Following up to my own question to help anyone in the future. Here's some good discussion on FPRs that are the same spec, but don't hurt the wallet as much...

I'd bet that they're all made in Asia now. One of these under $30 280ZX units might be worth a gamble. Probably all come from the same place. Not sure of the mounting, might have to cobble something up, but the pressure specs are the same.

https://www.ebay.com/itm/395767712629?_skw=280z+fuel+pressure+regulator

Yes, I saw those and was tempted. But felt like the idle PSI it claims was a bit too high, right? Shouldn’t it be more like 20PSI at idle?

Been a while since I had stone stock anything in my garage, but I seem to recall 40psi as the constant pressure. The older injectors dribble fuel if I recall correctly if the pressure isn’t high enough.

I think it’s great that you’re getting one back on the road!

My 78 model with factory efi ran right at 33lbs at idle.

It's been noticed in the past that many of the aftermarket FPR's seem(ed) to be set at 38 psi. Who knows why.

A $20 38 psi FPR would be better than a leaking FPR, probably. Also, any used original FPR probably has a stiff crack-prone diaphragm inside. And, if you get tempted to buy an adjustable aluminum FPR, be aware that they all seem to leakdown as soon as the pump shuts off. It's a trilemma.

Well, out of principle I refused to pay the $130 they want for a 78 FPR😅. So, I opted for the zcardepot $70 FPR that's technically for the 75-77 models. Still expensive for what is it, but I digress! I'll just plan on capping off the second fuel inlet. For those who may not know, 78 FPRs only have 1x inlet and 1x outlet, while the 75-77 FPRs have 2x inlets and 1x outlet. Internally, they function the same though.

Zed, I agree, any "used but functional" FPR is going to have a 50 year old diaphragm inside that could be hanging on by a hair, so I opted to go the "new" route.

I'll report back with the results, along with some fuel pressure readings.

2 hours ago, kcpope said:

Well, out of principle I refused to pay the $130 they want for a 78 FPR😅.

I'll look for a bolt in my drawer for an hour before I run out to the parts store.😁

Project cars have different meanings to people.

33 minutes ago, siteunseen said:

I'll look for a bolt in my drawer for an hour before I run out to the parts store.😁

Project cars have different meanings to people.

Half of the enjoyment I get in this process is using bits and pieces that I already have, researching youtube and forums for hours to figure something out, and never paying "the pros" unless I've exhausted all other options. I dunno what that is, but it sure scratches some itch in me. 😅

Edited October 20Oct 20 by kcpope

Looking for input…

It’s running and idling OK, but I want to get some input on the following gremlins:

• Replaced the FPR. Getting 34PSI at idle. Still seems a bit high to me. Might be related to my 2nd bulletpoint. Can anyone chime in with their reading at idle?

• I’m getting 16 inHg of manifold vacuum at idle. This seems low. Anyone want to chime in with their engine’s vacuum at idle? Mine is steady, no surging. Sprayed brake cleaner to check for vacuum leaks. Nothing. I’ll start by checking the EGR.

• Set timing at 10 deg. BTDC and idle at 800 RPM, just fyi.

Thanks for any suggestions. First check will be the EGR…

On 10/20/2026 at 11:05 PM, siteunseen said:

I'll look for a bolt in my drawer for an hour before I run out to the parts store.😁

In summertime with me it's the opposite, it means i have to drive my ZX to the store and have a nice drive (got myself a good excuse to drive the car!)

And sometimes IF i find the correct part or whatever I CAN DRIVE AGAIN! 😂

7 hours ago, kcpope said:

Looking for input…

It’s running and idling OK, but I want to get some input on the following gremlins:

• Replaced the FPR. Getting 34PSI at idle. Still seems a bit high to me. Might be related to my 2nd bulletpoint. Can anyone chime in with their reading at idle?

• I’m getting 16 inHg of manifold vacuum at idle. This seems low. Anyone want to chime in with their engine’s vacuum at idle? Mine is steady, no surging. Sprayed brake cleaner to check for vacuum leaks. Nothing. I’ll start by checking the EGR.

• Set timing at 10 deg. BTDC and idle at 800 RPM, just fyi.

Thanks for any suggestions. First check will be the EGR…

Here’s your input. You said it’s “running and idling OK” Just drive it. The rest will sort itself out.