New electric fuel pump install

[coolhand75]

Hello everyone I have a 75 j10 and have been having fuel delivery issues. Someone put a single in and single out fuel filter after the mechanical fuel. I believe it’s supposed to have a vapor line out of the fuel filter and I think it’s causing it to vapor lock even in the winter. I have a new electric fuel pump I would like to mount in conjunction with my mechanical. Should I run it if a relay and where and should I use a fuse tap. Just wondering what you have done.


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[Stuka]

What symptoms are you seeing?

Where is the filter located? Is it near or touching the engine? If so, thats why its getting too hot (if thats the issue). A glass filter can also be handy to see if you are actually having an issue with vapor lock.

A electric fuel pump will not solve this issue if it is vapor lock and the fuel pressure will be too low to change the boiling point much.

[will e]

What carb are you running? The stock setup or an aftermarket?

[ghcoe]

Electric fuel pump solve all my vapor lock issues. I am running a relay under the hood and 10 gauge wire back to the pump. Pump is mounted on the rear frame rail just behind the tank. I used a Precision pump https://www.oreillyauto.com/detail/prec ... +fuel+pump .

You should have a filter with a return line.

[coolhand75]

What symptoms are you seeing?

Where is the filter located? Is it near or touching the engine? If so, thats why its getting too hot (if thats the issue). A glass filter can also be handy to see if you are actually having an issue with vapor lock.

A electric fuel pump will not solve this issue if it is vapor lock and the fuel pressure will be too low to change the boiling point much.

Hi it’s one of those plastic see through filters right of the carb under the air cleaner. The fuel spurts in never fills the filter all the way up about 3/4 or so. A few weeks back it was plum full I thought my issue was fixed and it came back. I noticed in the tsm it’s supposed to have a three line filter.


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[coolhand75]

What carb are you running? The stock setup or an aftermarket?

Holly 600cfm


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[coolhand75]

Electric fuel pump solve all my vapor lock issues. I am running a relay under the hood and 10 gauge wire back to the pump. Pump is mounted on the rear frame rail just behind the tank. I used a Precision pump https://www.oreillyauto.com/detail/prec ... +fuel+pump .

You should have a filter with a return line.

I take it that’s what you have on yours. A three barb fuel filter?


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[coolhand75]

This truck set for a long time. And I had someone work on it that was sub par. It used to run like a top no timing issues no fuel issues it’s like a different truck. I’ve made another post awhile back about my fuel problem. This thing will actually run it’s self out of fuel. I carry a one gallon gas can around with when this happens to fill the carb through the vent tube. At idle sometimes no fuel is coming out rev it up to 1500 splash splash it comes out. Thanks for helping


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[will e]

Get yourself a fuel pressure gauge and place it between the filter and the carb. This will be invaluable to troubleshooting your issue. Better still is to install an electric gauge so you can monitor from the cab.

With my Holley I found it worked better without a fuel filter that had a return line. The fuel filter with a return line resulted in about 2 or 3 psi of fuel pressure, a straight through put me closer to 6 psi. This is all with an electric pump.

[ghcoe]

Electric fuel pump solve all my vapor lock issues. I am running a relay under the hood and 10 gauge wire back to the pump. Pump is mounted on the rear frame rail just behind the tank. I used a Precision pump https://www.oreillyauto.com/detail/prec ... +fuel+pump .

You should have a filter with a return line.

I take it that’s what you have on yours. A three barb fuel filter?


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Yes.
The return line keeps the fuel cool by keeping a constant flow of fuel moving through the system. A electric pump near the tank keeps the fuel in the line under pressure therefore reducing vapor lock conditions.

[Stuka]

What symptoms are you seeing?

Where is the filter located? Is it near or touching the engine? If so, thats why its getting too hot (if thats the issue). A glass filter can also be handy to see if you are actually having an issue with vapor lock.

A electric fuel pump will not solve this issue if it is vapor lock and the fuel pressure will be too low to change the boiling point much.

Hi it’s one of those plastic see through filters right of the carb under the air cleaner. The fuel spurts in never fills the filter all the way up about 3/4 or so. A few weeks back it was plum full I thought my issue was fixed and it came back. I noticed in the tsm it’s supposed to have a three line filter.


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That doesn't sound like vapor lock. If the filter is see through, you would see the fuel boiling if it was vapor lock. It sounds like you have a failing pump, small cracks in the lines that let the pump suck air (but not leak fuel, not uncommon), or the pickup in the tank is maybe getting plugged.

EDIT: Its also possible the pump is pushing fuel passed the needle and seat because there is no return line. This would result in rich conditions which can also cause the engine to stumble.

[ghcoe]

,....

[kansasboy001]

Sounds redundant but it works. Get a bypass pressure regulator and set it for 4.5 psi. Hook the return from the stock filter to its return and run a single fuel filter before the regulator. Fixes everything.

[will e]

I have a see through filter on my 73 Mustang. There are often times it isn't 'full' of fuel.

Before you start throwing parts at it. Get a fuel pressure gauge. Information is everything.

[Stuka]

I have a see through filter on my 73 Mustang. There are often times it isn't 'full' of fuel.

Before you start throwing parts at it. Get a fuel pressure gauge. Information is everything.

Exactly. I have a glass filter on my J10, its never full.

I really do not think this is vapor lock. Its either starvation due to my above stated reasons, or too much fuel. Either way, a pressure gauge will tell us.

[coolhand75]

What symptoms are you seeing?

Where is the filter located? Is it near or touching the engine? If so, thats why its getting too hot (if thats the issue). A glass filter can also be handy to see if you are actually having an issue with vapor lock.

A electric fuel pump will not solve this issue if it is vapor lock and the fuel pressure will be too low to change the boiling point much.

Hi it’s one of those plastic see through filters right of the carb under the air cleaner. The fuel spurts in never fills the filter all the way up about 3/4 or so. A few weeks back it was plum full I thought my issue was fixed and it came back. I noticed in the tsm it’s supposed to have a three line filter.


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That doesn't sound like vapor lock. If the filter is see through, you would see the fuel boiling if it was vapor lock. It sounds like you have a failing pump, small cracks in the lines that let the pump suck air (but not leak fuel, not uncommon), or the pickup in the tank is maybe getting plugged.

EDIT: Its also possible the pump is pushing fuel passed the needle and seat because there is no return line. This would result in rich conditions which can also cause the engine to stumble.

I’ve bypassed the fuel tank using a gallon gas can and it seem to work fine but now that you mentioned rich conditions it also has that I think I should try the return line setup. Cross your fingers. Thanks


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[coolhand75]

Thank you everyone for all your input


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[coolhand75]

Update
I installed a new electric fuel pump today I’m still have the same issues. I thought the electric pump would push fuel past the mechanical one but it doesn’t seem to. When the engines cold they seem to fill the filter fully once the engine gets to operating temp they don’t keep the filter full. Help!!!


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[coolhand75]

https://youtu.be/8z0M6i4Stfk

Here’s a short clip if it helps


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[letank]

Update
I installed a new electric fuel pump today I’m still have the same issues. I thought the electric pump would push fuel past the mechanical one but it doesn’t seem to. When the engines cold they seem to fill the filter fully once the engine gets to operating temp they don’t keep the filter full. Help!!!

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your mechanical pump should be off the circuit, mine is not on the fueling hose circuit. Now the mechanical fuel pump is removed and a cover plate has been installed on the timing cover