Replace fuel pump/bleeding line

[spbM1009]

Need help with my 1985 CUCV: replaced the hard line that runs from the fuel filter on the firewall to the pump on the engine with a Jegs 3/8 I/D flex hose and fittings. Have tried the usual things to prime the fuel system (bleed the line), but the truck will not restart. Truck ran great prior to replacing the line. Just can not get the fuel to run through the system. Anyone have any ideas or tricks on how to do this? Any and all help greatly appreciated!

Stephen

 

[Gripy]

open bleeder spigot on fuel filter and hook up a vacuum pump and pump until you get fuel.

Any leaks? they would be very obvious (diesel everywhere)

Did how long have you tried cranking the motor?

ETA: do you have fuel pressure at the fuel filter?

 

[MarcusOReallyus]

Have you considered an electric pump? Takes all the hassle out of priming.

 

[evldoer]

Remove the fuel return line on the front of the injection pump. It is a rubber hose. Loosen your bleeder plug on your filter housing. Take your blow gun and blow compressed air into the rubber line. Be gentle with the air, if you put to much pressure in there you might blow something. do this until the air bubbles stop coming out of the bleeder. Tighten the bleeder, re-install the return line, and you should be good to go.

 

[spbM1009]

Thanks everyone for the responses,

I think now that I may have installed the fuel pump incorrectly. It was a dumb discovery, but I just now noticed the l pattern of wear marks on the old fuel pump arm. If I did mess up, that would explain why there's no pressure in the fuel system at all. I will be pulling that off again soon, and doing what you all suggested.

I've got a new dilemma, though. If the dowel that activates the fuel pump is too far forward (in the block), how do I rotate the crank so that it moves far back enough to reinstall the pump? Is there a special tool for this? And, any tips to make the two bolts holding the fuel pump on more accessible?

Thanks again,

 

[jholler]

If it still won't start, you might try cracking open an injector line. Mine got vapor locked when I replaced the fuel filter and drove me nuts until I figured it out.

 

[Gripy]

you push it back. You might have too take the plate off it's held on by 2 screws and rtv. put grease on the rod and push it back, the grease will hold it back there.

 

[Hasdrubal]

If your push rod isn't seated in all the way, put a socket with extension bar on one of the crank pulley bolts and you can turn the motor over.

On the lift pump replacement ; Its easier to get the rear most bolt started first as it has the worst access. Its the harder one to get in so do it first, doing the front one first can lead you to spend hours trying to get the rear bolt aligned. Just thread it on a few turns..then install fuel fitting and tighten fitting, its almost impossible to do if you do the bolts up first. Then install the forward bolt, lastly tighten the rear bolt. On rear bolt I use a 1/4" ratchet with combination of short socket and extension and just a deep socket. The clearance is very tight, Helps to put some gasket sealer on gasket so it stays in place.

 

[spbM1009]

Again, thank you all for your insight.

I have since installed an electric fuel pump, and a spin-on fuel filter. After running strong for about ten minutes, the motor abruptly stopped, so I bled the line at the exit side of the filter (the highest section of the system?) and still nothing. Not even the usual diesel mist from the exhaust pipes. So, I cracked the two injector lines at the exit side of the injection pump, cranked, and no air or diesel.

I am almost sure there is air in the lines, but I'm not sure how or where to bleed them. Do I need to remove the intake manifold to bleed the lines at the injection pump? I've already cracked each of the hard lines down where they feed the injectors. Are there any more places that I'm missing?

 

[spbM1009]

Again, thank you all for your insight.

I have since installed an electric fuel pump, and a spin-on fuel filter. After running strong for about ten minutes, the motor abruptly stopped, so I bled the line at the exit side of the filter (the highest section of the system?) and still nothing. Not even the usual diesel mist from the exhaust pipes. So, I cracked the two injector lines at the exit side of the injection pump, cranked, and no air or diesel.

I am almost sure there is air in the lines, but I'm not sure how or where to bleed them. Do I need to remove the intake manifold to bleed the lines at the injection pump? I've already cracked each of the hard lines down where they feed the injectors. Are there any more places that I'm missing?

Jholler, where did you bleed the lines when you figured it out?

 

[Hasdrubal]

First you have to figure out the fuel leak down you have in the low pressure side, as you've stated that there is no fuel at the filter bleed. You have to have fuel up to the filter before you can think about bleeding the injector lines-the high pressure side. Sounds like somewhere there is a small leak or loose fitting that is allowing air in and thus your fuel drains back into the tank. Usually on a running engine, when changing/bleeding filter, you would disconnect the pink wire from the IP solenoid to prevent air from being introduced into the injector lines. Only when you have the filter bled would you reconnect the pink wire.


As for bleeding the injectors, I place a couple of pieces of cardboard along the inner fenders, it shows the fuel spray pattern well and there's no clean up later. Remove all the glow plugs, this allows the motor to spin over faster, there's no load on the starter and its less of a drain on the batteries. Crack all of the injector lines open at the injectors. Begin your cranking cycles, I usually do 10 seconds at a time with a cooling down period. Others here have stated that you can crank for far longer. You will begin to notice fuel being spit out onto the cardboard. That's not enough to tighten injector yet. Wait until you see a good spray pattern out of each injector before you tighten it up. There are a couple of injectors which will require more cranking than all the others before they are bled. Once all the injectors show a good solid fuel spray, tighten injectors, replace glow plugs and it should fire right up.


Once its running, if you still haven't found your air in fuel leak, when you shut it down for the day, crack the fuel cap. This will release the vacuum from the fuel system that is drawing the air in. This way it will fire right up in the morning, without having to re-bleed the entire system all over. I ended up drilling a very tiny hole in my fuel cap because of this very issue as one night I forgot to crack the fuel cap. Drove it like that for over a year before I finally fixed my air in fuel system dilemma.