Pressure Regulator Failure

[LoBelly]

My car has a Holley Blue with a Holley fuel pressure regulator (12-803) as per the holley combo.

Went to tune the car and discovered a little gasoline fountain.

Swapped out the regulator for a new one and was still unable to stop the pressure overwhelming the carbie.

Put a fuel pressure gauge on the line to carby (after the regulator) and the 15psi gauge was pegged pretty quickly.

Is it possible that my fuel pump has suddenly got more pressure?

I notice that there appears to be a better/more heavy duty fuel pressure regulator 12-704 - anyone had any experience with this.

Open to suggestions

ta
LoBelly

[CHANMADD]

I have the same setup, deadheaded....with no problems so far......
To be honest though, the pump is noisy and I keep on thinking that I want to go back to a mechanical pump.........lots of safety advantages with the mechanical pump....Your problem has to be the pressure regulator....

[Dwight]

Coach had the same problem with a regulator a couple of weeks ago. I took it apart and found the diaphragm hard. I think the alcohol in ethanol gas is the problem. Rebuild kit are available from Summit and Jegs.

You replaced the old regulator with a new one so I would think you need to adjust the new one. If the regulator is working then you should be able to reduce the pressure even if it's twice what the pump should be putting out. It's easy to take the regulator apart to see if there is trash or something wrong. And easy to put it back together. Four screw. Watch for the spring and ball.

Dwight

[Gaz64]

Originally Posted by yw001

The news that I will one day soon be able to tank LFR and receive DPS gear to complete my off-spec set is truly welcome. I’m sure my fellow guild tank, who must always switch to DPS on solo tank bosses, will love it too.

And what has this got to do with Holley pressure regulators.

To the original poster, the new regulator could be faulty.

Even if your pump bypass jammed shut, a deadhead regulator should still be able to lower the pressure within it's own operating range.

[zrayr]

Originally Posted by LoBelly

My car has a Holley Blue with a Holley fuel pressure regulator (12-803) as per the Holley combo. ..............."
Open to suggestions

My suggestion would be to ditch the Holley fuel pump. The Holley Blue pump are notorious for being very noisy & unreliable. If you can't, or don't want to go back to a mechanical pump (the best solution for a carb'ed engine in my opinion), then try a Carter electric fuel pump. They are built better.

Z.

[Texasdoc]

Originally Posted by Dwight

You replaced the old regulator with a new one so I would think you need to adjust the new one. If the regulator is working then you should be able to reduce the pressure even if it's twice what the pump should be putting out.

Dwight

+1

If I remember correctly, the default pressure on those regulators is about 14. You can adjust it down to around 6 with the screw on the top.

[rodneym]

I have the same regulator with (originally) a Holley Red.
With the new engine install we added a Holley Black and later the regulator failed. I replaced the diaphram and all's been well but I will upgrade to the regulator for more flow (which should be used with the Black anyway). I'm pretty sure the basic small Holley reg is ok for the Red and Blue.
At any rate, the rubber diaphrams will harden or possibly tear over time. It was scary seeing my fuel psi jump from 5 tp 14 and the engine cutting out.

[Gaz64]

If your gauge maxs out at 15psi, then your pump internal bypass is jammed shut (pump is internally regulated at 14psi) AND the new regulator has some debris not allowing the ball to seat.
The 12-803 adjustment range (dictated by its' spring) is 4-9psi.
You should not be able to see above 9psi at the carb with this regulator.
Did you flush the lines after fitting the regulator?

[Rick Parker]

Replace the diaphram in the regulator with one intended for alchohol fuel, they are blue green in color.