Rotary Injection Pump Diagnosis

Ken Macfarlane

Well-known Member
Got a Delphi DP210 I am trying to solve here. Its quite a bit like a Lucas CAV mechanical governed with some extra emissions junk on it.

It always used to have a bad stutter or misfire coming off full load too fast. To me thats related to the timing advancing or retarding too far. Could live with that.

Last day of haying this year after a fillup it got such that it had less and less power, and would instantly stall with very hard restart if you suddenly reduced throttle setting. At same time turning the key off (solenoid stop only on the pump) caused a long run on before shut off instead of normal quick.

Checked filters and yup goop and water. Cleaned, primed, good flow to the pump inlet. Added atf and cleaner and have run the tractor 3-4 hours with little change despite no water.

Blew out lines to tank incase there was a restriction on the return but it seemed ok. Removed inlet connection on pump as there is supposed to be a screen but didn't find one.

The darned thing is a keyless pump so engine has to be put to TDC on #1 properly before you lock the shaft to take pump off so trying to figure out if it has to come off.



Delphi certified pump shop wants 2000$ to diagnose and minor overhaul on pump which I don't happen to have. Seems a bit steep given there are only about 200$ of things they replace.

I'm thinking the fuel delivery valve is the common part to the recent problem, the shutoff plunger I think is supposed to push that arm to 0 setting to shut off engine. The throttle linkage I think just pulls on the governor linkage which runs the valve. The boost diaphragm just moves to let fuel valve linkage travel farther under boost.

I just can't figure out why even just a small sudden reduction in throttle lever position causes an immediate hard stall that makes restart impossible for 5 mins.

Anyone ever work on these suckers?
 
I did in a way, the 1/2L filter housing was cleaned 3 times using the electric lift pump to fill from fresh fuel in main tank. After 3rd time supply has stayed clean. This was done right after finding crud in the tank.
 
If you had water in the fuel in the past there is rust stains causing the metering valve to stick in no fuel position on quick deceleration. The shutdown solenoid may need replaced if the port closing tip gets mushroomed over, or plunger is sticking too. The tip closes off the transfer pump fuel port for shutdown, it does not move the metering valve to shutdown like Stanadyne pumps do. If you can get it started again set the speed wide open, then back to idle but when tach is at about 1200 open throttle wide again. This will help move the valve off and on to hopefully free it up, but it may take several times.
 
Can't get it to run to max governed speed anymore, it will creep up to maybe 1900 max under no load. I suppose that suggests the meter valve is sticking or I'm having fuel delivery problems to the metering valve.

Re trying to force the metering valve to exercise, I've done this about 50 times now, really tough as the slightest sudden drop in throttle position kills it dead with really tough restart. If you creep the speed up and down you can freely go from idle to the 1900 or so. If you increase throttle suddenly the rpms overshoots badly too.
 
When speeds overshoot or underrun like you have then metering valve sticking is verified. It may get better over time if you can get it to run at all. If not it will have to come apart.
 
Thank-you for your help! If the metering valve has got rust on it I'm guessing the advance ring and valve are the same.
 

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