Drag fuel pressure

[Wild Bill]

I put a auto meter pressure gauge on my fuel system so i can monitor it. When I tried it out it started at 62 # and after i ran awhile it stayed at 70#, I thought the regulator was a 56# unit. Next trip I will take a manual gauge and verify the reading at the sandbar. Do you think I should get another mercury regulator or adapt an aeromotive adjustable regulator to it?

[Stoker boy]

Is your return line flowing fuel back to the tank? Is the fuel tank vented?

[laser_ED]

I put a auto meter pressure gauge on my fuel system so i can monitor it. When I tried it out it started at 62 # and after i ran awhile it stayed at 70#, I thought the regulator was a 56# unit. Next trip I will take a manual gauge and verify the reading at the sandbar. Do you think I should get another mercury regulator or adapt an aeromotive adjustable regulator to it?

OK,we need a little more info on your fuel setup???What fuel pump,,,mercury black reg??Do you have the factory T valve[it lets the pressure off the injectors when pump is turned off] ..3/8 fuel line in 5/16 return,,,Where did you put the pressure gauge??Black reg 56lb gold reg 39lb .All I use is aeromotive bypass adjustable ..If you could post a picture it would help....Ed

[Wild Bill]

The system is all factory, black reg , T valve is their. Pressure bleeds off when pump stops. 3/8 fuel line, Weldon pump, 5/16 return, tank vented. Going to check the 5/16 line and the vent before i go out again. Line goes from Weldon pump to mercury water separating fuel filter to injector fuel rail. Installed pressure sending unit in spare port on the water separating fuel filter. Boat is an XR 2002.
I got more troubleshooting to do next time out, going to put a manual gauge on the schrader valve to verity pressure. This is the first time I ran it with a pressure gauge, could of had this problem a long time and not known about it. Might explain it being lazy right at the hit. But I run a 29 Hoss most of the time, that doesn't help. Don't run it real hard, barely have to crack that svs to be well over 100 right now. Rather be fat dumb and happy than lean and mean. Put an aeromotive reg on my 300x that works fine. Thanks

[Wild Bill]

Laser ED
If it is the regulator I think I will adapt a aeromotive reg like my 300x. That little black can merc calls a regulator looks cheesy, and i bet it is as expensive as an aeromotive.

[laser_ED]

The black regulator does not fail very often,i have seen maybe 2 In twenty yrs fail.The best thing on the aeromotive reg is you can mount a aeromotive pressure gauge on one of the unused ports.If its the Weldon pump that came with the drag engine it will be a 2015,they are supposed to have a bypass built into them.If your fuel pressure is that high then you are running very rich on your fuel tables.That would make it lazy.Which SVS ,,,gold with T valve or blue no t valve?What setting is your ECU at??

[Stoker boy]

[Stoker boy]

The little Tee on the fuel rail caused my fuel pressure to keep climbing I plugged it off, problem solved. At the time I was running a Weldon fuel pump and a aeromotive regulator. When I ran a Bosch pump and the black mercury 56 lbs regulator with the Tee I never had a problem.

[Wild Bill]

Blue svs, I think 101% is what Jay Smith set it at when he freshened it up.

[laser_ED]

The little Tee on the fuel rail caused my fuel pressure to keep climbing I plugged it off, problem solved. At the time I was running a Weldon fuel pump and a aeromotive regulator. When I ran a Bosch pump and the black mercury 56 lbs regulator with the Tee I never had a he.

The little T on the return line and fuel rail has nothing to do with fuel pressure,Mercury early on in the EFI program designed the T to address injector failure ,and that was with 39lb on the 2.4 240 Bridgeport,the 260 was also 39lb,with the A48 ecu.The first 56lb regs [black]came on the original 300 drag horn motor with the A63..The regulator in your post looks like the one brendon powers uses on his laser VST delete kit ,and he does not use a T......Ron Anderson was on the design team for the V6 program,and Jim Purcell merc engineer at plant 7 St Cloud use the T on all their EFI builds..All the newer EFI motors have the pressure relief built into the VST system...Sorry got carried away....Ed

[laser_ED]

Blue svs, I think 101% is what Jay Smith set it at when he freshened it up.

...Perfect at 56lbs,at 60lbs about 106 ,at 70lbs ??????????

