Does anyone use electric fuel pumps on their diesels? Thinking of reworking my fuel supply system and either ditching the water seperator, or getting a new aftermarket one.
I got several electric pumps laying around I could use. Got a couple Holley red pumps and a mallory pump.

 

That's a very popular mod. These trucks have a lot of air intrusion problems and putting in an electric fuel pump can get the fuel pressure up and eliminate air pockets in the fuel stream which minimizes no-start problems, especially if you turn on the key and bleed the schrader.

Some guys leave the mechanical pump as is in the fuel stream and some take it out and block off the engine block mounting hole with a little cover(I think the chevy one fits right on). Some people also remove the water separator in the earlier trucks but some accommodation should be made to remove water. Racor sells a filter head that can mount to the firewall and then of course they also supply the filters with a bleed valve that fits it. If you don't have a means of getting rid of the water your pump and injectors will suffer and fail prematurely. The biggest cause of failure is attributed to water in the fuel causing rust inside the components when the truck is sitting. Then upon start-up the terribly abrasive rust is processed through the injection pump thereby wearing down the internals of the pump. The rust will also develop inside the injectors, plugging and pitting the tips and messing up the spray pattern. If the injector is just clogged, cleaning can help but when rust is there for a while it causes other rust to form and the inside of the tip will quickly pit and mess up the spray pattern even after it's cleaned out.

 

Sweet, thats what I was hoping to hear.

I just got to figure out what I am going to do for a water seperator now.

 

If you mount electric pumps, get rid of the stock pump.

A ruptured diaphram could fill the crankcase with fuel.
That is not a good lubricant for the engine.

 

I did the Holley red, then put a Chevy water separator from an 83 6.2 that mounts on the firewall onto the stock location of the separator on my 86. Almost a straight bolt up, a little finagling and shimming, but it mounts. Relatively cheap too.

 

What kind of presure do the Holley red and Mallory put out?

 

The holley is about 7psi and the mallory is about 10psi, and I got regulators that I can turn em down if needed.

What is ideal for these motors?

 

Use the Holley, 7 PSI is plenty.

 

Can you have to much pressure? I checked the fuel pressure a few months ago and it was either 3 or 4 psi.

 

Fuel pressure inside the IP affects the injection timing.
So yes, you could have to much pressure, but that would have to be moving more fuel than the return line could carry.
That is not that much out of the question, the return line is not that big.

 

I used a used "Facet" pump. We had used it to provide gas to a 11hp briggs and stration on an older skid unit. I cleaned it up, inside and out.
Mounted it on the frame rail just beside the mech pump. Got 12v power from the fuel selector switch. It runs all the time the key is on, but the fuel keeps it cool. Moved the rubber line from the input of the mech pump to the input of the Facet pump. Then a short piece of rubber line from the out side of the Facet to the in side of the mech. (yeah, I know Dave's warning).
I think this model provides about 5psi. It will prime the system just with the key on. It will pull fuel from 2-3 ft below. It also has a built in check (ball) valve to keep the fuel from falling back to the tank. I also tested to see if the mech pump would continue to fuel the engine if the Facet failed by disconneting power, it did.

 

I'm using a pump I had that has an output of 5-9 psi for SVO. I don't remember what the original application was.

 

I used a purolator 7 psi 32 gph pump $28 at schucks.

 

I have fitted a NAPA electric fuel pump, and a second new inline filter mounted before the pump so no water / dirt could enter pump, and disconnected my mechanical pump, but still retain the original fuel filter. The new electric pump has an operating pressure from 6 to 9 psi and 23 gals per per hour. Only problem I experienced was the higher pressure, mechanical pump rated at 4 to 6psi, blew out the fuel return check valve in the top of the fuel filter and caused some hidden mystery drama for about 2 hours until problem identified and replaced. On road performance improved slightly but starting is much faster as pump has created maximum fuel pressure through the top fuel filter and in the line to the injector pump before I engage starter motor. Very satisfied with the change to electric pump.