't believe I missed that.

VAC is affected by RPM.


I ASSume that the breather hose by the Brake Master is going to the trans ???


He really needs a data reader aka Techtom to see what his IACV is doing too.

@LAM, yeah I wish i had one of those smokers, bishes are to expensive and a black&mild was a buck lol! That breather is actually from the PS line i think. The guy left the PS pump off and everything and that breather goes down to something in the firewall. I got a picture if you'd like to check it out. Lynch saw it though, think thats what he said he thought it was coming from. I have one of those Nissan Consult cables and theres a USB coming from the Calum RT Ecu......


@Luke, I tried unplugging the injector thing, i had to do it quick because of the low idle and i didnt want the engine to completely die but it seemed like all injectors being unplugged effected it. I didnt varify the fuel coming out like you suggested but to eliminate the FPR being an issue i put the stock on back on. I have a new set of NGK plug wires coming in as we speak that im going to put on becuz regardless i think he needs them. I dont know anything about tuning so i'd need someone to perhaps remote connect to my computer and check it out for me.