Mechanical V. Electric Fuel Pump

Matt Leaman said:

I have been using an electric on my rig since i fired it back up about half a year ago. I like it ok. wouldnt say i am in love with one over the other but my electric does the job. most of them have a filter before the pump, i learned that those can clog easily and cause fuel starvation. other than that i have been happy with it.

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First thing I did was to toss that tiny steel fitting that they call a filter, in the trash. (Or you could run a drill bit through it, end to end, so you don't have to buy a fitting.) Replaced it with an actual fitting, and a glass inline fuel filter. Even the cheapo plastic one that Cubey linked, is better than the tiny steel one.

That thing is not worthless. Worse. It is what kills the electric pumps. It clogs up right away and then you are left with starvation. And also since the pump is cooled by the fuel, the pump burns up.

I have both in my setup.

A rubber line comes off the steel line at the frame.

That goes to a wye, not a tee.

After the wye, there is a check valve on both legs.

The electric and manual pumps come after the check valves.

Then there is another check valve AFTER each pump.

Then another wye.

And from that wye, it goes up to the fuel filter.

Selahdoor said:

hTat thing is not worthless. Worse. It is what kills the electric pumps. It clogs up right away and then you are left with starvation. And also since the pump is cooled by the fuel, the pump burns up.

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My F250's pump has done fine with a plastic filter then the tiny metal one for over 15k miles since I bought the truck with the pump already on there. The plastic filter is what saves it. Yeah not having it there would be better but on my setup it hasn't hurt anything.

Cubey said:

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The wix number for that filter is 33003



EDIT: did find what looks to be a good reuseable pre filter sometime back

https://www.speedyracer.com/SILVER-...usable-SS-filter-AN6-AN8-AN10-Inline--1007704

Selahdoor said:

First thing I did was to toss that tiny steel fitting that they call a filter, in the trash. (Or you could run a drill bit through it, end to end, so you don't have to buy a fitting.) Replaced it with an actual fitting, and a glass inline fuel filter. Even the cheapo plastic one that Cubey linked, is better than the tiny steel one.

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I think of some those have a smaller version of this type cone filter, was going to use this as a prefilter but have found them to be horrible with the one that was in the holley on the f100.

I run a mechanical pump, but after it died when I first bought my truck, I run an in-line electric pump as a back up, just in case the mechanical one dies again. And it's convenient when you need to prime the fuel system, without killing the Batteries & Starter.

420Bullnose said:

I run a mechanical pump, but after it died when I first bought my truck, I run an in-line electric pump as a back up, just in case the mechanical one dies again. And it's convenient when you need to prime the fuel system, without killing the Batteries & Starter.

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That's exactly what I do.

i have seen holley red mentioned several times but i don't find one for diesel
i looked at https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/fuel_pumps/ and selected diesel fuel type
i use a https://www.holley.com/products/fue...s/carbureted_electric_fuel_pumps/parts/12-430
been running for about 6 years

grumpy1 said:

i have seen holley red mentioned several times but i don't find one for diesel

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Yeah it's not listed as being compatible with diesel but people like myself seem to run it fine. I suspect it's a marketing thing.

grumpy1 said:

i have seen holley red mentioned several times but i don't find one for diesel
i looked at https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/fuel_pumps/ and selected diesel fuel type
i use a https://www.holley.com/products/fue...s/carbureted_electric_fuel_pumps/parts/12-430
been running for about 6 years

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Be carefull that pumps psi is at point it will mess with the internal variable timing of the injection pump and can mess with alot of stuff like EGT's black smoke and much more I was always told to stay 7-8psi max pressure preferred is 4-6psi and try to keep it from ever dipping under 4psi if possible the reason being it can cause issues remember our injection pumps get hot and the fuel coming in is much cooler as you drop the pressure closer to 0psi there is increased risk of cavitation inside the transfer pump and into the high pressure side of the injection pump ( aka will cause fuel to foam ) this can have catastrophic outcome it will cause injection pumps to die and well odd performance and hard starts and such and rapidly degrade the injectors and injection pumps PLZ for the love of god keep the minimum PSI above 4psi modern diesel don't do the same as the old diesel our engines / injection systems were designed for modern diesel is designed for super high pressure in the several 1000's of PSI old diesel was designed for injection systems 1750psi ish like our engines have.

