Lift pump pressure and voltage

jpowel29

jpowel29

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Feb 1, 2008
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Bentonville, Arkansas
One thing that I've not paid much attention to while racing was lift pump pressure and voltage during a pass. Does anyone have experience with logging lift pump pressure and voltage during a pass? I'm curious to know how much it fluctuates. I've considered testing with a "Boost a pump" set-up to increase voltage to the pump while under power.
 
ZeroGravity58

ZeroGravity58

Well-known member
Mar 23, 2008
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I don't have a guage on my current truck but my old truck would hold 15 psi at idle and drop to 3 psi on a WOT run at the track. That was a single cp3
 
jpowel29

jpowel29

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Feb 1, 2008
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Bentonville, Arkansas
Thanks for the info. I have pressure gauge that I may add inline and play around with the FASS with a boost a pump set-up. I think at WOT the CP3 could use some added pressure.
 
Burn Down

Burn Down

Hotrodder
Sep 14, 2008
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Boise Idaho
I use Spek gauges with an electronic sending unit. Most lift pumps have a port if not use the factory test port under the hood.
 
ZeroGravity58

ZeroGravity58

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Mar 23, 2008
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I put mine in the test port because that's what I consider I true reading. You have to factor in the restrictions in the lines. Your not going to see the drop at the base of the pump as much as the test port as the test port is 1' away from the cp3.
 
DetailsUnlimited

DetailsUnlimited

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Oct 26, 2009
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ZeroGravity58 said:
I put mine in the test port because that's what I consider I true reading. You have to factor in the restrictions in the lines. Your not going to see the drop at the base of the pump as much as the test port as the test port is 1' away from the cp3.
Click to expand...

You can use the test port if you still have it i guess...lol.
My LP feed directly into the cp3's.
 
jpowel29

jpowel29

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Bentonville, Arkansas
Installed an ISSPRO 30psi electric fuel pressure gauge that measures fuel pressure just before it goes into the CP3 (about 8" from the CP3 feed port). I am getting 4psi steady at idle. Pump is seeing 13.2 volts. Using a sump in my factory tank and the filters are pretty new. Factory fuel filter assembly has been removed along with the factory bulkhead/junction block that had the test port. I'm using the factory feed and return lines to/from the tank. When I crimp the return line just ahead of the FASS pump, gauge pressure jumps to about 8-9psi.

FASS is sending another spring and check ball for me to try. I am also considering removing the weatherpack connector at the pump and hard wiring the pump. I'm going to measure to see if there is any voltage drop across the weatherpack connector.
 
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Muff

Muff

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Oct 7, 2013
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Butler, Pa
All our trucks run airdogs and the pressure is adjustable on the pump by screwing in or out the adjuster with a lock nut. Fass does not have the same feature?
 
jpowel29

jpowel29

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Feb 1, 2008
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Bentonville, Arkansas
The standalone FASS pumps have an adjustable regulator. The FASS Titanium series pump systems with the filters don't. I'll start with the stretching the spring and replacing the check ball. I also have a voltage amplifier that is boost/signal referenced that I am going to install to ramp up voltage to the pump as boost/rpm comes in. I want to see how far I can push my single CP3. Once it's dialed in I'll post up some results.
 
rfletes79

rfletes79

Active member
Mar 5, 2010
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Galt, Ca 95632
My lift pump idles at 11psi, if I just stab the throttle it will drop to about 5psi, but I have a boost reference regulator......... so once it starts to make boost fuel pressure will rise to about 20+ psi full load and maintain there till I let off the throttle. Seems to work pretty good, I can't get my regulator to go below 11psi at idle, pretty sure I need a bigger dedicated return line just for the the regulator (its y into the fuel return line right now), once I get the new return in I'm sure I will have more control of the fuel pressure at idle.

The boost reference port is coming from the atmo turbo. I did run it to the high boost turbo at first and it made over 50psi of fuel pressure, figured that was way too much.....
 
bcdeutsch731

bcdeutsch731

Member
Nov 4, 2010
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Illinois
I have two AD 200 pumps. At idle pressure is 32psi and by the end of the 1/4 mile, pressure is down to about 14psi.
I'm running -10 off of each pump and right before my 12mm pumps they Y together then Y out to -8 to feed each pump. This way if one pump ever quit working the one good one will still feed both cp3's.
I have a single -8 return to the tank
 
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