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I’m looking at a neighbour’s 2010 DF404G2 tractor. The tractor was hard to start during the cold weather. The owners drained all the fuel, filled the tractor with winter diesel and started it up. The tractor quit about an hour later. They bled the fuel system again and it started up but quit about 15 minutes later. It hasn’t run since. The owners had a fellow look at, but after several visits he hadn’t found anything.
At this point I got involved. I’ve inspected the inside of the fuel tank (without draining it) and don’t see any contamination. I’ve checked the supply hoses from tank to injection pump. The inlet screen at the lift pump was blocked up with what looked like rubber debris. I removed the lift pump, cleaned the check valves, and check the operation of the primer and lift pump. When I tried to bleed the system things went as planned until it came time to get the air out of the injection pump. After between 250 and 300 stokes of the primer there was still no sign of fuel from the bleed point on the top of the pump. When I loosened the banjo fitting at the inlet to the injection pump the fuel squirted out with some pressure.
My questions:
Was it the injection pump lubricating that came out when I removed the lift pump? Can’t think what else it could be but would like to be sure.
The tractor manual says the primer should lock in the down position. This one doesn’t. Does this matter and can it be repaired or does it need replacing? Other than not locking down it works fine.
Why won’t the injection pump take fuel, and what can I do about it?
Thanks in advance for your help,
Dave
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First of all, that “rubber debris” is diesel bugs. Black is their color when they are dead, brown when alive. They are micro organisms that live and multiply at the fuel/water-moisture interface. Lots of info online about them. They are highly corrosive and can destroy an injection pump and injectors. I’ll speculate that you haven’t changed the fuel filter, and that it’s plugged solid with bugs. I have seen bugs bring a 10,000 HP diesel to it’s knees. You will need to drain and thoroughly clean the fuel tank and fill with fresh fuel treated with a biocide. You will need to biocide treat for at least two subsequent fill=ups. One of the encounters you may experience is a stuck rack due to any corrosion, but you may get lucky.
Just draining the tank won’t do much good unless you clean it too because the bugs will be on the top and tank walls. Also check the sediment bowl screen and in-tank screen if so equipped.Account deleted.
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The tank screen looks good from the top and The fuel filter was replaced when the fuel system was drained and refilled with winter diesel. The primer pump puts lots of fuel to the inlet of the injector pump so I don’t think the filter is plugged. I was turning the primer clockwise; doesn’t feel like there’s any threads in there at all.
I’ll drain the tank tomorrow and have a better look at it. With the fuel getting to the injector pump inlet any thoughts on what’s stopping it?
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I think the position of the plunger does not make the engine not run (but it should be screwed down when not in use) I have heard of the interior of the Chinese hoses to breaking down . I have a 20 hp df tractor and the inj. pump on it has a oil reservoir in the pump, has this oil level been checked? It does not hold much and is slow to fill .15w-40 Engine oil is ok to use in it. But back to the hoses could you have a vacuum leak , so the suction from the manual pump is not overcoming the leak and not priming? Or maybe there is something with the plunger since it will not lock down. Let gravity help you find where fuel is and where it is not go from connection to connection . Did you prefill the fuel filter before replacing it , it will take a ton of pumping to fill it if you did not fill it.
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There are two banjo bolt fittings on the injection pump fuel cavity, one for IN and one for OUT. The one for OUT is the return line to the tank and it has a pressure regulating check valve in it. It can be identified by either a “bubble” or a 6mm bolt in the head. Loosen the OUT banjo bolt and operate the priming pump – you SHOULD get fuel. There is a remote possibility that the check valve is corroded closed and the fuel cavity is air bound. This is all based on the assumption that all of the fuel lines are are good.
To answer a previous question, no, the oil sump and fuel cavity are separate reservoirs. The injection pump and governor share the same sump, and use engine oil. The priming pump plunger must be held down while turning clockwise. If the plunger is allowed to remain up there is a chance air could be drawn into the fuel system. If you are expecting to see fuel at the injectors from using the priming pump, don’t.
What David said about pre-filling the fuel filter, this is a MUST.Account deleted.
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Well, the tractor is running fine this morning. It came to life quite nicely on the second round on the starter. My problem with not being able to get fuel into the injection pump was because I had loosened the wrong plug. Teach me to look at a photo with an arrow pointing to the bleed port without putting my glasses on. Silly me. What is that large plug just behind the bleed port for? This is my first encounter with a Chinese tractor and I quite like them. The documentation on the other hand not so much.
Thanks for the help, guys. I suspect I’ll be looking for more.
Dave
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The fuel systems on these tractors is a typical Bosch style inline system and with few exceptions is used on virtually all small diesel engines. Glad it’s up and running. Reminds me that I need new glasses. Without a picture I don’t know what plug you’re referring to.
:yahoo:Account deleted.
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