SR Fuel Pressure Problems - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

the head · 04-24-2008, 08:15 AM

Running a Sard regulator set to 43 with no vac all -6 line new fuel filter and rather new Walbro pump, 550cc injectors top feed.

As soon as the boost comes up out of vac the pressure drops to 20 but according to the wideband hooked into my haltech I am still running full rich (5V)

any help is appriciated

posdrift240 · 04-24-2008, 08:33 AM

What fuel pump are you running?

the head · 04-24-2008, 11:56 AM

walbro walboro 255 high pressure

los_inc · 04-24-2008, 12:06 PM

make sure all the rings on the fuel rail are in decent shape also make sure your rail is properly secured your not loosing fuel pressure from them
-los
goodluck

the head · 04-24-2008, 03:14 PM

yup no leaks under pressure

SoguRacing · 04-24-2008, 04:14 PM

ok, well typically on the stock fpr when the manifold is pressurized the fpr will increase fuel pressure about 1psi per pound of boost. as you can see with the stock fpr there is a vacuum line from the throttle body to the fpr. If there is a vacuum port you should have it connected. remember that static pressure and volume are two different elements.

bigOdom1 · 04-24-2008, 04:22 PM

make sure the wiring on the fuel pump is not backwards

clark · 04-24-2008, 04:25 PM

are you sure you have the correct fuel line going into your rail?
there is common confusion with the source line an the return line.

it sounds like your fpr is "stuck" and not reacting to boost.

give us the background on what the setup was before the new fpr and an fittings, fule pump, etc
did everything work ok before your upgrades?

04-24-2008, 08:15 AM	#1
the head Nissanaholic! Join Date: Jul 2002 Location: in a dark room mastering the art of typing with one hand Posts: 2,164 Trader Rating: (3) Feedback Score: 3 reviews	SR Fuel Pressure Problems Running a Sard regulator set to 43 with no vac all -6 line new fuel filter and rather new Walbro pump, 550cc injectors top feed. As soon as the boost comes up out of vac the pressure drops to 20 but according to the wideband hooked into my haltech I am still running full rich (5V) any help is appriciated __________________ I never knew you could do that with an eggplant

04-24-2008, 08:33 AM	#2
posdrift240 Zilvia Member Join Date: Oct 2007 Location: Rhea Posts: 207 Trader Rating: (0) Feedback Score: 0 reviews	What fuel pump are you running? __________________

04-24-2008, 11:56 AM	#3
the head Nissanaholic! Join Date: Jul 2002 Location: in a dark room mastering the art of typing with one hand Posts: 2,164 Trader Rating: (3) Feedback Score: 3 reviews	walbro walboro 255 high pressure __________________ I never knew you could do that with an eggplant

04-24-2008, 12:06 PM	#4
los_inc Zilvia Addict Join Date: Apr 2006 Location: New Joisey Bro. Age: 40 Posts: 826 Trader Rating: (15) Feedback Score: 15 reviews	make sure all the rings on the fuel rail are in decent shape also make sure your rail is properly secured your not loosing fuel pressure from them -los goodluck __________________

04-24-2008, 03:14 PM	#5
the head Nissanaholic! Join Date: Jul 2002 Location: in a dark room mastering the art of typing with one hand Posts: 2,164 Trader Rating: (3) Feedback Score: 3 reviews	yup no leaks under pressure __________________ I never knew you could do that with an eggplant

04-24-2008, 04:14 PM	#6
SoguRacing Post Whore! Join Date: Nov 2007 Location: (714) Age: 39 Posts: 2,967 Trader Rating: (23) Rides Gallery: SoguRacing Feedback Score: 23 reviews	ok, well typically on the stock fpr when the manifold is pressurized the fpr will increase fuel pressure about 1psi per pound of boost. as you can see with the stock fpr there is a vacuum line from the throttle body to the fpr. If there is a vacuum port you should have it connected. remember that static pressure and volume are two different elements. __________________ Pre Tune Checkup! Compression,LeakDown,Vacuum Test $80. Cams Install: $180

04-24-2008, 04:22 PM	#7
bigOdom1 Nissanaholic! Join Date: Nov 2005 Location: Auburn/Birmingham AL Age: 41 Posts: 1,817 Trader Rating: (4) Rides Gallery: bigOdom1 Feedback Score: 4 reviews	make sure the wiring on the fuel pump is not backwards __________________ my car domain that good review thread

04-24-2008, 04:25 PM	#8
clark Zilvia FREAK! Join Date: Mar 2008 Location: new york Posts: 1,035 Trader Rating: (1) Feedback Score: 1 reviews	are you sure you have the correct fuel line going into your rail? there is common confusion with the source line an the return line. it sounds like your fpr is "stuck" and not reacting to boost. give us the background on what the setup was before the new fpr and an fittings, fule pump, etc did everything work ok before your upgrades?