Priming Fuel Pumps

[JeffMoss1]

Guys,

Alright...if you've disconnected fuel lines and such, can you simply reattach them and start her up??

I can't find anything that says you can't just start it after you've done work on the fuel system, but i'm not totally sure. Will it just crank for a while until it primes itself? or do you have to manually prime it somehow?

~Jeff

 

[spencnaz]

Make sure you have a battery charger on your batteries when you are cranking.

The 6.9 system is self priming but will require sometimes long periods of cranking to get the air out.

Crank the starter for 30 seconds and allow the starter to cool for at least 2 minutes to keep from cooking the starter. Also, press in the schrader valve on the fuel filter head to further purge any air from the system.

Once you get it running, feather the throttle a little bit to further purge the air from the injection system until the engine is at a smooth idle.

 

[Mr_Roboto]

Depends which fuel lines and how much air got in.

The system will purge a little air out of the low pressure lines by itself. You will need to give the engine some throttle since it won't run well with air.

If they are the high pressure (injector) lines you need to loosen the line nuts at the injectors a little to bleed the air out, since the air will simply compress and the injectors will not fire.

 

[JeffMoss1]

i'm not touching the high pressure lines at the moment. So if i replace the lines from the tank to the rough pump it should just pull it up?? I guess i don't see what other choice I have?

~Jeff

 

[Diesel JD]

Jeff, I'd disconnect the fuel lin from the filter header to the injection pump, and remove the schrader valve,a nd place a clean container to catch teh fuel between the valley pan and the filter. Then I'd crank 15 seconds on, 1-2 minutes to cool down until I had good fuel flow with no air bubbles. Then I'd tighten it back down, feather the throttle a bit once it starts, more to increase the idle a bit. Once any few minute bubbles you missed bleed out you'll be good to go. I deal with this issue often because I have an inline clear filter for my biodiesel that plugs much more frequently than the stock filter. I find if I bleed a 1/2-1 quart of fuel ot then I have good air free clean fuel to run with after each filter change. This is also what makes and e-pump nice. You might thing about an e-pump especially since you want to use WVO. Good luck,
J.D.

 

[JeffMoss1]

What would the e-pump do differently? (i assume that means electric pump) Do you not have to turn it over for it to start pumping? does it just pump when you key on?

~Jeff

 

[fsSnowboard]

i just got the electric pump installed you just key ignition on and it pumps and primes the system, then starts right up.

 

[Agnem]

Don't bother disconnecting anything. If you were working that far back, chances are the air will be right up at the schrader valve. Start the truck. It will run for a few seconds then shut off. If your right there with the shrader valve held in when it first starts, there is a good chance you can keep it running. Shouldn't take very much to get the air out.

 

[razorback]

i know this is a really old thread, but im at the process of priming my truck. just assume there is nothing in the lines, because so far there hasnt been. how long would it take to prime the system? (intervals of 30 second cranks) should it seem like its taking forever?

 

[RLDSL]

i know this is a really old thread, but im at the process of priming my truck. just assume there is nothing in the lines, because so far there hasnt been. how long would it take to prime the system? (intervals of 30 second cranks) should it seem like its taking forever?

It all depends on how much air is in the system. If the injection pump got good and dry, plan on cracking the injector line fittings loose and you could run the batteries down 2 or three times before the thing will fire.. or the thing may cough right away. there's never any real pattern to it.

Heck, I just fired my engine night before last after rebuilding and the pump had been bone dry, and i was all ready to spend a few hours fooling with it, had the big charger dragged out, cranked it 30 seconds , had fuel at 4 injectors, tightened them down, got back in and hit the key again and the thing fired up go figure.

--------Robert

 

[razorback]

i wore then down once the other day. im pretty sure its bone dry, i opened one of the injector lines and nothing came out so i know im going to have to crack them all and do that. there is a 7psi fuel pump on ebay right now for a decent price.. i might just pick that up and save myself all that headache of cranking it over and over and over.

 

[razorback]

i just bit the bullet and got a new electric fuel pump. what block off plate do i need to get rid of the mech fuel pump again?

 

[RLDSL]

Big block cheby. you should be able to pick one up just about anywhere.

 

[Diesel JD]

If you have a hot rod shop in town they'll have that block off plate, its the one for the 454. If not you can order it at AutoZone or Advance, or if you're really lucky they might have it.

 

[RLDSL]

I know they've got a couple of oreillys there on either end of town (one in town one out west in Reeds springs) that should have the thing on hand.

We're going to be in your neck of the woods later this week. With any luck at all we'll be at the Wilderness SDC campground Wed night.
-------Robert