Need advice

[sgt1022]

My external electric pump on my 71 c10 with 350 keeps getting hot and losing pressure. The pump is wired through a 30 amp relay. Pump is about 12 inches from the tank. My tank is still behind my seat. All lines and the pump are not in close proximity to heat sources. I have not installed a return line. I run -6 stainless braid with a filter before the pump up to a regulator set at 4.5 psi. HELP!!!

[kwmech]

Get a new pump?

[chopnchaneled]

You did not say what brand pump your using, But most electrical fuel pumps
do not like a dead head end and will run hot.
Have you noticed it clattering after you have driven it for a while, cut it off for
about five minutes then crank it back up?

[cooperhw]

You might think about installing a LS style corvette fuel filter regulator just ahead of the pump. Fuel goes through it and once filtered will continue on to the motor as needed. Any unnecessary (not needed) fuel will go out a return line on the back of the filter which you can return to your tank. This will eliminate the dead head effect which does cause heat.

[sgt1022]

The pump is only 2 months old it's a Holley blue 110 gph.

[67 cst swb]

Depending on the type of electric pump you have. Electric pumps are not designed to "pull" fuel from the tank. So, if you have that pump hooked to the original lines that come out of the top of the behind seat gas tank, you are really working that pump.
Most electric pumps are designed (read as "capable") of pushing fuel that is gravity fed to the inlet side of the pump.
I know, I know... 100's of people do it and it works. It's just not how it was intended to work. Look at any stock electric fuel pump mount location, I will be surprised to find one that is not gravity fed/supplied with fuel.
Just my .02 cents.

[sgt1022]

67 CST swb I thought about that cause it is hooked to the original fuel line coming out of the top of the tank. It really only happens when I am in stop and go traffic. I thought about switching to a mechanical pump cause I'm tired of worrying about my pump failing in traffic.

[67 cst swb]

I prefer a mechanical pump over electric in daily driver stock or mild performance applications. Diaphragm pumps (mechanical) are a vacuum creating pump. Much better for "pulling" fuel.
Remember, if there is a problem in the tank or in any part of that hard fuel line that comes out of the tank. Any pump you run may have issues.

[sgt1022]

It's a new tank and sender/pickup so shouldn't be any issues there

[67 cst swb]

Good.

[sgt1022]

I am looking at a Holley mechanical pump. The 80 gph version has 1/4" inlets where the 110 gph version has 3/8" inlets. I don't like he idea of go from a 5/16" fuel line to 1/4" inlet, seems counter productive

[67 cst swb]

Originally Posted by sgt1022

I am looking at a Holley mechanical pump. The 80 gph version has 1/4" inlets where the 110 gph version has 3/8" inlets. I don't like he idea of go from a 5/16" fuel line to 1/4" inlet, seems counter productive

That is just the NPT fitting size. You can use the 1/4"npt to 3/8" hose fitting.
Just be careful not to get too much pump and have a PSI problem.

Also, just for comparison... a typical garden hose hooked up to your house flows about 25 gph at 40 psi. Your looking at pumps that flow 80 gph or 110 gph and only needing 5-7 psi...
A stock GM Mechanical fuel pumps only flow 40-60 gph. I am betting the 80 gph will do just fine.
Holley wouldn't build a pump with fittings that were too small and kill its output.

[sgt1022]

I'm leaning toward the 80gph because my motor is a mild motor, 290hp GM performance long block. I have a RPM manifold, edelbrock 4bbl carb and long tube headers. The cam is a 450 int./460 exh. 222int/222 exh. duration at .050
I am going to put better flowing heads on in the future so I need to consider that

[67 cst swb]

That carb only really like 6 psi.
Look at Edelbrocks website. I think they have a 6 psi mechanical pump.

http://www.edelbrock.com/automotive/mc/fuel-pumps/

[sgt1022]

I have a 3310 holley 750 that's going on it. I also was going to run it through my regulator.

[67 cst swb]

ok. cool