Best replacement fuel pump option - Infamous Nissan

Honeyhardbody · 01-22-2022, 09:02 PM

Got a CEL for running lean.

It's probably time for a fuel pump replacement, I don't know when the current one has been replaced last but, its probably a safe assumption that it has been a while.

Anyways, there is a plethora of options out there for fuel pumps, I know most of them are just universal, BUT I'd like to get a reliable one with the easiest, closest to OEM install there can be.

Any suggestions?

SBJ · 01-22-2022, 09:12 PM

I'd be hesitant to condemn the fuel pump in this case. These systems are old enough that the fuel pump is either on or off, there's no duty cycle for it or anything like that. The pressure is actually controlled by the fuel pressure regulator on the fuel rail. If you have access to one, I'd use a scan tool that can monitor your fuel trims. If you are running lean your fuel trims will be noticeably high (0 is the magic number you're after).

It's easy enough to test the regulator, with no vacuum applied the valve inside the regulator should be closed you should have ~45 PSI. With a vacuum applied to it you should have somewhere in the neighborhood of ~35PSI. If your fuel pump turns on normally and the numbers check out good the fuel pump probably isn't the problem. I'd probably start by checking for vacuum leaks.

Honeyhardbody · 01-23-2022, 04:48 AM

Well this might sound kind of stupid but the truck never has had an intake hose. as long as I've known and its been a couple of years and plenty of road time.
Do you think that it would take that long to throw a code? Or do you think it could be my actually airbox or MAF?

SBJ · 01-23-2022, 05:10 AM

I think it probably would have thrown a code a lot earlier but it never hurts to check. The MAF is still downstream from the air filter, so it should still be fine. If you do need to clean it use mass airflow sensor cleaner instead of brake or carb cleaner. It will also run a little funny if the air filter housing is not seated all the way down on the throttle body.

Foul_Mouth · 01-27-2022, 05:07 PM

Walbro 255.

89'HBV6 · 01-27-2022, 05:19 PM

Quote:

Originally Posted by Honeyhardbody

Got a CEL for running lean.

<snip>

Any suggestions?

Fuel filter... clogged injector... so much more in the fuel system than just the pump.

What (specifically) was the error code? I suspect you have an OBDII reader?

Honeyhardbody · 02-18-2022, 10:55 PM

It actually might have just been the way the airbox was seated. I noticed one of the washers I had under the wingnut was freely spinning, added more washers, no more codes! Woooooooo

01-22-2022, 09:02 PM	#1
Honeyhardbody Join Date: Sep 2021 Location: Florida Posts: 13 Vehicle: 1996 Nissan D21 Pickup Thanks: 7 Thanked 1 Time in 1 Post	Best replacement fuel pump option Got a CEL for running lean. It's probably time for a fuel pump replacement, I don't know when the current one has been replaced last but, its probably a safe assumption that it has been a while. Anyways, there is a plethora of options out there for fuel pumps, I know most of them are just universal, BUT I'd like to get a reliable one with the easiest, closest to OEM install there can be. Any suggestions?

01-22-2022, 09:12 PM	#2
SBJ Total Buzzkill Join Date: Nov 2016 Location: OR Posts: 3,108 Vehicle: '90 D21 4cyl 5spd 2wd Thanks: 347 Thanked 593 Times in 527 Posts	I'd be hesitant to condemn the fuel pump in this case. These systems are old enough that the fuel pump is either on or off, there's no duty cycle for it or anything like that. The pressure is actually controlled by the fuel pressure regulator on the fuel rail. If you have access to one, I'd use a scan tool that can monitor your fuel trims. If you are running lean your fuel trims will be noticeably high (0 is the magic number you're after). It's easy enough to test the regulator, with no vacuum applied the valve inside the regulator should be closed you should have ~45 PSI. With a vacuum applied to it you should have somewhere in the neighborhood of ~35PSI. If your fuel pump turns on normally and the numbers check out good the fuel pump probably isn't the problem. I'd probably start by checking for vacuum leaks. __________________ FS5W71C transmission teardown and overhaul threads: http://www.infamousnissan.com/forum/...t=38961&page=2 http://www.infamousnissan.com/forum/...ad.php?t=39233

01-23-2022, 05:10 AM	#4
SBJ Total Buzzkill Join Date: Nov 2016 Location: OR Posts: 3,108 Vehicle: '90 D21 4cyl 5spd 2wd Thanks: 347 Thanked 593 Times in 527 Posts	I think it probably would have thrown a code a lot earlier but it never hurts to check. The MAF is still downstream from the air filter, so it should still be fine. If you do need to clean it use mass airflow sensor cleaner instead of brake or carb cleaner. It will also run a little funny if the air filter housing is not seated all the way down on the throttle body. __________________ FS5W71C transmission teardown and overhaul threads: http://www.infamousnissan.com/forum/...t=38961&page=2 http://www.infamousnissan.com/forum/...ad.php?t=39233

01-27-2022, 05:07 PM	#5
Foul_Mouth Pounding Rox Truck Join Date: Mar 2010 Location: Western NY Posts: 4,842 Vehicle: Too Many to List Here Thanks: 592 Thanked 879 Times in 685 Posts	Walbro 255. __________________ 1992 Supercharged and Body Swapped WD21 Pathfinder 1995 D21 Regular Cab 2wd (2)1991 D21 Regular Cab 1990 WD21 Pathfinder Frame 2004 Xterra 2010 Infiniti G37x Nissan Truck Videos (Builds-Racing-Shows-Tech) https://www.youtube.com/c/NissanTruckguy IG@ rainmaker_d21

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01-23-2022, 04:48 AM	#3
Honeyhardbody Join Date: Sep 2021 Location: Florida Posts: 13 Vehicle: 1996 Nissan D21 Pickup Thanks: 7 Thanked 1 Time in 1 Post	Well this might sound kind of stupid but the truck never has had an intake hose. as long as I've known and its been a couple of years and plenty of road time. Do you think that it would take that long to throw a code? Or do you think it could be my actually airbox or MAF?

02-18-2022, 10:55 PM	#7
Honeyhardbody Join Date: Sep 2021 Location: Florida Posts: 13 Vehicle: 1996 Nissan D21 Pickup Thanks: 7 Thanked 1 Time in 1 Post	It actually might have just been the way the airbox was seated. I noticed one of the washers I had under the wingnut was freely spinning, added more washers, no more codes! Woooooooo