353 HST shuts off for no apparent reason

[tpcannon]

My 353 HST has just short of 500 hours on it. While operating it, the engine will just shut off suddenly. It will then start right back up. It would do this about every 3-4 hours, usually when I was working it clearing snow or grading our road. I suspected the seat safety switch. Now the problem has started happening every few minutes while operating the tractor, so the thing has become useless. Still suspecting the seat switch, I bypassed it. That isn't the problem, as the engine continues to die suddenly when it is at operating temperature.

I can hear the clack from the fuel solenoid when it happens. Sometimes, when the tractor is idling, the "Check" light will come on and go off, but in monitoring the dash while operating the tractor, there are no warning lights or indications that anything is wrong prior to hearing the fuel solenoid clack and the engine dying.

The only thing I've been able to find on the "Check" light is that it indicates an unsafe condition, but it doesn't outline what an unsafe condition is.

Any ideas?

 

[Tiptoo]

My 353 HST has just short of 500 hours on it. While operating it, the engine will just shut off suddenly. It will then start right back up. It would do this about every 3-4 hours, usually when I was working it clearing snow or grading our road. I suspected the seat safety switch. Now the problem has started happening every few minutes while operating the tractor, so the thing has become useless. Still suspecting the seat switch, I bypassed it. That isn't the problem, as the engine continues to die suddenly when it is at operating temperature.

I can hear the clack from the fuel solenoid when it happens. Sometimes, when the tractor is idling, the "Check" light will come on and go off, but in monitoring the dash while operating the tractor, there are no warning lights or indications that anything is wrong prior to hearing the fuel solenoid clack and the engine dying.

The only thing I've been able to find on the "Check" light is that it indicates an unsafe condition, but it doesn't outline what an unsafe condition is.

Any ideas?

Is this while the pto is running? Could be a short or disconnect in the seat switch...

If the pto is running and the brake is not engaged, the seat switch must be made. This applies to my tractor anyways... I don't know if yours is the same.

If it happens while not using the pto....then that would be tough to track down....

 

[thepumpguysc]

Does it shut off like its electrical.. someone turned off the key?? or does it spit & sputter like a fuel issue??
There is an electric sh/off solenoid screwed into the end of the inj. pump mount..
I don't know WHAT is causing your sh/down but the sol. is the end result.. they DO go bad at times..{weak coil}
Try unplugging it & cleaning the connectors & plugging it back in.. & while your in there, looked for any chaffed/shorted wires..
You COULD remove it & start the engine.. BUT.. you'd be bypassing your safety shut down capabilities..

 

[tpcannon]

Is this while the pto is running? Could be a short or disconnect in the seat switch...

If the pto is running and the brake is not engaged, the seat switch must be made. This applies to my tractor anyways... I don't know if yours is the same.

If it happens while not using the pto....then that would be tough to track down....

No, the PTO is in "Off". I have bypassed the seat switch because that was my first instinct. Maybe the fuel solenoid coil has gotten weak? Or there is a loose/corroded ground somewhere?

I'm seeing the "Check" light come on and go off at random, although I haven't seen any idiot lights or other dash indications when the fuel solenoid cuts out. Nonetheless, the "Check" light might be a clue. The manual says the "Check" light comes on if an unsafe condition is present, but it does not outline what an unsafe condition is. I only operate the tractor sober!

 

[tpcannon]

Does it shut off like its electrical.. someone turned off the key?? or does it spit & sputter like a fuel issue??
There is an electric sh/off solenoid screwed into the end of the inj. pump mount..
I don't know WHAT is causing your sh/down but the sol. is the end result.. they DO go bad at times..{weak coil}
Try unplugging it & cleaning the connectors & plugging it back in.. & while your in there, looked for any chaffed/shorted wires..
You COULD remove it & start the engine.. BUT.. you'd be bypassing your safety shut down capabilities..

Thanks for your reply!
When it shuts down, it is like the key has been turned off. I hear the clack of the fuel solenoid and the engine shuts off. Then it will start right up again. It may run for 30 seconds or it may run for 5 minutes before doing it again. Yesterday, it didn't start happening until the engine was up to full operating temperature and I was dragging road base with the box scraper.

I contacted the nearest dealer (100 miles away) yesterday morning and heard back from the service manager. He's helped me in the past. He suspects the oil pressure switch. He suggested that either it may be faulty or the oil viscosity is too light. I'll change the oil and make sure I have the summer oil in it. I may change the pressure switch on suspicion.

I know that there are more things that can cause the fuel solenoid to shut the fuel off to save the engine (and transmission?) So far, I know that a safety condition, like the driver out of the seat, is one of those conditions and the oil pressure switch is another. I wish I could find a full list of those safety conditions. It would be a troubleshooting checklist. I also wonder if there is a pressure switch for the transmission that does the same thing as the engine oil pressure switch?

I've looked over the wiring and the engine in general. It is very clean. I keep the tractor garaged and rarely operate it in dusty conditions.

I'll ask more questions of the service manager at the dealer and I'll post again when I've solved the problem or have more symptoms. It may be a while as I have other projects that are above the tractor on my "to do" list. By the way, I want to sing the praises of the service manager at Legacy Tractors in Ft Collins, Colorado. He's helped me in the past and is responding to my questions on this problem. it's great to know that you have a dealer that has your back.

 

[thepumpguysc]

The oil pr. switch is a weak spot in almost every engine & very inexpensive to replace.. about $25.00 in most cases..
It would def. be worth a try.. THAT & engine oil & filter change.. Good luck w/ your repair.

 

[TractorGuy]

Looks like you can download a workshop manual at Tym T353HST Manuals.

Was looking through and I don't see a simple list or method to read fault codes. On page 10-9 it has a short list of conditions that cause the engine to stop.

I would probably check and clean all the engine and frame grounds shown on pages 10-12 and 10-13. You might also replace all the fuses. I have seen fuse elements crack and not look blown but cause intermittent problems under load. These are simple cheap things to try on ANY problem that may be attributed to electrical faults.

I had been considering looking into a TYM since the prices are so reasonable but I have no use for a $25,000 yard ornament.

 

[darmstrong2319]

They all break if you use them. I’m thinking about one myself and may go for it but right now still researching. It seems tym has come a long way hope the op finds his problem without to much trouble

 

[Tiptoo]

They all break if you use them. I’m thinking about one myself and may go for it but right now still researching. It seems tym has come a long way hope the op finds his problem without to much trouble

I love my T234. $14200 was final price with loader. Check out my posts to see what it can do. I've been moving tons of dirt.

 

[tpcannon]

The oil pr. switch is a weak spot in almost every engine & very inexpensive to replace.. about $25.00 in most cases..
It would def. be worth a try.. THAT & engine oil & filter change.. Good luck w/ your repair.

Exactly my plan. The oil pressure sw is on order I have the filter and oil on hand. Just need time to do the job. Thanks for the support!

Oh, but the switch is $46 and after sales tax, shipping, and handling, nearly $70. I'm sure I could find it cheaper somewhere else, but this dealer has been great with their phone support, so I'm sticking with them.