Oil & Fuel jd 790 will not start

[gary messenger]

Having problem with tractor starting.Turns over but not start.I am sure its a fuel problem.Installed new fuel filter.Guel pump was not clicking.found that fuse was blown.Put in 3 new fuses all blew.Put in a 20 amp instead of 5 amp.Pump now clicks but would not start.I them bled the system.Am getting good fuel to injector pump,but nothing out of the pump
Any help would be appreciated.

 

[sisupower]

Fuel tank clean? Free of rust and debris? Is it a metal tank?

 

[gary messenger]

Metal tank,clean of rust and debris.Good fuel glow to injector pump.No glow out of pump

 

[sisupower]

I've had issues in past with the injection pump jelling up or getting something lodged in it. Either that or it's toast and needs a rebuild.

 

[sisupower]

3 months ago I got 5 790 tractors in shop that needed work. Big jobs. Mostly front axle stuff. But they show in groups. I won't see one probably till same time next yr lol. It's funny how it works

 

[gary messenger]

A bad pump is what i am thinking also.Any idea why fuses keep blowing?Could the solenoid have any connect tp the problem.

 

[sisupower]

Um not sure I'd have to look at the schematic and see. I can look Monday when I'm back in shop

 

[Spanner]

Proof-reading your posts would be a good idea. "Guel" & "Glow".

Electric fuel pump is pumping now with the 20A fuse and you get fuel at the IP inlet. Try a 10A fuse. I think 20 is too big.
No fuel out to engine when cranking.

Before condemning the entire FIP -

I would suspect the Solenoid. Check other fuses to ensure you have power to the solenoid "Pull" circuit when cranking.

Use the "Search'' function on here. Numerous threads describe this issue already.

 

[Phillip w]

Here is my thought. How has the tractor been running? Most of the time, but not always the injection pump will" start talking to you" before it gives up . The engine will kind of surge at times, or it can be hesitant when you put the throttle to it. It you under a load or hard pull, your "power my seem anemic. I take a hard look at the fuel solenoid. The fuel solenoid went out on my dad's little John Deere. There was no getting the tractor going without it. I think it costed him about 150 dollars but it is a pain to replace.(need really small hands)

 

[kuboman]

Are you getting smoke out the exhaust when you are cranking? If not then it will be the fuel solenoid. If you are then check glow plugs.

 

[thepumpguysc]

Just remove the solenoid from the pump.. should be 2, 10mm bolts holding it on.. THEN proceed w/ your pumping diagnosis..
Loosen the lines AT THE INJECTORS, ALL OF THEM..
Crank the engine.. got fuel squirting out the lines?? YES.. the problem was the solenoid or electricals going to it..
IF NO.. reach in where the sol. goes & feel for the control rack or something to push or pull on.. cuz that's all the solenoid does..
SEE/FEEL if you can get anything to move.. if so.. crank the engine again.. GOT FUEL??

 

[gary messenger]

I had 2 blown fuses one for fuel pump and one to fuel shutoff.Replaced still wont start.removed and tested fuel shutoff solonoid.It seems to be working.Other than injector pump,what else can it be

 

[Spanner]

Let's go back to this "Fuse" thing...

You had a fuse blow 3 times and you eventually replaced it with a 20A which seems to 'work' but the circuit is low amps and as 'K7LN' advises only rates a 5A.

Now you say you have 2 different fuses blow??

And you "tested fuel shutoff solonoid" (sic) and it "seems to be working".

Can you detail just exactly what & how you tested to reach this conclusion?

Have you re-checked these 'two' fuses again?

Did you 'Search' the forum as suggested?

 

[gary messenger]

Sorry for the confusion.Originally i found 1 blown fuse,that wS to the fuel pump.Thats the one that blew 3 times and i put in the 20 (I am goinh to put right fuse back in).I later found the second fuse blown,it was to the feel shutoff solonoid.Replace that.Still wont start.Pulled the solonoid and ran wire from a battery to the pig tail.plunger pulled in stayed till i removed wire. It is leaking black oil.
was thing about taking to dealer and have the check it.
I really appreciate your help

 

[gary messenger]

Sorry for the confusion.Originally i found 1 blown fuse,that wS to the fuel pump.Thats the one that blew 3 times and i put in the 20 (I am goinh to put right fuse back in).I later found the second fuse blown,it was to the feel shutoff solonoid.Replace that.Still wont start.Pulled the solonoid and ran wire from a battery to the pig tail.plunger pulled in stayed till i removed wire. It is leaking black oil.
was thing about taking to dealer and have the check it.
I really appreciate your help

Is there supposed to be oil in the solonoid?

 

[kuboman]

Is there supposed to be oil in the solonoid?

I don't believe so.

 

[thepumpguysc]

The sol. is "cooled" by splash oil from the pumps cambox.. excess oil accumulates in it & keeps it from functioning.. factor built-in problem..

 

[Spanner]

Sorry for the confusion.Originally i found 1 blown fuse,that wS to the fuel pump.Thats the one that blew 3 times and i put in the 20 (I am goinh to put right fuse back in).I later found the second fuse blown,it was to the feel shutoff solonoid.Replace that.Still wont start.Pulled the solonoid and ran wire from a battery to the pig tail.plunger pulled in stayed till i removed wire. It is leaking black oil.
was thing about taking to dealer and have the check it.
I really appreciate your help

How many terminals in your solenoids 'Pigtail'?

There are two (2) circuits in the Fuel Solenoid. You tested the 'Pull' circuit. It "Pulled".

There is also the "Hold" circuit. There are literally hundreds of posts on here detailing 'Pull' & 'Hold'.

Reads like oil has got past the seal on the plunger pin. You can press the plunger with your finger a few times and purge the oil out as a temporary solution.

 

[sisupower]

So check the resistance on the terminals in connector. Should be 3. See pic.
As stated in Tech manual some numbers don’t match so this is what you need to see if your solenoid is good.
Fuel shutoff solenoid—
C to D ..........0.5 ohms
C to E ..........23.5 ohms
D to E ..........23.5 ohms

See what you have.

 

[Industrial Toys]

I used to have a 770, basically the same machine.

If you had a lower fuse rating that worked and now need a heavier fuse, to me, that is OBVIOUSLY your problem. Maybe shorted coils in the fuel pump.

Putting in larger fuses is a good way to start a fire!