8 minutes ago, Zed Head said:

Why would you not use EFI hose? If the leak is on the high pressure side, that might be the reason.

Right after I got my car and got it running again, but before I had given it a good examination, I was out for a short test/tune drive and a UPS driver pulled up beside me and flagged me down right after I had left my neighborhood. He said there was liquid pouring out from the under the back of my car. I pulled over to check it out and found that the hose from the fuel pump had split. It was not EFI hose. A PO had used the wrong hose and it had fatigued and come apart. That UPS guy probably saved my car. And this was after I had made a few high speed runs down the freeway. I got really lucky. There was a guy behind me who cared, I was on a two lane road where he could pull up beside me, and it had split at just the right time.

Fair point, I'll give it a shot.

As a side note, with the tank house outlet and the fuel pump inlet hoses being a different sizes, the PO had a metal cylindrical adapter that he popped into the tank hose side, put the fuel pump hose over it and clamped it down (this is of course on the low/no pressure side since it is just where fuel flows down into the pump from the tank). The car has always been setup like this and that joint has never smelled like fuel - but I was always curious if using an adapter like that is how all 280z folks overcome this issue.

See below picture for what I'm referring to - you obviously can't see the metal adapter since it is inside/covered by the hose. The ziptie is there to hold the fuel line up.

I think that most of us go to the hardware store and find the barb that fits the hose.

Looks like that hose rubs the halfshaft over the bumps. That whole setup looks a bit sketchy. Gasoline fires are scary. I've scared myself at times just lighting the BBQ coals in the backyard grill.

3/8 hose into the pump. 5/16 EFI hose out. You have the wrong fittings on the pump I believe

8 minutes ago, Zed Head said:

I think that most of us go to the hardware store and find the barb that fits the hose.

Looks like that hose rubs the halfshaft over the bumps. That whole setup looks a bit sketchy. Gasoline fires are scary. I've scared myself at times just lighting the BBQ coals in the backyard grill.

Do you have a link to that part (or the hose sizes) and I'll pick it up? The one I have is the same outlet size on both size which is why the larger hose slips over the tank one with the metal piece in the middle. Also besides the zip tie I added, how did these lines used to be held up?

Edited September 24Sep 24 by chaseincats

1 minute ago, Yarb said:

3/8 hose into the pump. 5/16 EFI hose out. You have the wrong fittings on the pump I believe

The wrong fittings meaning the clamps on each hose? This is the setup that I've had on there for a decade so it's odd its having this issue now that I changed to new hoses.

That barb image is from the link you gave for your pump.

I'm pretty sure that most aftermarket pump setups have some sort of cobbled together fixturing. I used some of the metal tubing from the original setup and some creative hose routing. I put a loop in the hose to make the sharp bend that is a typical problem back there, from the pump the damper.

It can be a difficult puzzle.

22 minutes ago, Zed Head said:

That barb image is from the link you gave for your pump.

I'm pretty sure that most aftermarket pump setups have some sort of cobbled together fixturing. I used some of the metal tubing from the original setup and some creative hose routing. I put a loop in the hose to make the sharp bend that is a typical problem back there, from the pump the damper.

It can be a difficult puzzle.

I remember the ideal way I saw was to loop the hose up and over one of the metal things under the car (working on this was so long ago i don't remember what 'metal thing' it was) but that ended up making the tank line angle like this: /-\ which hindered fuel flow.

Could you take a picture of how you have yours routed?

What about the FPR? Good hoses and clamped off tight? Can those be tested? I bought a new one from '78 to work with my diy fuel rail. Needed only one in and my '77 had 2.

10 minutes ago, siteunseen said:

What about the FPR? Good hoses and clamped off tight? Can those be tested? I bought a new one from '78 to work with my diy fuel rail. Needed only one in and my '77 had 2.

The FPR is good. I tested it by clamping off the return line (the hose that comes out of the lower outlet of the fuel rail) and let it sit overnight. The car had the hard start issue. I then instead clamped off the inlet hose (the one coming from the fuel pump) and the next morning the car started without issue. That is how I determined how to test which item is not holding fuel/fuel pressure when shut off.

Edited September 24Sep 24 by chaseincats

The FPR @siteunseen is speaking of is on the injector fuel rail itself.

13 minutes ago, Yarb said:

The FPR @siteunseen is speaking of is on the injector fuel rail itself.

Right, I was curious if the FPR was letting fuel bleed past and into the tank, so I clamped the line that comes after the FPR in the same way as I tested to see if the car was losing pressure after the fuel pump, so I clamped the line that heads into the fuel rail

Considering everything, I would remove the pump, get the proper hose barb for the inlet, take the banjo fitting off of the outlet and see if you can identify the check valve, and try to fix it. It might just be a piece of rust or debris in the check valve seat.

You need to fix that zip tie mount anyway. If that breaks, the hose ends up on the spinning halfshaft and you could easily end up spraying fuel and creating vapor back by the muffler. A fire/explosion waiting to happen.