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-   -   Fuel Pump Issue??!! (https://www.racingjunk.com/forums/showthread.php?t=23102)

Scooterz 02-12-2009 03:53 PM

Fuel Pump Issue??!!
 
I think I need to buy & new fuel pump. My Holley manual is failing (170GPH) I think & is not enough apparently. I am getting sufficent pressure, but not enough flow at this point?? Here is a brief current setup: Sumped original tank w/ mallory filter @ tank all 10an to pump. Then 8an to reg w/ filter inbetween. from reg 6an to carb which is quickfuel 950hp. Reg is a BP w/ 6 an back to tank. BBC w/ P&P heads, teamG, solid lunatti, about 500Hp. all steel 69 Camaro w/ Th350 & stall.

Symptoms: off idle is fine. mid starts to fail & when secondaries are open for a duration, I get some flat acceleration & poping like it is lean. W/O Acceleration is poor. Carb is new (and larger than last), reg is new, new filters, plugs & wires new. floats set, jets correct, PV (only in primary) checked & is fine. Sound like a pump issue??

I need some electric pump advice. How is Holley blue/black?? I cannot afford the magna flow right now... but I want to get going soon. Have not had to buy a pump in a long time!! Any feed back is appreciated!! Scooter

twobad1 02-15-2009 08:39 AM

ive seen valve spring issues cause similar prob.just a thought

desoto30 02-16-2009 12:01 PM

Yes I would use an on engine valve spring tester & compare your readings against what you set them up at first since this is a very quick check.Then I would do a "fuel can test" to establish what the output of your fuel system actually is before forking any cash on anything,both these tests are free.

TopspeedLowet 02-16-2009 12:40 PM


Originally Posted by desoto30
Yes I would use an on engine valve spring tester & compare your readings against what you set them up at first since this is a very quick check.Then I would do a "fuel can test" to establish what the output of your fuel system actually is before forking any cash on anything,both these tests are free.

How do you do that fuel flow test on a mechanical engine driven pump? Do you use a tee in the line and then start the engine? and at what RPM, FIRE! FIRE!

desoto30 02-17-2009 08:03 AM

how I would go about this would be,hook the carb to an electric pump,with another fuel supply,connect a hose to the output side of the mechanical pump & run the engine @ chosen rpm & then look into the container each time & see how much fuel is there.Yes I totally agree with you to have a fire extinguisher at hand & I would suggest a buddy to assist also

TopspeedLowet 02-17-2009 08:35 AM


Originally Posted by desoto30
how I would go about this would be,hook the carb to an electric pump,with another fuel supply,connect a hose to the output side of the mechanical pump & run the engine @ chosen rpm & then look into the container each time & see how much fuel is there.Yes I totally agree with you to have a fire extinguisher at hand & I would suggest a buddy to assist also

Thank's Desoto30, I was just kidden about the fire, but your method sure is creative. You get an A for that answer by me sir. :) :)

TheYellaBrick 02-17-2009 09:22 AM

Stock or aftermarket fuel tank ? Stock tank will have smaller ID fuel line and a high demand engine will not allow sufficient flow to keep that carb full.

Scooterz 02-17-2009 04:11 PM

Thanks everybody. I want the Holley manual gone no matter what. The motor makes around 500hp, w/ one 4150 950hp flatform. Be it the new carb being starved or the manual pump bad, I just feel an electric is necessary. I have heard of vane style or a g-rotor style.... the g-rotor I am told is better, but requires a BP (which I have). There has to be some folks out there w/ BBC's running Holley blue or Black... on motors like mine... what is your feed back & is it enough? Keep talking to me...


Double -D,

I have a stock 69 Camaro tank that is sumped, w/ 10AN to a Mallory filter, 10AN to current pump. Then 8AN to reg, & 6 AN to carb. 6AN is BP.

Scooterz 02-17-2009 04:20 PM

Desoto-

Ok, I re-read what you are saying & now I understand it. This is mainly a wild street car driven on the street most of the time. I just don't see a pivotal point w/ valve train to cause this. I have done a visual on the heads & confirmed a .26/.26 int/ex valve lash... look good. No visible issues detected in condition of springs & valve train. Off idle is fine... it has symptoms in upper mid to full throttle. I agree with you, as you probaly know more than i anyways. heres my point: I hate mechanicals... this car warrants a electric in my opinion anyways. So no matter what, I am going to pick a pump- what do you think about holley blue/black? Thanks!! Scooter

TheYellaBrick 02-17-2009 04:54 PM


Originally Posted by Rigsby
Double -D,

I have a stock 69 Camaro tank that is sumped, w/ 10AN to a Mallory filter, 10AN to current pump. Then 8AN to reg, & 6 AN to carb. 6AN is BP.

Sounds like a tired pump alright. Time for that electric !
Just don't forget that tip over OFF switch !


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