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

anthonythomas08 · 07-12-2008, 12:30 AM

I have recently replaced my old fuel pump for a new one (old walbro went out so I put in a new one). I think my car was running pretty rich so I went ahead and put in a FPR that is supposed to piggyback off of the stock FPR.
The Fuel Pressure Regulator is only setting my Fuel Pressure at 42psi. I need it to be at 36psi- per the fsm. I have a ca18det engine just to let you know.
Is this normal? I thought that I would be able to adjust my fuel pressure lower and higher, this is just allowing me to up the pressure.

Thanks for any help.

rc1honda · 08-29-2008, 12:13 PM

Im having the same problem right now in my SR. I just swapped the motor with my freind. BTW he did most of the work im still learning from scatch.
Well now when we start it we r seeing that the fuel pressure is like at 80psi with the walboro, And i think Nismo FPR, so then we put the stock FPR back on it still is pushing 80psi. I have no idea what to do nor to be honest have any real experience with engines. Take it easy on me and advice would be great. Maybe just putting the old fuel pump will work but i have 50lb iinjectors to.

the head · 08-29-2008, 12:46 PM

anthony,
are you running two FPRs? Please clairfy.

RC51
If it is that high something is blocking the flow back to the tank look for pinches or kinks in the fuel return line both rubber and metal hardlines under the car.

UNISA JECS · 08-29-2008, 01:19 PM

Quote:

Originally Posted by anthonythomas08

I have recently replaced my old fuel pump for a new one (old walbro went out so I put in a new one). I think my car was running pretty rich so I went ahead and put in a FPR that is supposed to piggyback off of the stock FPR.
The Fuel Pressure Regulator is only setting my Fuel Pressure at 42psi. I need it to be at 36psi- per the fsm. I have a ca18det engine just to let you know.
Is this normal? I thought that I would be able to adjust my fuel pressure lower and higher, this is just allowing me to up the pressure.

Thanks for any help.

Dont expect to lower your fuel pressure if your still running the stock FPR. Piggy backing the stock FPR will only let you raise fuel pressure NOT lower it.

rc1honda · 08-29-2008, 01:35 PM

Then how do you lower it?

japslapsilvia · 08-29-2008, 01:53 PM

get rid of the stock FPR and use a fully adjustable unit like sard aeromotive etc...

rc1honda · 09-01-2008, 02:03 AM

Good work The Head, i checked the fuel return and it was blocked, thx for the help, if i knew how to give rep out i would.

BiG MiKE86 · 09-01-2008, 08:17 AM

Quote:

Originally Posted by rc1honda

Good work The Head, i checked the fuel return and it was blocked, thx for the help, if i knew how to give rep out i would.

U see that little scale under the username - thats for rep.

07-12-2008, 12:30 AM	#1
anthonythomas08 Leaky Injector Join Date: Jan 2008 Location: San Diego Age: 35 Posts: 121 Trader Rating: (2) Feedback Score: 2 reviews	Fuel Pressure Problem!!! I have recently replaced my old fuel pump for a new one (old walbro went out so I put in a new one). I think my car was running pretty rich so I went ahead and put in a FPR that is supposed to piggyback off of the stock FPR. The Fuel Pressure Regulator is only setting my Fuel Pressure at 42psi. I need it to be at 36psi- per the fsm. I have a ca18det engine just to let you know. Is this normal? I thought that I would be able to adjust my fuel pressure lower and higher, this is just allowing me to up the pressure. Thanks for any help.

08-29-2008, 12:46 PM	#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	anthony, are you running two FPRs? Please clairfy. RC51 If it is that high something is blocking the flow back to the tank look for pinches or kinks in the fuel return line both rubber and metal hardlines under the car. __________________ I never knew you could do that with an eggplant

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08-29-2008, 12:13 PM	#2
rc1honda Zilvia Junkie Join Date: Aug 2008 Location: Chicago Age: 39 Posts: 432 Trader Rating: (5) Feedback Score: 5 reviews	Im having the same problem right now in my SR. I just swapped the motor with my freind. BTW he did most of the work im still learning from scatch. Well now when we start it we r seeing that the fuel pressure is like at 80psi with the walboro, And i think Nismo FPR, so then we put the stock FPR back on it still is pushing 80psi. I have no idea what to do nor to be honest have any real experience with engines. Take it easy on me and advice would be great. Maybe just putting the old fuel pump will work but i have 50lb iinjectors to.

08-29-2008, 01:35 PM	#5
rc1honda Zilvia Junkie Join Date: Aug 2008 Location: Chicago Age: 39 Posts: 432 Trader Rating: (5) Feedback Score: 5 reviews	Then how do you lower it?

08-29-2008, 01:53 PM	#6
japslapsilvia Zilvia FREAK! Join Date: Nov 2007 Location: dallas, TX Age: 38 Posts: 1,244 Trader Rating: (12) Feedback Score: 12 reviews	get rid of the stock FPR and use a fully adjustable unit like sard aeromotive etc...

09-01-2008, 02:03 AM	#7
rc1honda Zilvia Junkie Join Date: Aug 2008 Location: Chicago Age: 39 Posts: 432 Trader Rating: (5) Feedback Score: 5 reviews	Good work The Head, i checked the fuel return and it was blocked, thx for the help, if i knew how to give rep out i would.