Exhaust Mod on my 3725

[Branson Bob]

All good questions Slim. I think I was maybe jumping to conclusions. When I get back out there this weekend I'll be very methodical in checking everything including the air filter which I haven't cleaned out in a little while. I'll keep everyone updated on the progress and outcome.

Thanks Fellas.

After talking with you guys I was pretty sure I had jumped to conclusions about the DPF/DOC being the problem.

I started by pulling the air cleaner. It was quite dusty and it took a lot of compressed air from the air blow gun to clean it. I then went on to the inline water block fuel filter with the "clear" plastic housing.

I unthreaded it open and there was a lot of debris in it. Worse, there was a fair amount of water. Also there was some witish stuff on the ends of the pleated filter element where it meets the steel end caps. I couldn't tell if this is the adhesive they used in manufacture or some byproduct of a diesel and water reaction. I didn't have a backup element so I disassembled the filter and cleaned it by hand. I then dry fit it back together forming it into a cylinder and fitting the end caps on. There's a tension spring that sits at the bottom of the housing and seats the element back into an orifice. I will order backup air and fuel filters from Dave's this week.

After everything was put together I decided to take it down to the bottom of the property and back. I topped off the tank and after a fair bit of cranking she started up. It was about a 20 minute ride and I kept the rpms up, especially coming back uphill. It wasn't but 2 minutes into the ride that I knew I had fixed the problem.

I'll still probably gut the DPF/DOC but some other weekend. Thanks for all the help you guys.

 

[Branson Bob]

 

[K5lwq]

Glad you are back in business Bob!

 

[ptsg]

Wow! You have some strange things on your fuel Bob. :laughing:

I would check inside the tank as well. You have something floating around, causing the filter to get plugged.

 

[hank01]

We U.S. market Branson owners are very fortunate that at least for now, Branson is using an add-on emissions system that is a separate package they install on tractors sold in U.S. market only. What they've done is taken their "normal" tractor design, that they sell basically all over the world, and "added" this DOC system to it. This allows them to sell the same tractor models all over the world, but by checking an option box at the assembly line, this emissions system is added during the build...

I'm paraphrasing for emphasis, I don't really know that this is exactly what they do...

But functionally, and mechanically, what this means for us Branson owners here is, that emissions system is wholly stand alone, and doesn't tie into the engine controls in any way. They put the filter on in place where a muffler would go (in any other country they ship to), and they add a "data logger" to the top of the battery bracket. Then there are sensor wires that go from the data logger to the filter cannister, and a lead wire goes to the idiot light on the dash (and of course, power from tractor power to turn on the logger).

The only purpose the data logger serves, is to light the dash light if the exhaust gas pressure gets too far out of whack between the input side of the filter, and the exit side of the filter. That's all it does. It is an entirely "passive" system.

So as far as the actual engine operation goes, the engine has no idea whether or not a filter is in place, or a data logger is in place. They stand on their own as a separate system. Now if the filter gets plugged, (partially, or wholly) then the only impact on the engine is that it's trying to run through a plugged exhaust pipe (like a plugged muffler for example).

There is no other computer of any kind on the tractor.

What this means is that "YES", you can take the filter off, put a muffler in that filter's location (it is the same location that a muffler is installed in for the rest of Branson's world market), and the engine will run fine. The only reason you "need" to unplug the data logger, is so that the idiot light doesn't light up on the dash.

I have unplugged my data logger, and removed it from the tractor. Since doing that, my dash light never comes on.

Data Logger, at least on the 25 series (mine), it is located on the battery hold down bracket:

View attachment 653912

This retaining clip must be released, small screw driver in previous pic works well to press in tab, then rotate clip to right (in pic):

View attachment 653913

Then pull connector straight out the side of the logger. It was in there very solid, with a tight seal.

View attachment 653914

I was originally going to take the entire harness out, but it is woven into the main tractor harness, and I just didn't want to take the entire thing off, separate it out, and put the rest back. So I wrapped up the plug in plastic and tied it back to it's harness. The sensor wires are also tied back to the harness at the other end.

It's been this way for over a year now, and I haven't had any issues of any kind.

