what causes change in fuel pressure?

[Superwho05]

in a new swap, JDM b16, what would cause a rise in fuel pressure? its been like this ever since I put the motor in, its stock minus a skunk2 intake manifold off of one of my old ls-vtecs. Ive never encountered this before, so Im not sure if Im over looking something. is there a way to fix this without getting aftermarket fuel management?

 

[LS_VTEC]

What is the fuel pressure at?

 

[Superwho05]

I think he said it was about 60psi, my friend tested it since I didnt have a gauge

 

[LS_VTEC]

60psi at idle?

 

[Superwho05]

yeah, he tested it at idle. it shouldnt be a vacuum leak, mostly new hoses, Im pretty stumped on this one

 

[LS_VTEC]

Is there an adjustable FPR on the rail? (fuel pressure regulator)

 

[Superwho05]

nope, all stock but the intake manifold

 

[LS_VTEC]

Could be a bad FPR. Try replacing it with an adjustable one and try to bring the fuel pressure down.

 

[Superwho05]

I was thinking about it, I was just trying to see if anyones came across this, appreciate the help

 

[LS_VTEC]

Adjustable FPR's arent exactly expensive. Just pick one up along with a FP gauge, and mount it in-line with the fuel filter. Then adjust the regulator to 30psi at idle.

 

[99sidude]

Adjustable FPR's arent exactly expensive. Just pick one up along with a FP gauge, and mount it in-line with the fuel filter. Then adjust the regulator to 30psi at idle.

30 psi? That seems a little low to me. I just set mine today, the fsm called for 39-44 psi at idle for a b18c1.

If the regulator doesn't fix it, your problem could be a kink in the return hard line. I had that happen when I first got my car.

 

[svaby]

ah ya good post, my car is running rich as hell and i think my fuel pressure is way high on it, Whats the specs on a D16z at idle ?

Thanks in advanced.

 

[YBLEGAL]

lol your improper spelling got you closer to the answer than I will.

go to Advanced Autoparts, or autozone or w/e, and get a Chilton or Haynes manual for your motor's car (if it was swapped). you should have one of those on hand anyway.

invaluable resource

and, do us a favor and try not to thread jack

 

[LS_VTEC]

30 psi? That seems a little low to me. I just set mine today, the fsm called for 39-44 psi at idle for a b18c1.

If the regulator doesn't fix it, your problem could be a kink in the return hard line. I had that happen when I first got my car.

Half asleep when answering that post. 40psi is the correct fuel pressure at idle. DURRR.

Also, a kink in the return line wouldnt decrease fuel pressure going into the rail, it would actually hold more pressure in the rail. Fuel lines are pretty hard to get kinks in, its either bent/restricted or its not.

 

[Taco15]

looks like you have a leak somewhere man. Check your lines again. Do you have an aftermarket Fuel pump?

whats the idle set at?

 

[newb]

Also, a kink in the return line wouldnt decrease fuel pressure going into the rail, it would actually hold more pressure in the rail. Fuel lines are pretty hard to get kinks in, its either bent/restricted or its not.

Didnt the OP say it tested at 60 PSI? If his return line was kinked wouldnt that cause a higher reading at the inlet of the fuel rail?

 

[BrutalB83]

ah ya good post, my car is running rich as hell and i think my fuel pressure is way high on it, Whats the specs on a D16z at idle ?

Thanks in advanced.

Go buy a manual for your car. If you still don't understand, then start your own thread and maybe someone will help you...

 

[Superwho05]

wow, got busy on here while I was gone lol. I have a manual, didnt see a kink anywhere in the return when I had it on a lift a few weeks ago doing the exhaust, and Im not leaking anywhere. all the vaccum lines are new and ran correctly, and all signs are pretty much now pointing to a faulty fpr.getting a new one in a few days, so Ill let ya know how it goes. really appreciate the help, and brutal.... " 'maybe' someone will help you..." *sigh* priceless

 

[Superwho05]

btw taco, stock fuel pump, and idles at 700, smooth suprisingly, its when Im driving where the problem shows itself by excessive backfire, and (as retarded as it sounds) it sounds like it starts to purr if I hold the throttle/gas pedal steady when cruising.