4120 engine surging and then stalling

[tinsnip]

I'm re-awakening this thread since the problem persists. I thought I had it licked after replacing the fuel filter (twice!). I've had it running straight for over 2 hours at a time but just today, it started all over again.

The consensus from the guys hanging around the Dealer's counter is that there's some dirt in the fuel tank that needs to be cleaned out. Does anyone know where I can find an exploded view diagram of the fuel tank and/or directions on how to best drain and clean the fuel tank?

Also, what, if anything, exists in the fuel line between the tank and the filter? Is there another mechanism I might be overlooking?

Just to be clear, the fuel is fresh and the filter is brand new as of 1 hour ago. I'm not seeing any kind of message on the readout except "default" and when it runs, it purrs. And then suddenly it will change tone, blow black smoke and the engine pulses. Throttling down all the way uses causes it to stall. If it sits for 30 minutes or so, it will restart and run for a completely unpredictable amount of time.

Thanks for your help.

Tim

 

[beenthere]

You can view the schematic of the tank and associated parts on jdparts.com (free registration). Just type in the model # and then find it on the list... click and then go to alphabetical listing under F for fuel tank. You will see the lines there.
As to cleaning... various ways but I'd disconnect one of the outlet lines at the most bottom point to drain.. then rinse well.
Sounds like debris in the tank. Maybe even algae.

 

[Tx Jim]

tinsnip
Did you try operating with fuel cap loose/absent as dusty3030 suggested?

 

[tinsnip]

Thanks for your replies. I'll check the schematic and attempt the drain and clean tomorrow. And yup, I tried loosening the cap several times and it made no difference. Thanks again.

 

[tinsnip]

Just to beat this to total death... I'm still struggling for a solution to the original problem. I've completely drained the fuel from the tank, replaced the filter, then filled the fuel with diesel purchased at a different location and used a brand new fuel can (just to eliminate the possibility of contaminated stuff). All other fluids and filters are new and/or in top notch condition. But once again, at about the 1 and 1/2 hour mark, the engine began to stumble, then surge, with a big loss of power. I did notice a clicking sound but am not enough of a diesel-head to know what's causing it. Is there an electrical solenoid somewhere that might be failing or overheating?

I'm pretty much at the limit of my paltry mechanical abilities and about ready to trailer it into the JD dealer so they can suss it out. Paying them to come out here is out of the question (big bucks!).

 

[arlen4720]

There is a fuel solenoid of course. That could be dropping out.

 

[tinsnip]

I replaced that last year. Is it possible that it's bad again or was installed improperly? Could the length of time be influencing its function? I t runs like new right up until the point it dies, which is almost always at around 1.5 hours. Heat? Thanks for your interest and ideas.

 

[tinsnip]

Just to close this out. Ended up taking it in to the dealer for service. The mechanic drained the fuel into a bucket and said he saw orange mixed in. He thinks there was gas contaminating the diesel. He said that the gas makes the fuel burn hotter and that after awhile, the injectors would heat up and begin to fail. Hence the loss of power, smoking, and surging.

I had drained it myself but into narrow-mouth cans and never looked at the fuel. Since he had blown out all the lines and probably did a better job of draining it completely, I think he managed to remove any traces of the gas that was still trapped in the system. It's now back to running fine and I'm hopeful that this episode is over.

I had been buying my off-road diesel at the small general store here in town. They have two diesel pumps, one for clean diesel and one for off-road diesel. The ORD is one side of a two-hose pump. One of those old-style gas pumps with a hose/handle on either side. If I was to guess, I'd say that the wholesaler accidentally started putting gas into the wrong in-ground tank. But that's pure speculation. Regardless, I'll be buying my diesel elsewhere.

Fingers crossed that this episode is over and I consider it a valuable lesson learned.

Tim

 

[beenthere]

I take from your experience that I will stay away from off-road and continue to buy diesel from the pump that the truckers use. The few penny's saved with the off-road coming from a seldom-used pump/tank can end up being costly. Thanks for the "lesson learned".

 

[arlen4720]

Just to close this out. Ended up taking it in to the dealer for service. The mechanic drained the fuel into a bucket and said he saw orange mixed in. He thinks there was gas contaminating the diesel. He said that the gas makes the fuel burn hotter and that after awhile, the injectors would heat up and begin to fail. Hence the loss of power, smoking, and surging.

I had drained it myself but into narrow-mouth cans and never looked at the fuel. Since he had blown out all the lines and probably did a better job of draining it completely, I think he managed to remove any traces of the gas that was still trapped in the system. It's now back to running fine and I'm hopeful that this episode is over.

I had been buying my off-road diesel at the small general store here in town. They have two diesel pumps, one for clean diesel and one for off-road diesel. The ORD is one side of a two-hose pump. One of those old-style gas pumps with a hose/handle on either side. If I was to guess, I'd say that the wholesaler accidentally started putting gas into the wrong in-ground tank. But that's pure speculation. Regardless, I'll be buying my diesel elsewhere.

Fingers crossed that this episode is over and I consider it a valuable lesson learned.

Tim

Glad you got it figured out, and you're lucky it didn't tear up the unitary injector pumps. Maybe the dealer serviced them?