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fuel injection pump

J

joseph h moore

New User
My tractor HD-3 allis chalmers, my fuel injection has been rebuilt and tested over an over, however it is not pumping fuel, is there a internal mechanism to operate the pump internally, over the years I have restored all operating units and would not like junking my machine..I live in Ct and tractor repair men are like the vanished trade..who can help or recommend, all help appreciated..
 
I'm not sure exactly what your question is. I assume you've got a Roosamaster/Stanadyne rotary-distributor pump. Probably a DBG429 model. It is composed of two pumps and a governor all inside one "container."

The back has a rotary vane pump that has two jobs. #1 it can draw fuel from 20 feet below it and eliminate the need of an external fuel pump if wanted. #2 it delivers a flow of low pressure fuel to the 2nd pump. On later models like it also powers the hydraulic automatic advance.

In the center is a set of two pump plungers that are forced to move up and down by a cam-ring. They make the high-pressure, low flow fuel charge that goes to the injectors.

It is a "self contained" system and there is nothing else needed except injectors for the fuel system to work. That being said, an external fuel pump is often used to make filter bleeding easier unless the fuel tank is higher then the engine.
 
The pump was rebuilt, I had it installed but fuel is not being delivered to the lines to the injectors, the battery delivers the necessary revolutions required being fully charged but no fuel that is my problem and I do have the pump you described, saving your diagnosis for a mechanics understanding if I can find a new one..the other spent 9 hours without success..Thanks for the intelligent response..
 
Cranking speed is not essential for that pump to work if it's OK. I often turn them by hand and prime them before installing and that's pretty slow. On the engine when cranking it ought to spin at 150 RPM. You stated you had the pump worked on by somebody - so the question remains - was is fixed properly and did it work when you got it? If that pump was off - you could just squirt fuel into it from a hand-held squirt-can (or hook a fuel source to it with a hose) - and then turn the pump by hand and even at one turn per second it will prime itself and inject.

I think you'd better verify #1 that the pump is actually turning inside. That you can verify by removing the little rectangular timing window held on by two screws. Then turn the pump and see if half the parts visible in that window are turning. If nothing is turning - the shaft if broken inside. That shaft is designed to snap in two if the pump turns too hard.

Also, verify the pump is turned "on" via the metering valve linkage.
 
Seems odd it does not work on engine if it has been tested. Does it have a seperate stop cable? JD would know, and if it should be pulled out to run like AC tractors are, and pushed in to kill. Deere, IH, MF with seperate stop cables are all in to run, out to kill. Hate to think cable is in wrong position.
 
Might seem like a stupid idea to some, but I put a couple gallons of fuel in a clean container. Set it on the hood. Make an adaptor to the pump where the fuel goes in. Siphon feed into the pump.
After thought, have you cracked the inctor lines to make sure they are not air locked.
 
That is my problem, I opened the lines to let air out, and disconnected the return line to the tank, fuel still will not come up,however, I am going to see if I can mickey mouse your idea..I will try anything because working with this bit of machinery is a real joy..Thanks
 
The pump only has a lever mounted on the engine side, down it shuts flow off and upright opens internal port..I am going to try all suggestions. and grateful for responses..
 
Those pumps that come without electric shut-offs use either a two-lever or one-lever system. Two lever has one for throttle and the other for shut-off. Single lever has shut-off and throttle on the same control. Either way - there is a small push-on clip on the throttle-shaft inside the pump that makes the pump shut off by forcing the metering valve closed. Inside the pump - the only thing that can go wrong with it is . . . it can fall off. If it DOES fall off the pump will be always on and will not shut off. Not the converse.

If the pump won't pump fuel - I'd check the internal shaft and make sure it hasn't snapped in two, then check the position of the metering valve inside the pump. That is the valve that MUST be in run position for the pump to pump fuel. Very easy to get to. Just take the three bolts off the top of the pump, lift off the cover and it's right there. You can move it back and forth with your finger.

In regard to the injector lines getting "air locked." In theory, it's impossible with a good working Stanadyne pump. It is self-bleeding by design.
 
I am learning more each hour and feeling a lot better, having a better understanding with the previous explanation..now for a nice warm day with patience and a fully charged battery..thanks again,.will be on line when I am running...
 
I would try the tips put forth by the fellows that have posted below.

I have gotten Roosamaster pumps back from a re- builder that have the vane pump ring in wrong. It can be flipped for either direction of rotation. If it is in wrong then the vane pump will not work.
 
The pump was rebuilt by a Company in Alabama, I forgot about the little window..Thanks, today all the bits of facts are beginning to gell..I am printing them all for reference thanks..the rebuilder informed me 150= was necessary when installed..Thanks again..joe
 
If 150 RPM was the minimum necessary for that injection pump to work - many tractors would be in trouble. Most diesel tractors crank at around 300 RPM and the injection pump runs at half-engine speed. So, 150 RPM is the "normal" cranking speed for that pump and I know many times and situations - those pumps only turn at 75 or 100 RPM and still work fine. I have primed many, by hand by spinning at whatever my "by hand" speed is. Maybe 1 turn per second, i.e. 60 RPM?
 
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