m35a2 fuel pump

[dropaduece]

Is a m35a2 fuel pump always hot with 24 volts, or is it pulsed. If it is pulsed what controls the fuel pump on and off.

 

[joec]

12 volts..? you mean 24volts..right..?

 

[dropaduece]

24 volts indeed, I have made the correction.

 

[joec]

Mine gets a little warm but not hot enough you can't touch it.


It's ok...

 

[dropaduece]

Do you know if the unit is pulsed or constant?

 

[bugei]

constant, should come on with the accessories switch

 

[doghead]

Dropadeuce, are you asking if its warm(temperature) or has voltage?

Joec, What 24 volt fuel pump on a deuce are you touching with your hand?

 

[joec]

Ahhh I am cheating I have a replacement on my m35. Duhh...And my M543A2 has one on the out passenger side Factory mounted bye jeeep. Right next to the tank. M35 has internal as same as driver side of M543A2.

 

[DDoyle]

As others have said, the in tank power lead is hot when the accessory switch is on. If you can't hear/see the fuel pump running, but the lead is hot, check the fuse under the cover on top of the fuel pump mounting plate.

Best wishes,
David

 

[dropaduece]

Thanks guys. I was just asking if the pump was hot/constant 24 volts or pulsed. I am now under the impression that the pump gets a constant 24 volts to it when the acessory switch is on. As the truck is running does the fuel pump ever shut off or is it always on until your turn off the accessory switch? Thanks.

Seth

 

[doghead]

It stays on until the accessory switch is turned off.

 

[mbwarner]

Your impression is correct, Drop. The pump is constant on when accessory (main) switch is on. Pump is a small centrifugal pump, and with switch on with engine not running, and with low air buzzer also not running, the pump can be heard as a hum or soft whir.

 

[dropaduece]

Sounds great. I appreciate all your help. I am getting ready to rewire the fuel pump and just wanted to make sure I had the right lead hooked up and everything did its job as it should.

Seth

 

[Stonewall]

This exactly answers a question that I was planning on asking. When I changed the secondary fuel filters, I followed the procedure in the Tech Manual, but with the bleed vent opened, I could not get any fuel / air bubbles out of the top. the assesory swtch was in the on position, but I had the air buzzer going off, so I could not tell if the fuel pump was operating. I think that I should definately check for pump flow and fuses. my truck starts / runs great, but that problem with the fuel filter changing got me to wondering... Any other thoughts on that?

 

[clinto]

From the instant you arm the electrical system to the moment you turn it off, the pump is running. So it is constant.


Excess diesel is sent back to the tank via return lines.

 

[gimpyrobb]

Stonewall, this could apply to you.

The reason I asked is, the pump can be running, but not working. There is a bottom plate that has a nasty habit of falling off. When that happens, the impeller will spin, but not pump fuel. If you got fuel out of the top bleeder, this is probably not a worry.

 

[Stonewall]

I was able to check the fuse, replace, and no luck with the pump. The truck runs well, so I let the low pressure buzzer turn off and checked the in tank pump. definately not operating. Unfortunately, it was windy and cold, so I need to ckeck out the electrical supply to the pump, but my susspission is that the pump in not operating. Any advice for quick pump fixes, assuming the electrical is fine? Where is a good source for the pump or rebuild?

 

[gimpyrobb]

The pumps are fairly easy to clean and get working again. I'd pull it out and look it over before you buy a new one.

 

[SoldierwithaM109A3]

Also If you reach under you can easily disconnect your low air buzzer under the dash . then you can hear it . or just disconnect the main line from the fuel pump and if nothing shoots out then its not working if heard

I took my Fuel pump out and cleaned it up and fixed it now it runs great.

in case others are having same issue .

 

[Parker2]

You can still by new ones from the manufacturer. I can't remember their name right now, but I'll look it up if your interested.