John Deere 755 won't start!

BLC755 · Mar 17, 2016

755 had been getting harder an harder to start temp no difference ! Crank an crank whit gray smoke unburned fuel new glow plugs still no start new injector lines and injectors bled all the way to injectors now not smoking!!! Somebody on here said glow plug relay module just got a new one today still no start !! About 1000 hours on engine getting fuel up to injectors !!!! Still cheaper than taking to dealer had this tractor 20 years with no problem till now!!! Anybody have any ideas!!!!

yankeerider · Mar 18, 2016

You need air and fuel to start. What is condition of air filter?

BLC755 · Mar 18, 2016

Hey thanks for reply you're the only one that's answered! Right now don't have air cleaner even on it still won't start ! Have it in shop! Had it off to bleed injector lines!!! It about has me ready to pull what hair I have left out!!! Bob

jd4310man · Mar 19, 2016

Make sure your fuel system is clean. The tanks on these have no drain and they will collect alot of dirt and water at the bottom of it. I had to remove mine as it had dirt and water in it. Is the tractor smoking at all when you crank it over? If its smoking, your getting fuel so its likely a glow plug issue.

Ed of all trades · Mar 20, 2016

You saying its not "smoking" says it is not getting fuel. Bleed it at the injectors and ge it smoking again. Ed

BLC755 · Mar 21, 2016

Thanks for your replies!!! I have bled lines all the way to injectors till bubbles stopped ! Fuel pump is shooting out diesel 4 or5 inches when I bled at filter and injection pump!!! No smoke!!!! I'm baffled ???? Bob

BLC755 · Mar 26, 2016

Thanks 4310 & Ed I bled & bled lines still no smoke no start! Would it still smoke with low compression ! I'm thinking it. Needs new rings or possibly more! The Bob

Jerry/MT · Mar 26, 2016

BLC755 said:
755 had been getting harder an harder to start temp no difference ! Crank an crank whit gray smoke unburned fuel new glow plugs still no start new injector lines and injectors bled all the way to injectors now not smoking!!! Somebody on here said glow plug relay module just got a new one today still no start !! About 1000 hours on engine getting fuel up to injectors !!!! Still cheaper than taking to dealer had this tractor 20 years with no problem till now!!! Anybody have any ideas!!!!

You need four things to start a diesel: fuel. air, compression and a good starter motor/battery. In cold weather there is a fifth requirement, a starting aid ( glow plugs,Thermostart, block heater).

Just because you see fuel coming from the injectors doesn't mean that you have adequate flow to continue starting and operating. If the fuel delivery is restricted , inadequate fuel flow will not allow the engine to start. The tank strainer can be clocked, fuel lines might be pinched or otherwise damaged, the fuel filter may be partially clogged, filter maybe frozen due to water in fuel, summer fuel maybe waxy due to low ambient temperatures. lift pump may be damaged (if you have one), the air filter may be clogged, fuel cutoff lever not opening etc, etc. The last thing to suspected the injector pump itself, but if everything checks out (in cold weather your starting aids are working, your batter & starter are strong) and you have adequate compression, the pump can't be ruled out. They are hydromechanical devices and they do break.