Strange BX Starting Issue

[drssg]

I did a search and didn't find anything quite like this issue. I have a BX2350 with about 1200 hours on it, and I bought it new.

I started it today, and it fired right up, but the RPMs raced to about 3500, even though I moved the throttle all the way down. This continued for about 15 seconds as it belched thick black smoke, and then it died. I tried to restart, and it would turn over, but it wouldn't start. I let it sit for about 15 minutes, tried again, and it ran fine. It has behaved similarly for the last three days, but each day gets worse.

I don't know if it's related, but the temps have been single digits recently. In the winter time, I use this tractor daily, but not for an extended period. I just haul manure out of the barn. I let it run for a while yesterday at about 2800 RPM. I was thinking that maybe it just needed more use, but that didn't help today.

Any ideas?

 

[Mowbizz]

Not sure about the "revving" thing but usually the fuel filters are the cause of stuttering and stalling in cold weather. Diesel gelling and freezing will block them (filters) if the diesel fuel has water in it.

Have you changed the filters on the BX lately? Also check the air filter for blockage of any sort...sorry, that's all I can suggest because I have had the stalling out on mine this winter due to gelling/freezing fuel.

 

[sdk131]

I am not a mechanic....but revving on its own is not a good thing. I seriously recommend that you get it to a mechanic for an inspection asap. Stalling and sputtering are happening to a lot now (including me) due to gelling fuel which causes fuel starvation at the engine. What you have going on is the opposite. It seems like fuel or lube oil is making its way into the cylinders when you have it parked...then it is revving uncontrollably when you get it started. You're lucky you've got is stopped and then able to restart. This condition often ends in catastrophic damage when the owner is unable to stop the engine and it runs up to high speeds until something breaks. Just google "runaway diesel." If I were you I would stop trying to run it all all until the issue has been identified.

 

[drssg]

Thanks for the feedback. All the filters were replaced last summer, so those should be good.

sdk131, that sounds scary and quite plausible. The symptoms match and it kind of matches the recent history with this tractor. I spent a bunch of money last year to fix transmission/hydraulic leaks and the front axle seals also needed replacing. I currently have another rear axle leak and a hydraulic leak under the steering wheel. Neither of these look like they would affect the engine, but there does seem to be a general tendency for oil going where it's not supposed to be. I could definitely picture oil somehow leaking into the cylinders as it sits.

I think I'll leave it parked until I can get it into the shop. I had never heard the term "runaway diesel," and I appreciate the heads up. It's kind of a pain to not have the BX for daily use, but "catastrophic damage" sounds worse.

 

[sdk131]

Right...hope I am wrong...but better to be safe than sorry.

 

[drssg]

I have a bit of an update, for anyone that's interested. After a month, the snow was finally gone from my driveway, so I was ready to take the tractor into the shop. Getting it loaded on the flatbed without turning it on was a treat. I learned that I have NO steering when the engine is off. I was expecting it to just be more difficult to steer, but it turns out that the steering wheel just spins without effect when the engine is off.

I got to the shop, told them the situation, and a couple of mechanics came out to the trailer and told me to start it up. I was a bit nervous, because they really didn't look like they were poised to leap into action to somehow shut off the tractor, if needed. I prepared for the worst, started it up for the first time in a month, and it purred like a kitten.

So they didn't sound too confident that they could make a clear diagnosis, but I had other work to be done on it, and they had a backlog of other tractors ahead of me.

I received a call yesterday, it did the same revving issue for them, and they said it was the fuel injector sticking. They suggested replacing the fuel injector, which is a lot of money, but hopefully that will take care of it.

 

[Rod in Forfar]

I did a search and didn't find anything quite like this issue. I have a BX2350 with about 1200 hours on it, and I bought it new.

"I started it today, and it fired right up, but the RPMs raced to about 3500, even though I moved the throttle all the way down."

You haven't mentioned if you have any fuel conditioner in the tank. My 35 hp TAFE acted like this when its fuel system froze up for the first time this winter. After the application of diesel winter conditioner I noticed that the volatile components in the additive made the engine rev up considerably more than usual at start.

