So.... the problem wasn't really anything wrong at all

[NAM VET]

For the past several months, I have been vexed and flummoxed by a low fuel pressure. I put on another Facet 3-5 psi 24 V pump, another $220 Aeromotive fuel pressure regulator, re-did my rubber lines, moved filters to before and after the pump, checked voltages, connections, and yet, at start my fuel pressure on the dampened gage would read about 3 psi, and then drop to not much more than zero psi. the truck seem to run fine.

All this before and subsequent to setting the correct carb fuel pressure regulator. Called Pegasus Racing, where I get my fuel pumps, and also spoke with a well respected vendor, and their suggestion was a tiny air leak before the pump. So, again, checked those fittings, and again, re-did the rubber fuel liens, (all my hard lines are new CuNi lines" ).

Tried new filters, and just was so frustrating that my fuel pressure would drift down in about 15 minutes to about zero. I adjusted the regulator to give as much pressure as it could

Another call to Pegasus, and the tech guy suggested "burping" the dampened gage. So I slightly raised the rubber calibration seal, and instantly the pressure rose about 3-4 psi! So after countless hours, and perhaps near $400 dollars, there never was a problem. I wondered why it ran with almost no fuel pressure, but ir was fine all along.

Anyway, what a relief, so now I have a nice steady 4+ psi. Just a learning experience. hal

[refit1701]

Things like that will make you say bad words. I think there two sayings for this situation, so choose one if you wish:

1. When you have eliminated the likely, look at the unlikely.
or
2. It's always something obvious and stupid creating the problem.

It's great to finally find the solution.

[Cal_Gary]

Wow-I never would have considered (or have known) such a thing existed, Hal. Well Done!
Gary

[NAM VET]

Trying to think this problem thru, I wondered why my truck ran fine up hills with little or no fuel pressure. And the likelihood that two highly thought of Facet pumps failing was highly improbable. And my dampened fuel pressure gage has a tiny pin in a small rubber cap, and I thought that just pressing that tiny pin would "burp" the gage. But it was only when I lifted the edge of the small rubber gasket that the pressure immediately equalized. Took the whole small thing off, and the smaller-than-one mm pin was actually what put a little pressure on the rubber seal to keep it tight and waterproof. I didn't understand how to correctly equalize the air pressures. I was very reluctant to pull out the in-tank fuel pickup to see it it had a leak.

Many years ago, my brother-in-law was welding on a supposedly empty and dry gas tank, and it exploded and he spent six months in a burn unit and to this day has the scars from that. And also many years ago, I had a gas leak on a TR8, and the garage hot water heater pilot light ignited the leak and it blew up my Sports car and my garage. And I wondered how I was going to keep gasket debris from falling into the tank.

When I got my truck about 5 years ago, it was weathered a bit, but had virtually no rust, and just needed a full, home built restoration. Living in SC, I was able to do almost all of this out in my driveway, and taking most of our garage space for what I needed got do indoors. I spent a lot more $ than I had anticipated. It took a year of near full time effort. It was rewarding, but now, I just want to drive it, use it, and enjoy it. I am done with this restoration. Not long ago since my truck always ran at 200 degrees, I took out the military thermostat, and sure enough it didn't open until that temp, despite being marked as a 180 T' stat. Here in SC, on long trips, I just want my engine to run a little cooler.

I can't begin to express how I feel now that all is well, and my M37 starts and runs so well. I was so happy, I treated myself to buying a Ruger 44 mag carbine, something I have wanted for many years. Now, off to the range. .

Thanks to all, hal