Adding an electric priming pump.

Here's a quick video showing how to add an electric priming, or back-up, pump to your diesel skoolie or coach conversion. An electric priming pump is super handy for those times when you change your fuel filters or, egads, when you run out of fuel.

[davidjones]

Yet another golden nugget of informative information you have imparted with the wider world. I have fitted electric fuel pumps in the past, but had never thought to do it this way before.
Many thanks.

[firoznanji]

Well explained, planning to install it in my diesel car. will stop having to prime all the time.

[thetslabus]

I never knew such a thing existed! Very cool, next time I'm doing mechanical work on my bus I may have to integrate one....
PS Love the "throw me under the bus" reference - I use that quite a bit :)

[anomalous]

Terrific explanation. The diagram was a great help.

[blakedewhirst]

awesome info and idea...curious how long you let your bus sit in the winter...do you start it up regularly or just sit for a bit..how long between drives in the winter..its hard to take on regular drives in the winter in nova scotia canada..love your vids...

[kennyh]

I got so sick and tired of having to prime my diesel to get rid of air in the line and the pump gets air locked and will not pump out the air, so now bought a fuel pump for under $25 and will use it to bleed the air out of the lines! That's the only time it will need to be used. Saves wearing down the battery and screwing with it for hours trying to get all the air out of the lines so it will start and run reliably!

[InternetDude]

FYI you can buy "flow through" fuel pumps so you can just put it inline and not need the extra lines and check valve. For gas engines, anyway. Not sure if it's the same for diesel.

[juniperwildflowers]

When would this setup be useful? You make it look so easy, I want to try it but not sure when I need to use it.

[coachgeo]

faucet makes pumps for diesel that allow free flow thru them so you do not need all that plumbing. pump price comes in less cost wise by time one adds all extra fittings and check valve to make a bypass. Took me weeks staring at websites to find a pump with a high free flow thru with pump off claim. Hope below helps others in making decisions.

Was important to me to find a "free low thru" pump just so could eliminate extra potential air leaks, that one ends up with by plumbing in a bypass. Free flow amount was important as well to reduce or have no restrictions to fuel flow. .. In line with that idea.. keeping EVERYTHING similar ID thru whole system was my (stupid?) goal. Again If yall dont care about few more hose clamps (thus more possible air leaks )or restriction to fuel then stick with standard fuel line system and a Faucet Purlator pump that states to be a free flow thru.... and it will be very reasonable in cost... No bypass needed (though you will need a check valve).

My not wanting any additional restrictions via step down and back up to the systems fuel line ID, cost me ton more. 99% of pumps actually have smaller ID ports on them at each end, than what your fuel lines actually are. Pumps fittings you use, is what step it back up to your preferred fuel line ID. Each end of pump port is usually closer to 1/4 inch. My fuel system lines are closer to 3/8 so went with 3/8 npt ported facuet pump. No restrictions thru the whole system by variable sized ports. Vehicle fuel return is 1/4 inch.

Sadly though; at needed lower pressure applications in old diesels like ours, AND to meet my (stupid?) same fuel system ID goal; Facet was the ONLY pump with 3/8 npt ports on each end but also only available in a 24v at that size port. Again, If one does not care about same ID thruout; the options are greater, such as the one he used in this vid. I just got a 15buck step up to 24v converter. A negative with faucet though. is their weird micro rating for prefilter requirement of 74 micron or less. if going AN fittings... nothing on the market fits well to that. unless again if you dont care about hose clamps and flow restrictions.... In that case your fine if you just use the prefilter w/ hose barbs most pumps manufactures recommend. 80+% of inline fuel pumps out there are high flow, high pressure pumps for modern Injection systems.. (aka.. more susceptible to damage) yet require only a 100 micron prefliter... so the in line AN type prefilter market is created around that. These common high pressure pumps dont work with older diesels without adding a pressure regulator that are as costly or higher than the pump itself. This meant that sticking with the Faucet; the closest match to the 74micron inline AN type cleanable stainless mesh prefilter said to work with diesel, is a 40 micron filter. Going to that small a micron one will have to clean it more often. I bet pump he used here actually requires a prefilter too.. not sure why he chose not to use one. Companies package them separate hoping you dont buy one.. then you damage your pumps more often and they sell more pumps

Myself Am gambling in using a 50 micron PETROL Pre pump filter (not rated for diesel). Further up line; after pump, a 30 micron stainless mesh cleanable filter that is replacing the OEM inline filter... prone to be an air leaker. Then on to the OEM spin on 10micron filter.. All in all, fairly minimal fittings used. Fittings that screw together and (supposedly to be) forever non leak joints. with hose that (supposedly) will never break down inside.... hopefully I will never get an air leak in future. If had gone with traditional rubber/steel lines again, I'd be pushing 90-100+years old by time that system becomes lots of air leaks again / ages out in the rust belt where I live; thus all needing replaced completely again.. I wont be up to that task then. With AN fittings and PTFE hose hopefully am avoiding that. Cleaning wise of stainless mesh filters.... should be easy to remove inline screw together filter's so should be OK doing that till I croak.

Via AN fittings am using AN fitted checkvalve to keeps system primed when engine or elec. primer pump is off. It will go inline similar to what he did here. Any diesel system should have that .... bypass or not. Keep in mind most inline pumps have check valve built in (thus why restricted or no free flow thru them) so with those your your back to HAVING to have a bypass system if your intent is for it to be ONLY a primer pump. If it is your ONLY pump from tank to IP or Governor.. (aka you bypass your mechanical fuel pump) then you will not need a check valve. In c an added elec. primer pump design .. , normal driving would use mechanical pump on the engine. Advantage to that over full time electric, you can roll start and drive; if I have too on a bad day. Again, Free flow thru type elec. pumps do not have internal check valves so; like bypass system, you have to put a checkvalve somewhere to prevent un-priming/bleed back to tank.

??where to put checkvalve when using elec. primmer pump?? and not a bypass system .... maybe just between pump's prefilter and the pump??? so almost whole system wont loose prime when pump or engine is off.? Keeps check valve semi protected by a filter, too.... but then again. everything ahead of that un-primes / makes a mess, when cleaning/ changing any of your inline filters.. If one can put two checkvalves.? one like suggest above... and one right after last of the inline filters, far back as possible from engine but still after final inline filter between tank and then less stuff un-primes/makes mess when dealing with the inline filters... Myself am not pocket thick so cant do that. Now sure which way I'll go ???? Besides mess. not a huge deal though.. can use elec. primer pump to reprime everything after any filter cleaning... Priming is what it is there for.