MF 203 Air bleeding Injector Pump

fpappal · Feb 22, 2016

After a complete engine rebuild I made my first attempt at starting my MF203 regular inject diesel. I was not successful. I had the injectors and injector pump rebuilt and replaced both fuel filters. The lift pump is also new. The book tells me to manually pump until fuel comes out of primary filter, then do the same for secondary filter, then the top screw on injector pump, then bottom screw on injector pump. That all worked fine and I had a good stream of fuel from each of those points. At this point I opened the line to the first injector and turned the engine over. Very little fuel came out, literally a just a few drops oozed out. Same goes for the other two injectors. How much fuel should be coming out of these lines when they >are loose? I was expecting quite a bit of spray.

I repeated the above sequence and there was quite a bit of air that came out of the top bleed screw on the injector pump. However it is now to the point that no air comes out but I am still not getting much fuel out of the lines that feeds the injectors.

Any suggestions?

Brendon Warren · Feb 22, 2016

Keep at it sometimes they're a bear to get to bleed. Sometimes its easier to give them a tow if possible.

Bob NY · Feb 22, 2016

I have a later 65 with the direct injection engine. I have found that I can bleed all the injectors by cracking one line at the pump and cranking the engine.

Phil Tibbetts · Feb 22, 2016

Did you bleed the bottom screw on the injector pump before bleeding the top one? You don't need to remove the injector line, just unscrew the nut a turn. I've even loosened a couple of the nuts until it starts firing. IMO

Dieseltech · Feb 22, 2016

The lower pump bleed screw is most important, can't have ANY air at all, the top one can be bled later as it's to help keep internal linkage from rusting from trapped air. Each injector should have a small shot of fuel with the line loose and cranking engine. Also make sure if Wix/NAPA filters are used the top groove at the outer lip does not have an O ring in it by mistake, that's the filter inlet. CAV filters flow is different and don't have that issue. Made lots of service calls on the NAPA filter to remove the extra O ring, cause guys think it needs it there..

fpappal · Feb 22, 2016

Which fuel filter are you talking about? The primary or the secondary? I purchased both filters directly from MF. The primary filter is a metal canister and the element sits inside of it. I had a heck of a time getting the old rubber o-ring out of the groove that the canister sits in. I did replace it with a new one. The secondary filter looks like an automotive oil filter, the brand is Delphi. I put in a new o-ring for that one too. My injector pump is a CVA.

fpappal · Feb 22, 2016

The owners manual I have says to bleed the top screw first until all air is gone. Close it. Then do the bottom one. I bled it a few times and quite a bit of air did come out of it. Eventually from what I can tell the air is finally out of it however minimal fuel is making its way out of the pump.

fpappal · Feb 22, 2016

I actually tried to do that but still no fuel was coming out of the pump. Must be there is still some air trapped in it. I wore the battery down so I won't be able to try again until tomorrow after work.

fpappal · Feb 22, 2016

Is towing it any better than turning it over with a good strong battery? Unfortunately towing is not an option. If I pull it out of the garage there is a good chance I will not be able to get it back in! Doesn't help that there is a foot of snow on the ground as well.

Jack in NB · Feb 23, 2016

Two thoughts.

Is the fuel shut-off lever fully forward?

And I don't know if it helps any, but I feel that opening the throttle fully delivers more fuel through the lines to the injectors, thus speeding up the process.

ptfarmer · Feb 23, 2016

The lift pump usually has a lever so you can pump it to bleed it without cranking the engine until you get fuel to the injector pump. Once you get fuel to the injector pump, then you crack the injector lines open at the injectors, and crank it over until you see fuel coming out of the lines at the injectors. Then tighten the injector lines, and it should start.

fpappal · Feb 24, 2016

I finally have fuel coming out of each injector line, not a ton, but each line is dripping with fuel. I tightened them down but the engine still won't start. I feel as if the pump is not generating enough pressure to open the actual injectors. I paid $750 to have the pump rebuilt so I am not sure if this is really the problem or not. Also paid $250 for each of the injectors to be rebuilt. I thought it was a lot until my MF dealer told me that was a pretty good deal!!

While cranking the engine over I sprayed a little starting fuel in the intake. The engine made a heck of a clanking noise when I did that, almost like extreme engine knock. I got nervous so I didn't try it again. What more can I do at this point?

ptfarmer · Feb 24, 2016

With the lines loose at the injectors you should have got a bit of spray. Who rebuilt the injector pump?

fpappal · Feb 25, 2016

Yes, it is more of a slow drip coming out of each line. D&W diesel rebuilt the pump and injectors. They came highly recommended
from quite a few people. I am located in central NY, just north of Syracuse.

ptfarmer · Feb 25, 2016

I would call them, and see what they say about the injector pump since the fuel supply to the pump doesn't seem to be an issue. On other tractors that use the same injector pump don't even use a lift pump, they just let it gravity feed the injector pump through a filter. But the ones with a lift pump are a lot easier to bleed.

MF 203 Air bleeding Injector Pump

fpappal

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Brendon Warren

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Bob NY

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Phil Tibbetts

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Dieseltech

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fpappal

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fpappal

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fpappal

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Jack in NB

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ptfarmer

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