M1009 fuel line question

[Winters Kamp]

Looking to go to an electric fuel pump since my mechanical one is leaking from the brass barb.
I looked under the frame on passenger side and see three lines. The one in the middle is bigger than the other two. Which line to I tie to with an electric lift pump?
Nick

 

[2INSANE]

If you go to an electric lift pump I recommend taking out the old mechanical pump and put a plate that covers where the old pump was. Make sure you take out the rod. Picture below. O’Reilly auto parts sells them.

The mechanical pump will make thumping noises if still connected to the block. Also with no fuel in it to keep it lubricated, it might seize up on you and cause unnecessary wear on your cam. It happened to me once...

F1 is your return line
F2 Rubber hose from tank to pump
The metal hose goes from pump to fuel filter

After disconnecting your mechanical pump, run a rubber hose from fuel tank line to the filter. Decide where to put your electric pump

The metal line in picture 3 goes to the back of your motor to the fuel filter pic 5

In my pjs late to get you these pictures

the electric pump you are looking for should push about 5-7 psi no more, no less

Honestly why not just replace or fix the old one? The Mechanical pump is better IMO because it produces exactly what the motor needs no matter how heavy your foot is.

Try to tighten the brass fitting to see if that stops the leak. If it does not, take off the brass fitting and line. Inspect the end of the line and check for marks that could allow fuel to seep threw. Thread tape could help as well.

 

[Winters Kamp]

If you go to an electric lift pump I recommend taking out the old mechanical pump and put a plate that covers where the old pump was. Make sure you take out the rod. Picture below. O’Reilly auto parts sells them.

The mechanical pump will make thumping noises if still connected to the block. Also with no fuel in it to keep it lubricated, it might seize up on you and cause unnecessary wear on your cam. It happened to me once...

F1 is your return line
F2 Rubber hose from tank to pump
The metal hose goes from pump to fuel filter

After disconnecting your mechanical pump, run a rubber hose from fuel tank line to the filter. Decide where to put your electric pump

The metal line in picture 3 goes to the back of your motor to the fuel filter pic 5

In my pjs late to get you these pictures

the electric pump you are looking for should push about 5-7 psi no more, no less

Honestly why not just replace or fix the old one? The Mechanical pump is better IMO because it produces exactly what the motor needs no matter how heavy your foot is.

Try to tighten the brass fitting to see if that stops the leak. If it does not, take off the brass fitting and line. Inspect the end of the line and check for marks that could allow fuel to seep threw. Thread tape could help as well.

thanks for the awesome reply! It’s leaking on the barb where the rubber line plumbs into. Thought it was a leaky line, so I replaced the line, but it’s dripping still.

 

[2INSANE]

thanks for the awesome reply! It’s leaking on the barb where the rubber line plumbs into. Thought it was a leaky line, so I replaced the line, but it’s dripping still.

Your welcome!
Corrosion on the old pump is my guess.

 

[chevymike]

Keep in mind, electric pump should be as close to the tank as possible. Electric pumps like to push fuel, not pull fuel. This is the advantage to mechanical pumps as they will pull fuel much easier. One of the reasons companies started putting electric pumps into the fuel tank. Keeps them cool and not having to pull fuel like an externally mounted one.

 

[cucvrus]

Looking to go to an electric fuel pump since my mechanical one is leaking from the brass barb.
I looked under the frame on passenger side and see three lines. The one in the middle is bigger than the other two. Which line to I tie to with an electric lift pump?
Nick

Do as you wish it is your truck. But I would stick with the OEM pump design. You are just adding complications to a relatively simple system. You can change the original diaphragm pump in less than an hour and call it fixed. Don't add more wiring and change the design because it needs a new fuel pump. But not my truck. I have over 30 years working on these trucks and have removed electric fuel pumps and went back to stock diaphragm pumps. What's the improvement? I can think of none. Just another vibration every time the key is turned on. Good Luck. Do or do not. There is no try.

 

[Winters Kamp]

I considered going back to stock mechanical pump, but after seeing the brass barb leak on the old one I figured why deal with another failure in the future. Best part was after I was done, it self primed and fired up without having to bleed.

 

[cucvrus]

but after seeing the brass barb leak on the old one

I never seen a brass barb on a CUCV stock diaphragm lift pump. Please share a picture if you have one. Must be someone's hack job. But the diaphragm pumps do have a weep hole on each side to leak fuel when they are going bad. It used to just leak into the engine oil and ruin your engine. God Luck. I hope it all works out for you. Just not seeing where this is an improvement. Take Care and Be Safe.