Hello all. I am working on an old gradall with a John Deere power tech 4.5 ser#PE4045H468706. Original complaint was it was run out of fuel. I am able to get it bleed and have it running strong but after it sits for a couple hours it looses prime and I have to bleed it again. In the course of working on it all the supply lines have new seals. Is there a check valve somewhere in the system I need to look at? I really have no idea where to go from here. Any suggestions? Thank you for reading.
Any rubber suction hoses? those crack and leak air and then you're screwed, the lift pump won't suck air very well. The lift pump is the most important check valve that I know of, but it could leak back before the lift pump with a suction hose leak. How's the fuel tank? any chicken skin, rust, water? is there a screen in the tank?
Good morning Delmar. The rubber suction hose from tank to prime pump is brand new. Tank appears to be clean, no water / rust. Not sure what chicken skin? I suppose it could be the prime pump. I assume the lift pump is what I'm referring to as the priming pump? The hand pump right before the water separater?
Yes, is this lift/priming pump mounted on the side of the engine, on the camshaft? Chicken skin is wrinkled varnish that forms in bio diesel. You could try pumping the priming pump before starting, without bleeding it. I don't know how to test the pump without "throwing parts at it".
If the priming pump will come apart, do it & check the valves to see if there’s anything holding them open.. If not, replace it..
U could try pumping it up before starting it to save crank time on the starter until the new pump arrives.
Thanks guys, I'll try the pumping before starting thing.
If you have a water separator filter with a glass bowl, check to make sure the o-ring is between the filter and the bowl. I have seen this mistake made numerous times by customers who changed their filter and not moved the o-ring over creating hard start complaints due to air incursion.
Thanks for the tip, except no glass bowl. It's a replaceable filter cartridge.
Where your Is your filter head. Pre or post fuel pump ? Get a pair of hose pinch pliers. Run unit and pinch of your main fuel sunction line at what ever it feeds first. Then wait for the time frame your seeing it loose prime. Start the engine and see what happens if your able to start it and dont have to bleed the system you know its bleeding off of the supply side. Do you see any smoke after starting up ? Like maybe you got an injector thats bleeding off ?
As a matter of fact I do see black smoke after I get it running. Most pronounced when you aggressively reave the engine. I did the crimp test, it would not start. The line was crimped right after the tank, before the filter, transfer pump, and water separator.
Now do the same test with the fuel return line.
Black smoke when increasing the rpms quickly especially when your doing several times in a row is normal. Like mg said try the return side and see if you can isolate where exactly your loosing it.
Thanks for all the replies! So, did the crimp test, both the supply and return hoses where crimped. Still no go. Scratching my head how that can be????
This is beginning to sound like a different problem. Are you positive that it is losing prime? What exactly are you doing when you attempt to restart this engine after it sits for awhile?
I bleed it at the injectors. Grasping at straws here but....... I never have bleed the fuel pump where the return line is connected to the fuel pump due to limited access. I bleed it at the bleed screw on the filter/separator. Then bleed the injectors. Do you think I could have a pocket of air trapped in the injection pump? I'm going to get the seals for those two lines (supply & return) where they connect to the pump and try bleeding it. I'm replacing the seals because when I cracked the other fuel lines (at the fuel filter/separator) the seals crumbled and came apart.
Its doubtful you have an air trap if your engine runs after you bleed the fuel system. Replaced your lines seals then see what happens.
U still haven’t replaced the supply pump..
Yes, I changed the prime pump.
Sorry musta overlooked that.
No, I neglected to post that I had replaced it. My apologies. So, I've changed the fuel fillter (in line type between tank and prime pump) the prime pump, and the seals for the supply lines. I've also triple checked the seal on top of the fuel filter/separator.
So I replaced the seals on the supply & return lines at the injection pump. Re bleed everything. Got it running actually the best it had ran the whole time. Before when I'd get it running it always seemed to have a miss. Tryed to start 4 mornihours nextlater,ng it started and ran fine. Wouldn't start the next morning though. Thinking I should change out the fuel filter base next? I hate being a parts changer.......
Does your machine have the 4bt cummins ? You said it didn't start again in the morning after sitting up for the night ? Did you have to crack the injectors to get it fire up ? Just one more thing you could try is getting a cheap inline fuel pump and remove your fuel system from the loop. Put a nut on new piece of fuel line to make sure it stays in the fuel and just drop it into the tank via the fuel filler. Put in a filter then run straight to the injection pump. It will by pass your stock filter and associated parts. Just a thought... Sounds like your on track to get it nailed down. Have you pulled your filter off before even trying to start it first thing for the day to see if you have full filters ? Might help narrow it down a little. How many hrs are on you machine ? If the filter base does not correct you issue you might consider getting you injectors bench tested. Just throwing out some possible ideas at ya.
Have u tried pumping the hand primer before starting.?? IF it starts after using the HP, its def. a bleed back problem. WHAT injection pump is on this machine.?? or is it a tier 4 w a hi pressure pump.?? If it has an overflow valve on it, THAT may be the culprit.?? Need more info..
Thanks guys here's the requested information. It's a John Deere 4045hf275, ser#Pe4045h468706 The injection pump is a Stanadyne DE electronic controlled pump, part # CD30928-UN-02FEB07. I have tried pumping the prime pump, doesn't seem to affect it. Seems now it only takes cracking one injector line to get it to start though. I really appreciate you guys advice.
The DE pump is a monster all its own.. IF u can get it started, does it pop, skip & smoke when u have it floored..just like its sucking air.?? There have been MANY UPDATES to that pump.. theres a set if springs in there that break.. & need to be replaced, if the problem is as described above.. {It will spew air out of the injectors}
The first few times I'd get it running yes it would run like you described, the last time it ran pretty smooth, through all throttle ranges. (I really thought I had it licked, silly me LOL)
Do you have any codes?
No codes that I know of. Not sure if this machine even has that capacity? Will have to read up on that.
If it has the DE10 pump and an engine controller then there will be a way to see codes.
Ok, I'll look into it. Problem is I have no manuals for this thing so having to internet search everything.
Theres a way to get the codes but i dont know the sequence.. Something like turn the key on & off 5x, stand on 1 leg & hop 3x.. u get the idea..