Deere 3020 Diesel getting air in fuel

TravRed

New User
I have had a 63' 3020 Diesel and it has run great for a year. Just recently it starts to die after 6 or 7 minutes. It has the clear square fuel filter and starts out completely full. Starts right up and runs. after a few minutes you can see air bubbles forming after about 5 min it gets frothy and starts to sputter. I can let it sit for 2 min and it fills back up and runs great for 5 min again. I have tried bleeding the lines over and over at the fuel pump but no help. I don't see any leaks in the line or fittings. Before I just start replacing lines and fittings can anyone tell me a good place to start looking for where air is getting in. I have a full tank of diesel.
 
It shouldn't be getting air from a bad fuel pump IF the tank is full. And fuel would typically be running out of the weep hole on the pump and/or into the crankcase.

Is it POSSIBLE a chunk of debris is getting sucked against the fuel outlet port in the tank (or in the valve or elbow) that partially allows flow when it's sitting without suction from the fuelpump?

(Safely) with a catch can at hand, engine stopped and cool, loosen the fuel line coming into the pump and note if there's a good stream of fuel, or just a dribble.
 
I disconnected at the fuelpump and its a steady drip drip drip. No flow. I disconnected at the fuel filter going to the fuel pump and its the same drip drip drip. No flow. I disconnected the line coming from the tank to the fuel filter and same drip drip drip. No Flow.
So I'm assuming that line between the tank and the filter is the cause.
 
"I disconnected the line coming from the tank to the fuel filter and same drip drip drip."

Just to clarify here, so yours has a fuel filter in the line from the bottom of the fuel tank to the lift pump at the lower right side of the engine, near the front of the block?
 
Correction. I apparently skipped the fuel pump. The fuel goes
Tank -> fuel pump -> fuel filter -> injection pump (i think it's called). THe square clear fuel filter is on the left side of the engine, the fuel pump is on the right side towards the front and the injector pump is on the right side towards the rear. I disconnected the line coming off the bottom of the tank going to the fuel pump and still no flow. With a full tank of gas I would think it would be a stream? I can't see a way to get to where the line attaches to the bottom of the tank. Its sandwiched between the tank and the front end. Also I have a front end loader so that blocks my view. I'm guessing I need to siphon out the diesel of the tank and pull the tank up to get to the fuel line. I can see how its attached with band clamps. If I have to remove the tank I might as well clean it out and start working my way back.
 
With the fuel filler cap off, blow a shot of compressed air backwards through the fuel line ahead of the lift pump.

That may clear debris for a little while or for YEARS.

A friend of mine has a 4630 that we've done that to twice in 20 years.

Of course, removing the tank and cleaning it properly would be even better!
 
Haha. Went back out there and started contemplating pulling the tank when my 80 gallon shop compressor kicked on. Figured why not. Gave it 120psi and ..... fixed!
Plenty of flow now. Runs good.
 
Now check the bottom of the tank there should be a petcock that you can open and drain some of the crap and water out of the tank
 
Well looks like his line was clogged. But a bad check
valve in the fuel pump causes foaming from fuel pumping
back and forth.
 
(quoted from post at 15:26:47 03/10/18) Haha. Went back out there and started contemplating pulling the tank when my 80 gallon shop compressor kicked on. Figured why not. Gave it 120psi and ..... fixed!
Plenty of flow now. Runs good.

Ha Ha, I typically go "above and beyond" to fix things right.

But sometimes a "MacGuyver" fix ain't too bad either!
 

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