We U.S. market Branson owners are very fortunate that at least for now, Branson is using an add-on emissions system that is a separate package they install on tractors sold in U.S. market only. What they've done is taken their "normal" tractor design, that they sell basically all over the world, and "added" this DOC system to it. This allows them to sell the same tractor models all over the world, but by checking an option box at the assembly line, this emissions system is added during the build...

I'm paraphrasing for emphasis, I don't really know that this is exactly what they do...

But functionally, and mechanically, what this means for us Branson owners here is, that emissions system is wholly stand alone, and doesn't tie into the engine controls in any way. They put the filter on in place where a muffler would go (in any other country they ship to), and they add a "data logger" to the top of the battery bracket. Then there are sensor wires that go from the data logger to the filter cannister, and a lead wire goes to the idiot light on the dash (and of course, power from tractor power to turn on the logger).

The only purpose the data logger serves, is to light the dash light if the exhaust gas pressure gets too far out of whack between the input side of the filter, and the exit side of the filter. That's all it does. It is an entirely "passive" system.

So as far as the actual engine operation goes, the engine has no idea whether or not a filter is in place, or a data logger is in place. They stand on their own as a separate system. Now if the filter gets plugged, (partially, or wholly) then the only impact on the engine is that it's trying to run through a plugged exhaust pipe (like a plugged muffler for example).

There is no other computer of any kind on the tractor.

What this means is that "YES", you can take the filter off, put a muffler in that filter's location (it is the same location that a muffler is installed in for the rest of Branson's world market), and the engine will run fine. The only reason you "need" to unplug the data logger, is so that the idiot light doesn't light up on the dash.

I have unplugged my data logger, and removed it from the tractor. Since doing that, my dash light never comes on.

Data Logger, at least on the 25 series (mine), it is located on the battery hold down bracket:

View attachment 653912

This retaining clip must be released, small screw driver in previous pic works well to press in tab, then rotate clip to right (in pic):

View attachment 653913

Then pull connector straight out the side of the logger. It was in there very solid, with a tight seal.

View attachment 653914

I was originally going to take the entire harness out, but it is woven into the main tractor harness, and I just didn't want to take the entire thing off, separate it out, and put the rest back. So I wrapped up the plug in plastic and tied it back to it's harness. The sensor wires are also tied back to the harness at the other end.

It's been this way for over a year now, and I haven't had any issues of any kind.

Did unplugging the data logger affect any of the other dash instrumentation other than the idiot light?

 

[Slowpoke Slim]

Not on mine.

If Branson has made changes to the wiring harness on the new models, that would be news to me.

You should start a new thread and get "everyone" involved here so we can help figure out what's going on. If they did make changes, we need to get that information out to the new Branson owners.

 

[hank01]

Not on mine.

If Branson has made changes to the wiring harness on the new models, that would be news to me.

You should start a new thread and get "everyone" involved here so we can help figure out what's going on. If they did make changes, we need to get that information out to the new Branson owners.

I have not yet started the modification on the tractor but I have issues with the DPF plugging when the tractor is not operated at a high rpm. I am not particularly fond of constantly running the tractor hard to keep the DPF burned off. Uses a lot more fuel and seems to be operationally more difficult when using the tractor in confined spaces. Your post gives a good explanation of how the mod will work. I just wanted to know if the unplugging of the data logger affected any of the other instrumentation. I will post the results one the mod is completed.

 

[Slowpoke Slim]

Ok, cool.

I was afraid there were changes made in the way the new models were wired, and that you were having problems after the mod was finished.

Good luck on your mod, I know I'm pretty happy I did mine.

 

[FastEddieR]

Slowpoke, I was just on the Stanley Muffler site checking it out. I noticed the IH-10 has the same measurements as the IH-4. Only difference is that it's listed as good for both gas and diesel and priced $2 more at Tractor Supply ($39.99 vs $37.99). Why did you choose the 4 over the 10? Availability? And does anyone know the actual difference between gas and diesel mufflers? I would expect a diesel muffler has larger holes to compensate for more particulate matter in diesel exhaust, but can't really see that there would be that much difference actually.

 

[ericm979]

The diesel muffler would be tuned to suppress sound at a lower rpm since diesels run slower (though old gas tractors didn't turn much faster, so maybe not). And maybe for more flow, not because of the PM but because a diesel has no throttle and is always pumping the maximum amount of air.