low fuel pressure today???

[BullF-16]

Twin turbo LSX 427 running Squash Dual 400LPH pumps and return style with aeromotive rails regulator etc.

Normally rock solid at 43psi, but today it read 14psi on the way home from work. Adjusted the regulator as far as I could and could only get it to 22psi.

I also run an inline aeromotive 40micron filter that hasn't been changed for about 15K miles and i do run 16 oz of Torco per tank.

What could it be?

Danke

[Gearheaded]

Have you tried changing the filter?

[AGP Turbo]

bad regulator

[BullF-16]

let it sit for a couple hrs and just tried it. Wont get past 2 psi and will not start. Could it be the regulator. I can hear the pump when i key it on.

[BullF-16]

Originally Posted by Gearheaded

Have you tried changing the filter?

I was gonna do that but now it wont build any pressure or start. Also if the filter was getting gunked up, i would think it would be a gradual noticeable pressure drop over days. This just started today. My start routing is to key on and let the FP gauge build to the normal 43 psi then start it up.

Today after work, it only built to 14psi and stayed there for the drive home. Now no pressure

[BullF-16]

Went back out and turned on the key, disconnected the oil scavange pump so i could hear the fuel pump better. I could hear the pump running but nothing at the regulator, no fuel flow or not noticeable. After about 2 minutes while under the hood i heard a change in the fuel pumps noise, basically an increase in noise and a little bump in frequency. I could also hear some flow at the regulator.

Went to check the FP gauge in the cockpit and it was up to 16psi. Car fired right up. Shut it down, turned key on and went back to 16psi. Before it was way down at 2psi and would not start.

This sounds like maybe a pump issue?

[2010_camaro]

I had a similar problem with my twin 450s. I had a pump fail.

[swiftkart]

I had the same issue with my Squash, 2 dead 450's pumps, one 5 psi the other 14psi, check your pumps, unplug the main pump that is only giving you 2 to 16psi from the battery, then unplug the hobbs switch and jump the wires and see if the secondary pump puts out your 43psi setting, if it does your main pump is toast, if it doesn't you may have loss them both like I did.

[stevieturbo]

Originally Posted by BullF-16

Twin turbo LSX 427 running Squash Dual 400LPH pumps and return style with aeromotive rails regulator etc.

Normally rock solid at 43psi, but today it read 14psi on the way home from work. Adjusted the regulator as far as I could and could only get it to 22psi.

I also run an inline aeromotive 40micron filter that hasn't been changed for about 15K miles and i do run 16 oz of Torco per tank.

What could it be?

Danke

That's a substantial drop. Is it having an effect on how the car runs ? Fuel trims ?

If not, then I'd be testing whatever you're using to measure pressure. If so, then yes start checking pumps, hoses, fittings etc.

Although a drop to only 14psi...I'd be surprised if it did actually run.

DO both pumps run together ? staged ? If only one, can you manually activate the other pump ?

Can you test for voltage to each pump...or if separate wiring even better monitor current for each pump to see how hard they are working ( if at all ). Simple clamp meter is handy for this.

[Gearheaded]

Sounds like pumps or regulator. Either way I wouldn't run it too much until I checked both out.

[BullF-16]

Seems like its a check ball that is too soft and lodging internally. Its the check ball that prevents hot fuel to backflow thru the pumps and into the tank after shutdown.

When jumping the hobbs the 2nd pump is enough to kick the ball out and the car runs fine on the primary pump. Then shutting it down, the check ball that is too soft gets lodged again and limits the psi when the car is warm.

Let it sit 24 hrs (fuel and check ball cool and shrink) and it again runs fine until shutting it down, the residual heat in the fuel expands the check ball and it get wedged in the inlet again.

Anyway, Andy has been outstanding and is waiting for me to send it back into him free of charge. It seems there was a batch of units that went out long ago that has the out of spec check balls.

I have about 22,000 miles (3 years) on this set of pumps btw and its been able to feed the motor well.

FHRC

[jasycz28]

Originally Posted by BullF-16

Seems like its a check ball that is too soft and lodging internally. Its the check ball that prevents hot fuel to backflow thru the pumps and into the tank after shutdown.

When jumping the hobbs the 2nd pump is enough to kick the ball out and the car runs fine on the primary pump. Then shutting it down, the check ball that is too soft gets lodged again and limits the psi when the car is warm.

Let it sit 24 hrs (fuel and check ball cool and shrink) and it again runs fine until shutting it down, the residual heat in the fuel expands the check ball and it get wedged in the inlet again.

Anyway, Andy has been outstanding and is waiting for me to send it back into him free of charge. It seems there was a batch of units that went out long ago that has the out of spec check balls.

I have about 22,000 miles (3 years) on this set of pumps btw and its been able to feed the motor well.

FHRC

Did you get this issue straightend out yet?. I seem to be losing my main pump but I haven't had the chance to test the secondary pump.