So a new to me machine I’m trying to get running and I have some fuel questions. There are 2 fuel hose bringing fuel, 1 goes to the injection pump, and they have a in line fuel filter on it, and another that goes up to the main fuel filter where it meets up to a metal line coming from the injection pump. On the hose going up to the main filter( Orange end), they have an inline fuel pump and it’s not working. My question is that a high pressure or low pressure pump? The existing pump is rusted and can’t read any info on it. Does that pump stay on all the time or just when starting? The wiring has been hacked really badly. Any help would be appreciated.
The orange end hose should be the return, get rid of the inline pump. Check the number on the inline filter at the bottom, if it's for gas, get rid of it. Remove the banjo bolt that's sticking straight down under that priming pump, check for a screen INSIDE the bolt and clean that screen and put it back together. Unscrew the knob and pump, you should hear fuel going back to the tank, if you don't, figure out why and fix it. Once you get fuel going back to the tank, try to start it.
The pump on the side of the inj. pump is what’s “supposed to” be feeding the inj pump.. So my guess is: either it doesn’t work and they’re force feeding the inj pump OR it’s just for when they run out of fuel.. Does it have a fuel gauge.?? Does it work.?? Idk why they would have it because thats what hand primer is for.??
So I took more pictures. So the line coming from the primer pump and the orang hose go to the fuel filter on the in side, next line goes to the side of the injector and the last, highest part of the filter assembly has the out part with a hose returning to the tank, the return from the injectors and a return from a injection pump.
It has a fuel gauge but nothing in the cab is working. They really did a hack job on the wiring. It turns over but I don’t know if it’s getting enough fuel. I changed the primary and the inline fuel filters.
I retract the comment about the orange end line being the return, that's wrong, don't know how I didn't see that in the pic. Leave the orange line maybe? doesn't make sense to me or TPG, but it looks factory to me? The supply is to the bottom of the priming pump, then to the filter, then to the injection pump through the out, the return from the injectors goes to the fitting that returns to the tank that I was thinking of. None of that looks molested, so leave it all alone. Do the rest of what I said except the part about the orange end line and the electric pump. Is that inline filter rated for diesel? are you getting fuel flowing back to the tank with the priming pump operation?
I will check today if fuel is getting back to the tank, as to the filter, I’m not sure. I just bought the same as what they had on there and it never occurred to me to check to see if it’s diesel worthy. I’ll check on that today. As to the inline pump, there’s no need for it which is good since it doesn’t work. Thank you for the help.
If the inline filter is for gas it will be paper that will filter too fine for diesel. One for diesel will look similar but will be a screen instead of filter, so it will keep out stuff that will plug the valves in the primer pump, but not all the fine stuff that will get to the bigger filter. The banjo bolt screen is what the factory relied on to stop those larger particles, and works fine, as long as you know it's there when the engine loses power from lack of fuel.
I lost count of the pumps I fixed on the front counter at work, by removing that banjo bolt and showing the customer that the screen was clogged.. It still amazes me the size of the sticks and leaves that made it thru the larger filters..only to get trapped in that banjo bolt screen..
I was looking through the technical manual last night and I noticed that within the electrical schematic, it has a fuel pump (#26). Forgive my ignorance since the manual doesn’t have a fuel section and now I’m confused. It’s been pouring for the last two days so I haven’t been able to work on her, hopefully today the sun will peak out.
That's a new one on me, but that's not saying much. We'll see what TPG says? I'd have thought, the transfer pump on the injection pump is designed for the injection pump, it is a small cam driven piston pump and produces a medium pressure that is controlled by the injection pump control valves, maybe 20-30PSI? The electric pumps I'm familiar with are more like 3-5PSI and not suitable for the final pump for an injection pump. So I'd guess the electric pump purges air before cranking, then shuts off or is held off by the higher pressure of the piston pump. as long as the electric pump doesn't leak back, it doesn't matter once running?
That kind of makes sense. The non working electric pump that’s on there now is a small one. Something to think about
Update time…. I installed a new electric fuel pump, some new furl hoses, bled the system, fixed wiring and I could not get her running. She would turn over, smoke out of the exhaust but would not start. Today I decided to look at the wiring at the instrument panel. I took the seat off and found a huge rats nest on top of the control computer (I think that’s what is called). They must have been pissing on it for years! I took the computer box apart and clean the main board with throttle body cleaner. I also noticed the ground for the computer was not making contact. Anyway, cleaned and put everything back together and she finally started running! Of course it blew a hydraulic line, but it runs.