Lift pump operation?

[NW26]

My lift pump runs continuously. Any time the key is “on”, the pump is also. I’m wondering if this is correct? The question arose while I was searching for a replacement pump (spare), and read a few instances where people have their pump on a separate switch to aid in primming and such. Also, can you point me to a spare?

P.S. I realize the wiring is hideous - it’s being addressed lol.

 

[NW26]

It’s an ‘87 26-3 with a m12 btw.

 

[Frank Langer]

On our 1984 E30+ the fuel pump works whenever the key is on. I added a switch to turn off the alarm buzzer when I want to run the pump while bleeding the fuel line.
Frank

 

[Jerry VB]

My lift pump runs continuously. Any time the key is “on”, the pump is also.

Whenever the key is "on", the lift pump should be running - that is proper. That supplies the engine with fuel and the excess fuel cycles back into the tank.

You should never turn the key off when the engine is running because that will (may) starve the diesel of fuel and you may need to bleed the fuel system after that occurs. The proper shut off procedure is to pull the shutoff handle to stop the engine and then turn the key off.

 

[NW26]

Appreciate the input - thanks!

 

[Christian Williams]

Some engines, like the Universal 5432, can have either a mechanical fuel pump or an electric one (later models). MIne is mechancial, meaning engine-driven. I do also have an electric fuel pump, but it's used only for priming after filter changes, and it is ordinarily off.

 

[NW26]

Some engines, like the Universal 5432, can have either a mechanical fuel pump or an electric one (later models). MIne is mechancial, meaning engine-driven. I do also have an electric fuel pump, but it's used only for priming after filter changes, and it is ordinarily off.

This was my thought not knowing if I had a mechanical pump for normal operation.

I really enjoy your books/vids btw. “Alone together” is one of my favorite road trip go-to’s (audio book).

 

[ConchyDug]

Here is a link for a cheap diesel pump. You can buy a couple and have a spare. They also sell them at automotive stores for a similar price. Mines going on 4-5yrs of life.

https://www.amazon.com/CarBole-Electric-Universal-Operating-Pressure/dp/B01B7DCNBW/ref=mp_s_a_1_3?crid=17LGUEHZYLKJT&keywords=diesel+pump+12v&qid=1680279654&sprefix=diesel+pum%2Caps%2C331&sr=8-3

 

[Kenneth K]

My lift pump runs continuously. Any time the key is “on”, the pump is also.

Yeah, that's typically how they're wired. When I re-wired my engine panel, I put a 4-position start switch (accessory/off/on/start) in so I can power the panel without the pump and buzzers, but that is really only useful for electrical troubleshooting.

Much more frequently, if I haven't run the engine in a while, I let the pump run for several minutes before starting to purge the lines of stagnant fuel before cranking.

 

[william.haas]

Here is a link for a cheap diesel pump. You can buy a couple and have a spare. They also sell them at automotive stores for a similar price. Mines going on 4-5yrs of life.

https://www.amazon.com/CarBole-Electric-Universal-Operating-Pressure/dp/B01B7DCNBW/ref=mp_s_a_1_3?crid=17LGUEHZYLKJT&keywords=diesel+pump+12v&qid=1680279654&sprefix=diesel+pum%2Caps%2C331&sr=8-3

I second having a spare on board... both the in use and spare on my boat are wired with heat shrink snap plugs to simplify a quick swap out if necessary in a "situation".