@SteveJThanks for the link to the curved fuel hose. I wish I found it before I made a U-shaped 3/8" line out of the brake line.

@Zed Head My bad, I have had 2 Ultra-Power fuel pumps. They look identical to the previous owner's Airtex, even share the same 8312 part number.

Delphi shows the maximum pressure of 107 psi, I can't find the minimum one. The OEM part it referenced is E8312 (Amazon link: https://www.amazon.com/Delphi-FD0035-Electric-Motor-Solenoid/dp/B000CGFV2Y)

The Delphi's warranty PDF mentions that "This Limited Lifetime warranty lasts as long you own the vehicle in which the Delphi Electric Fuel Pump or Fuel Pump Assembly is installed. This warranty is not transferrable and applies only to the original purchaserof the product."

I guess I can give it a shot, although swapping fuel pumps even when they are offered for free, is still a messy time consuming job. Thanks for the pump refernce.

This just came to mind when you were talking about a “side winder hose”. Here’s a couple of pics of a line that came with my fuel line kit from SS Tube. Hooks to the factory pump configuration but might work on other applications. You can order it separately and possibly continue on with straight hose. Just a thought. Good luck with your project.

Doesn't show up on the web site.

https://www.sstubes.com/search?q=280z&_pos=3&_psq=280z&_ss=e&_v=1.0

 

Comes in a kit but you can call and order it separately. Good folks there, great customer support 

On 8/19/2023 at 9:52 PM, darom said:

Rockauto is going to give me a refund (minus FedEx s&h fee to send the faulty unit back to them), since this is the 2nd unit that failed on me within a year. I have put about 40 miles on the car since the installation.

That's the problem with RockAuto - if you have repeat failures of a component, they count it against your account standing, which affects how they treat you overall. I had this issue whenI had 2 pairs of one brand of shock fail within a year of each other. 

I ended up installing my new spare MSD-2225 fuel pump. If (or better, when) this one fails, I will go Dephi route with its lifetime warranty. Thanks to all for your insight.

Good evening,

My fuel pump saga never ends.

I replaced the failed MSD (lasted 2 years) one with a Walbro GSL392 255LPH (authentic, made in USA, sold by Summit) in August 2025. I am running Microsquirt, set the base pressure at 43 psi with Aeromotive FPR. All is good until today. I took the car for a test drive fine tuning my VE table, the car was bucking, popping noises through the exhaust. I noticed my fuel pressure was bouncing around 20 - 38 psi, then dipping into 10s. The pump started making squealing noises.

In the Tuner Studio, one can operate a test mode with the fuel pump. With the vacuum disconnected, my fuel pressure won't stay stable, would move between 30-40psi on my fuel pressure gauge.

There is a 75amp relay with a 20amp fuse which supplies power to the pump. I ran a positive direct wire via the relay from the battery to the pump, separate good ground. There is almost no voltage drop at the pump's electrical contacts.

The pump is in the lowest horizontal position, as close to the tank as possible, with no sharp kinks in its fuel line, 100micron fuel pre-filter. Half of tank of clean fuel. No debris in the fuel filter.

I am back to using my original fuel tank's lid which has a built-in pressure relieve valve. When unscrewed, I can hear some little air pressure being released.

I am not sure what else to do to make my fuel pump reliable. I found some posts about a 280z guy with weak fuel pressure issues using the same Walbro pump. He ended up installing a pusher pump then a puller pump. How did the Datsun's stock fuel pump manage to handle this all these years? Do I need to look into putting a sump tank with a puller pump (submerged inside) and then using my external Walbro as a pusher pump? Maybe installing the whole sump in the engine bay (RH side)? Any suggestions? The original Datsun design pumps go for over 1200 bucks (at Z Car Depot)! If I can find a cheaper reliable replacement/alternative, that will be a winner.

Any advice is appreciated,

Den

I'm not convinced it's the pump yet. Does it do it with the gas cap off?

Are you sure the tank is clean, no rust, no debris?

Can you rig up a temporary tank and see if the issue goes away? I have run into this in the past

Hi Charles,

Thanks. I tested it without the gas lid on. The pump was turned on in TunerStudio in test mode (engine is off, battery is 12.7V, pump - 12V). The in-cab fuel pressure gauge showed 30-37psi fluctuations accompanied with an annoying squealing noise. My FPR was set at 43psi (no vacuum attached).

Last week I drained gas 3 times getting my fuel sender's float adjusted (my fuel gauge is properly showing the value now, small victory :-)). The gas was clean. I used Fram (F3?) clear pre-filters (30 micron) for the past 12 years before I decided to move up to a 100 micron one chasing previous fuel pumps' failures.

I am just debating if I should start looking into a gas surge tank/dual pump setup? When the pump worked yesterday, the car felt like a rocket ship.

I helped a friend with his 280. fram filter was clean but fuel pressure was poor. I rigged up a 5 gallon jug in the hatch with feed and return lines. Ran great with that setup. There is a very fine mesh filter inside the swirlpot in a 280z tank. They can get stopped up, corrode or pull sediment up when running. None of this showed up in drained fuel. He split his tank and redid it.

I recommend you try setting up a temporary tank for testing purposes. But no smoking!

3 hours ago, darom said:

Aeromotive FPR

1 hour ago, darom said:

The in-cab fuel pressure gauge showed 30-37psi fluctuations accompanied with an annoying squealing noise. My FPR was set at 43psi (no vacuum attached).

Might be the regulator. They typically have very large seat area valves that can easily get jammed with a piece of debris. Are you sure the squealing is coming from the pump? The pressure must have been set before the test. Have you tried adjusting it while testing?

The simple test of pump power is to squeeze the return line while the pump is running. If pressure does not rise it's the pump. If pressure does rise it's the regulator. If you find it's the regulator you might as well take it apart and look. There's really not much to them.

Charles, this is a good point. I will insert my remote mechanic's camera through the filler neck or through the fuel sender's access to check the condition of that mesh filter/sock on the bottom. I hope I won't have to drop that tank. When I bought the car 15 years ago, I was lucky that the fuel tank inside was in a great condition without any rust. If this is indeed the mesh, would you suggest completely getting rid of it since we use pre-filters anyway?

Zed, the noise is definitely coming from the pump. Its noise varies depending on the output I am seeing on my fuel pressure gauge. I will do the test with restricting the return line and share the results. Before my test drive, I did adjust the FPR and couldn't get a stable 43 psi reading (no vacuum), it was moving between 40 and 43 psi. I left it alone without giving much thought to it. A year ago the FPR adjustment for 43 psi was steady, no pressure variations.

Thanks for your suggestions!