Something to check as well is the air cleaner for ice.

Sounds as though the tractor would appreciate some time in a heated garage to eliminate ice as a potential issue.

 

[drssg]

You haven't mentioned if you have any fuel conditioner in the tank. My 35 hp TAFE acted like this when its fuel system froze up for the first time this winter. After the application of diesel winter conditioner I noticed that the volatile components in the additive made the engine rev up considerably more than usual at start.

Something to check as well is the air cleaner for ice.

Sounds as though the tractor would appreciate some time in a heated garage to eliminate ice as a potential issue.

In my case, I wasn't using fuel conditioner, and the shop claimed they repeated the behavior when it was considerably warmer outside. I'm paying a bunch of money to have a new fuel injector installed, so hopefully that was the problem.

I agree that winter is hard on all of us, and a heated garage would be nice. But I don't own one, so the horses AND the tractors will have to make do without one.

 

[pap71]

Is the dealer telling you that only one injector is sticking? I am trying to understand how one injector can cause this. I am not a diesel mechanic but worked for a GM and Honda dealer ship for 35 plus years. I have had many cars with bad injectors but the engines never reved like that. I know this is two different animals but am trying to understand how a stuck injector can cause this.

 

[whis]

may be talking about the fuel pump, one injector shouldn't be real expensive

 

[pap71]

may be talking about the fuel pump, one injector shouldn't be real expensive

Fuel pump wouldn't cost much either. Maybe the injector pump?

 

[tjkubota93]

Is the dealer telling you that only one injector is sticking? I am trying to understand how one injector can cause this. I am not a diesel mechanic but worked for a GM and Honda dealer ship for 35 plus years. I have had many cars with bad injectors but the engines never reved like that. I know this is two different animals but am trying to understand how a stuck injector can cause this.

A gas engine's speed is controlled by limiting air with the throttle.

A diesel engine's speed is controlled by limiting fuel, it can get as much air as it wants.

So-any extra fuel can result in uncontrolled engine speed. I have seen more than one do it. The most memorable was one that was grossly overfilled with oil.

Thats the basics. After that you gotta look at interwebs or pay your local community college for some learnin.

That engine has an injector pump and poppets. A stuck poppet would not result in a runaway. Neither would a fuel pump. An injector pump could. They are high $ too.

 

[drssg]

Thanks for the overview, tjbeck93. The tractor's still in the shop, so I'm just going from memory and a phone call with them. I'll confirm the actual parts that were replaced when I get the paperwork.

 

[whis]

I can't spell or type very well that's why I said fuel pump

 

[l0ad3dr3v0lv3r]

Hi all. I know this thread is pretty old, but I have been having the EXACT same issue here in Ontario were we're sitting at -12 right now. Tractor would fire up, rev extremely high and stay there while black smoke shot out the exhaust. After several minutes the RPM's would start dropping, even if I gave it more throttle, right to the point of sputtering and then dead, and then nothing would get it to turn over again. This morning I added some diesel fuel additive and it seems to have at least temporarily fixed the problem. I'm hoping that was it as that was a cheap fix. I was hoping drssg would let us know what was finally fixed on his tractor and if that resolved the issue?

 

[drssg]

I reread this thread, and I noticed that my final post was that I would post the exact part that was replaced, when I got the tractor back from the shop, which I never did. Sorry.

I found the paperwork, and the part description just says ASSY PUMP, but the comments described it as an injection pump. The part number is 16006-51012. Just that part cost $830, seven years ago.

That fixed the problem, but a year later I had another fuel issue in that it would crank, but wouldn't start. They initially suggested replacing the same pump again. When I reminded them that the pump was only a year old, they suggested that they could ship the pump out and have it serviced. That was $369.

Since then, the tractor has run well, with daily use. I never did try using fuel additives or cleaners. I would say that you may or may not have resolved your issue. My original issue was sporadic. Good luck.