Branson 4215R - Confirm Diagnosis

[Certified_GSD]

Hello there,


It's my job to figure out how to get this Branson running again. As I drive a diesel vehicle, I know how important it is to NOT pour gasoline in the tank. Someone else didn't think so.

Fuel tank, fuel lines, and fuel pump has been cleaned and cleared. Both fuel pumps are working and pumping diesel through the lines.

However, I can't get the tractor to start. After I let the plugs do their thing, the engine will crank and sputter and fire once or twice and then it will die and continuing to crank bears no fruit. If I cycle the plugs and pumps again, it will fire once and then die. It usually runs between about 500-1000 RPM before stopping. A few times I can hear the piston slapping but it's not every time the engine is cranked.

I am almost certain it's the injectors but I'm not quite sure how they can inject fuel for one puff and then stop. What's the best way to go about testing the injectors? I'm no expert but I'm fairly certain these are mechanical injectors as I see no electronics; can I simply unplug each of them and crank the engine and see if they're spraying correctly?

Is there something I am missing? It has to be a fuel issue not feeding correctly into the engine, although I am worried that the occurrence of the piston slap may be sign of more trouble inside the combustion chamber.


Any ideas, even simple ones, would be appreciated. Maybe it's a simple thing I am overlooking. Thanks!

 

[ericm979]

Did you bleed the injector lines to get any air out? Could there be residual gas or solvents in the system?

 

[oldnslo]

Was the tractor run after filled with gas? If yes for how long? Typically a small amount 10 percent or less of gas mixed with diesel won’t hurt a diesel if higher percentage and ran for time it could have done some engine damage.

the fact that it puffs and tries does point towards air in system so like Eric suggest bleed everything again

 

[Certified_GSD]

Did you bleed the injector lines to get any air out? Could there be residual gas or solvents in the system?

I'm sure all of the fuel running through is diesel. I've bled the HPFP so that it's pumping diesel, and I've removed the line from the HPFP to confirm that all four lines are getting fuel.

I'm not sure if I've bled the air through the injector line but I'm not sure that's the issue as it does fire very briefly. Space is tight, tomorrow I will crack open the fuel line at the opposite end of the HPFP and make sure fuel comes out the other end. Might be tricky because I have to deal with the fuel return line.

Was the tractor run after filled with gas? If yes for how long? Typically a small amount 10 percent or less of gas mixed with diesel won’t hurt a diesel if higher percentage and ran for time it could have done some engine damage.

the fact that it puffs and tries does point towards air in system so like Eric suggest bleed everything again

It was run until it sputtered and stopped. It's primarily why I think the injectors are bad as I know they're generally the most delicate of the fuel injection system that rely on the diesel lubrication.

I'm stumped at the fact that it puffs and fires and I can hear briefly the telltale diesel "knock" so I know there's some combustion before it cuts out. If I keep trying to crank the engine, it will not fire at all and I can't check if there's fuel in the exhaust because of the DPF. If it didn't fire at all or had really low power I'd be having a different conversation. It's like the injectors fire a a handful of times and then stop, but they're mechanical so either they're working or they're not, right?


I'm going to charge the battery overnight, on the chance that maybe it's just not quite cranking fast enough to get all four cylinders going, but then I'd expect the one or two good cylinders to carry things along until the diesel goes "boom" in the others. I don't want to use ether as it's not my tractor and I don't want to cause more damage to pistons that have seen gasoline. Is it possible the HPFP was damaged and can provide a small amount of diesel to start but not enough to keep things going?

 

[CoyPatton]

Your goal in bleeding fuel lines is not to see fuel, but to not see air. Bleed until a steady stream of fuel, no interruption of fuel by air.

 

[oldnslo]

Certified
You stated cleaned fuel pump. Did you remove and or dismantle the fuel pump to clean? If yes are you sure the pump is timed correctly when reinstalling? If not timed it may sputter and then quit.

 

[Certified_GSD]

Your goal in bleeding fuel lines is not to see fuel, but to not see air. Bleed until a steady stream of fuel, no interruption of fuel by air.

Yeah, I had a thought: if there's air in the injectors, they're not going to fire and clear the air, therefore the air stays stuck. So I'm thinking there's only enough fuel for one or two cylinders to fire but not enough to keep things going. Been busy so this had to be put off.

Certified
You stated cleaned fuel pump. Did you remove and or dismantle the fuel pump to clean? If yes are you sure the pump is timed correctly when reinstalling? If not timed it may sputter and then quit.

Nah, I just ran cycles of the fuel pump with some PowerClean in the fuel bowl until only diesel came out. Timing the fuel pump is out of my expertise, that'd be something I'd be paying someone else to do.



Forecast says rain tomorrow so that should give me the free time to put a pause on farm work and get this tractor running. Thanks for the suggestions everyone, I'll update what happens tomorrow.

 

[ericm979]

If there's air in the lines cylinders may fire sometimes when enough diesel gets to them even though it's not enough to get the engine running. Follow the manual's procedure to bleed the fuel filter and then to bleed the lines. If the problem is actually the injectors this won't make them worse and it'll be practice for after you replace them.