[Stoker boy]

The little T on the return line and fuel rail has nothing to do with fuel pressure,Mercury early on in the EFI program designed the T to address injector failure ,and that was with 39lb on the 2.4 240 Bridgeport,the 260 was also 39lb,with the A48 ecu.The first 56lb regs [black]came on the original 300 drag horn motor with the A63..The regulator in your post looks like the one brendon powers uses on his laser VST delete kit ,and he does not use a T......Ron Anderson was on the design team for the V6 program,and Jim Purcell merc engineer at plant 7 St Cloud use the T on all their EFI builds..All the newer EFI motors have the pressure relief built into the VST system...Sorry got carried away....Ed

From what I understand it was designed to bleed off the pressure from the injectors once the engine is shut off. I don’t run a Mercury box. At this point the only thing I have from Powers is a fly wheel.

I think I bought the regulator from Summit racing. I do notice when I shut the engine off pressure is held for about for five minutes. So far it hasn’t damaged anything? I do have the bleed off plugged at this point. I’m currently running a Bosch pump and the aeromotive regulator it seems to be working fine.

[CI STV]

As stated above, fuel pressure should be set at 56 p.s.i. static. I set it with the engine off, since idle vacuum will pull the pressure down a few psi at idle, which is what the little vacuum hose on top of the regulator is for.
It’s weird that your fuel pressure creeps up like that. Before you toss the regulator, the first thing I would check is to make sure that your return isn’t kinked or pinched or plugged up with dirt, as that would cause pressure to rise. You need an unrestricted 5/16 or 3/8 hose, with the appropriated sized and unrestrictive fittings, all the way back to the tank.
If that’s not the problem, then would switch out to the regulator to the PPE, which comes with all the fittings, or an Aeromotive which is a little cheaper (~$175) but then you have to buy fittings, which adds up to about the same or more.
Here’s the PPE:
https://www.powerperformanceengineer...tive-regulator

This is the Aeromotive that I’m using:
https://www.summitracing.com/parts/aei-13136

[laser_ED]

As stated above, fuel pressure should be set at 56 p.s.i. static. I set it with the engine off, since idle vacuum will pull the pressure down a few psi at idle, which is what the little vacuum hose on top of the regulator is for.
It’s weird that your fuel pressure creeps up like that. Before you toss the regulator, the first thing I would check is to make sure that your return isn’t kinked or pinched or plugged up with dirt, as that would cause pressure to rise. You need an unrestricted 5/16 or 3/8 hose, with the appropriated sized and unrestrictive fittings, all the way back to the tank.
If that’s not the problem, then would switch out to the regulator to the PPE, which comes with all the fittings, or an Aeromotive which is a little cheaper (~$175) but then you have to buy fittings, which adds up to about the same or more.
Here’s the PPE:
https://www.powerperformanceengineer...tive-regulator

This is the Aeromotive that I’m using:
https://www.summitracing.com/parts/aei-13136

..That is very nice set up,did Joe make that billet fuel rail?That fuel rail does not have the hose port for the T valve relief,what Joe does is runs the stainless line down to a reducer which acts like the bleed off??? I tried to buy that SVS system but they were shutting down at the time,,,,still a wonderful piece of art and it produces a little more HP.......ED

[CI STV]

..That is very nice set up,did Joe make that billet fuel rail?That fuel rail does not have the hose port for the T valve relief,what Joe does is runs the stainless line down to a reducer which acts like the bleed off??? I tried to buy that SVS system but they were shutting down at the time,,,,still a wonderful piece of art and it produces a little more HP.......ED

Thank you sir. The fuel rail is from Ox Performance. They offer it with a 1/8” port for a fuel gauge as well, which I suppose you could install a fitting with a small (nitrous) jet to act as a bleed off. My fuel system doesn’t hold fuel pressure when I shut off the pump though, and I think that’s a feature of the pump bleeding pressure off the supply side.
I have a Weldon 1100 in-line pump (not the much more expensive upright type). Initially when I switched from the stock regulator to the Aeromotive with the stock fuel rail, I blocked the bleed-off T and it still would bleed off pressure as soon as I shut the pump down.
Here’s a picture with the stock fuel on it and one of the fuel system:

This was with the stock rail and Aeromotive regulator. Note fancy 3/8” bolt blockoff on the bleed nipple, lol. I was using a VDO fuel pressure sensor at the time. Changed to a smaller, more accurate AiM sensor now. On both sensor types fuel pressure was verified via an Aeromotive mechanical gauge on the regulator.

The fuel system is a 10AN supply from the tank, through an Aeromotive 10AN 10 micron SS filter, into the Weldon pump, 8AN fuel line through a 10 micron “Microglass” Aeromotive filter, 8AN all the way to the rail. I know it’s overkill, but it really doesn’t cost much more to have more than you need.