I want to point out modern diesel is much drier and evaporates quickly compared to old style of diesel add to it modern diesel fuel is designed to turn to vapor / gas easier meanign it easily will turn so in the fuel system of our motors modern diesel essentially has a much lower boiling point it readily turns to gas / vapor at a much lower temperature so a rapid decrease in pressure going into the injection pump into the transfer pump and rapid heat up = vaporizing this is why you do not want to ride the edge and run below 4psi inlet pressure to the injection pump / transfer pump. This was all explained to me by a retired NASA aerospace engineer that designed alot of stuff in his lifetime he walked me thru the entire design of these injection pumps top to bottom in and out and explained everything in detail he was the guy i got my marine injection pumps from for our motors that are super rare they are essentially a hybrid db2 / DB4 injection pump if remember correctly.


service bulletin 304R9 http://www.stanadyne.com/dealerportal/ssi/english/Training/99687 Part 1.pdf July 18, 2005 they revised our transfer pump blade design for newer diesel aka low viscosity diesel and have not really done much since to address issues and most of the injection pumps are still being rebuilt with the old style blades so it compounds the issues hince 4psi minimum inlet pressure needed to reduce cavitation inside the transfer side of injection pumps modern diesel is essentially low viscosity diesel and again our engines were not really designed for it.

https://wiki.anton-paar.com/en/diesel-fuel/

1mouse3 said:

I think of some those have a smaller version of this type cone filter, was going to use this as a prefilter but have found them to be horrible with the one that was in the holley on the f100.

You must be registered for see images attach

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Found a pic of one of those type filters that came out the holley and never went back in. It keeped getting a build of a strange sludge on it that would clog it up.

I have both in my system. I run full time on the mechanical but have an electrical on a toggle switch that I primarily use to bleed the system on fuel filter changes but it also can be used as a backup pump if the mechanical fails ( I just went through this as my mechanical did fail after 35 years of reliable service).
I personally prefer running on mechanical pumps but don't have an issue with electric ones either. As long as they get the job done I am happy.

KevSrFord said:

it also can be used as a backup pump if the mechanical fails

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They can really save your bacon by getting you home. I've done this myself.

IDIBRONCO said:

They can really save your bacon by getting you home. I've done this myself.

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I just did it. I actually ran for a few days on the electric pump till I crawled under the truck to install the new mechanical pump. But my primary reason for the electric pump is for bleeding the fuel system if I have to change the filter out in the sticks and don't get the filter filled up before installing it.

KevSrFord said:

But my primary reason for the electric pump is for bleeding the fuel system if I have to change the filter out in the sticks and don't get the filter filled up before installing it.

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Same here. I only ran mine on the electric long enough to get home that evening, to Auto Zone the next morning (to pick up a new mechanical lift pump), and then on to the shop at where I was working to get the new pump installed.

Might as well lob myself into the crossfire here...

First, I must mention that come spring thaw the box is coming off old cluster-truck and every single fuel line, valve and fitting will be stripped out, repaired where sensible, replaced and/or upgraded, from the shower head to the Injectors with an eye towards fuel changes likely coming down the pipe over the next 10 years. Both tanks are going for a soak in the tank our local rad guy uses as a substitute for divorce and if suspect replaced with custom build, coated tanks. But I digress...

I find arguments in favour of utilizing the best of both mechanical and electric persuasive and will be doing just that, using a low pressure (6-9psi) high flow (~200gph) Carter on the frame rail in front of the tank selector, with a pressure regulator and quality inline filter, as well as a new oem mechanical lift.

I've always found when confronted with two sound and logical schools of thought, do both. I also like the idea of valve isolated systems for each but again I digress. The primary system will be the mechanical, with the electric available as needed. Should afford me ample room to start monkeying around a fair bit.

The way I look at it any money I might otherwise have spent on ignition parts can be tossed into the diesel soup pot. It also helps that this truck is worth throwing money at. I hope my shaky reasoning is of use to the OP, if not I'll go soak my head in the aforementioned solvent tank.