TC 40D hard starting

[brianb33]

I had fuel starvation issues and ultimately drained and cleaned fuel tank, replaced fuel lines, cleaned fuel bowl top assembly, and replaced the fuel filter. That solved about 80% of the problem. It still can be slow to start at first, and rpms will not increase for a few minutes until the engine warms up even with the throttle full open. It seems to want to bog down more under a load. My biggest issue now is it tends to stall when I stop and reduce throttle to minimum, especially if it is still in gear. After that it is very difficult to start, even tried bleeding fuel line with no luck. After it sits overnight it will start up as usual. When it happened today I replaced the fuel filter and I had to loosen the ring to allow air to escape so the fuel would flow and fill the bowl. I seemed to remember in the past if I cranked the engine the fuel filter would fill rapidly but it didn't today. About the only thing I haven't done is clean/replace the fuel pump. Can that be the problem? Is it possible to disassemble the fuel pump and clean it out?

 

[jinman]

Brian, the fuel pump is after the filter and before the injector pump. The pump actually pulls a vacuum on the fuel filter. It does not send pressure to it. That's why you must have a good seal on the fuel filter gasket so air is not sucked in and mixed with the fuel to the injector pump. The best way I have found to fill the filter bowl is just to pull the injector return vent hose on top of the filter. Fuel from the tank comes from the hose on the left. If you have plenty of fuel in your tank, that should not take long to fill the filter until fuel runs out the top vent hose. If it does, you still have a clog somewhere in your line from the tank. Using your pump to try and fill the filter bowl is a sure way to get air into your injector pump.

 

[brianb33]

Brian, the fuel pump is after the filter and before the injector pump. The pump actually pulls a vacuum on the fuel filter. It does not send pressure to it. That's why you must have a good seal on the fuel filter gasket so air is not sucked in and mixed with the fuel to the injector pump. The best way I have found to fill the filter bowl is just to pull the injector return vent hose on top of the filter. Fuel from the tank comes from the hose on the left. If you have plenty of fuel in your tank, that should not take long to fill the filter until fuel runs out the top vent hose. If it does, you still have a clog somewhere in your line from the tank. Using your pump to try and fill the filter bowl is a sure way to get air into your injector pump.

I was concerned about that so I didn't crank it for very long. I like your suggestion to bleed the air out of the filter bowl, unscrewing the ring was pretty messy, but it did fill quickly. I am still trying to figure out my intermittent fuel starvation issues (if that's what it is). Can the fuel pump be gummed up? That is about the only point in the system that has not been cleaned/replaced except the actual fuel injector lines, but since they are under pressure hopefully they are clear. Can the pump be disassembled and cleaned?

 

[jinman]

Brian, it is very hard to find any info on the fuel pump in the entire Repair Manual. The one block diagram even has it shown in the wrong place. I used to tell people it was just before the filter, but it is not, it's after the filter. Everything I've found replaces the pump as a unit and doesn't show a breakdown. It's an $80+ part. You could probably remove and backflush it for trash. I think you might carefully remove the cover too. It is shown on the engine block diagram in the parts book. They don't even show it in the engine fuel section. On mine, the hoses are painted the same color as the engine, so it must come from the engine assy line already installed in the Shibaura plant in Japan.

 

[brianb33]

Thanks jinman, I appreciate you digging into this for me. I will try the backwash and see if I get anything out. The most annoying issue I continue to have occurred again yesterday. After the tractor had been running and working (discing a pasture) for a couple of hours I stopped to knock a branch off of the loader and I throttled down too quickly. When I do that the tractor tends to stall. When I immediately try to restart it will crank but not fire (range in neutral, parking break on, PTO off, seated). After it sits a few hours/overnight it will crank right up. I would have thought that a warm motor should be able to fire right up. If I ease off the throttle more slowly it will idle just fine and not die. After running for hours there should be no air in the fuel lines so I don't get why it has to sit a while to restart after it had been running fine.

 

[jinman]

Brian, I would check your fuel cutoff solenoid. It's about 1" diameter and 3" long sticking out of the injector pump just right down under the filter as shown below. If could be heating up and maybe binding so it does not fully retract when you go to restart. It could also not be fully engaging and cause you injector pump to have fuel starvation. The solenoid just unscrews from the injector pump after you remove the single spade connector. If it is hot or shows heat discoloration, you may have found your problem. A few of us have had problems with it. It's not a common problem, but it does happen.

 

[brianb33]

Brian, I would check your fuel cutoff solenoid. It's about 1" diameter and 3" long sticking out of the injector pump just right down under the filter as shown below. If could be heating up and maybe binding so it does not fully retract when you go to restart. It could also not be fully engaging and cause you injector pump to have fuel starvation. The solenoid just unscrews from the injector pump after you remove the single spade connector. If it is hot or shows heat discoloration, you may have found your problem. A few of us have had problems with it. It's not a common problem, but it does happen.

View attachment 308096

Thanks, I'll give that a try. I was leaning in that direction, the tractor house said the same thing.