Derranado Posted March 12, 2018 Report Share Posted March 12, 2018 Im having an issue with the fuel inhection system for my 81 720 SD22. I ended up replacing the fuel filter because I was losing power and the truck would die. Filled it full of diesel and screwed it back in. After I got it back in I've been having problems repriming my IP. Tried using the hand pump and opened my bleed screw and cracked open my injector lines but still nothing. Also the hand pump feels like its really hard to push down. Anyone know how I can get it started so it can self bleed the system? Quote Link to comment
datzenmike Posted March 12, 2018 Report Share Posted March 12, 2018 Calling wayno Quote Link to comment
wayno Posted March 12, 2018 Report Share Posted March 12, 2018 Im having an issue with the fuel inhection system for my 81 720 SD22. I ended up replacing the fuel filter because I was losing power and the truck would die. Filled it full of diesel and screwed it back in. After I got it back in I've been having problems repriming my IP. Tried using the hand pump and opened my bleed screw and cracked open my injector lines but still nothing. Also the hand pump feels like its really hard to push down. Anyone know how I can get it started so it can self bleed the system? So you need to understand that you cannot prime the injection lines with the injection pump in the off position, you can do two things to open it, the easy way is to remove the wire going to the oil pressure sensor, when that is done and you turn the key on the injection pump controller will move to the run or start position, then you can prime the injection lines. The other way is to remove the rod going from the injection pump controller to the injection pump, this opens the injection pump and you can bleed the system. What I do is fill the main fuel filter with fuel and I install it, then I finish filling it by cracking the center banjo fitting and pump the primer, once the air is out of the filter then I clear the line going to the front of the injection pump by cracking the banjo fitting on the front of the pump and pumping the primer, normally that is all I do, as the rest of the air in the lines should go to the tank via fuel return line. You must remember that most these diesel trucks came with a pre-filter, that is always what plugs up on my trucks, I get out of the truck on the side of the road where ever it died, change the pre-filter with the one I always have in my glove compartment, prime the pump for a minute and start the engine, it doesn't always start right away, but normally within 20/30 seconds, if you do not have a pre-filter then you also have have to remember you have a strainer screen in the banjo fitting on the bottom of the lift pump/fuel pump, it is a bitch to get to so that is why I have a pre-filter, it is way easier to change out a pre-filter than it is to clean that screen. You cannot use 720 gas pre-filters for a pre-filter, the diesel will not go thru that filter for long, either buy a diesel pre-filter or use the really cheap filters at the auto parts stores, just don't let them get too plugged as I have heard of the diesel fuel pump/lift pump sucking the paper element into the fuel line. 1 Quote Link to comment
Derranado Posted March 12, 2018 Author Report Share Posted March 12, 2018 Thanks man, I think I'll give that a try in the morning and see what happens. I don't run a pre filter on it, but wouldnt be a bad idea to install one so I dont end up with this issue Quote Link to comment
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