Ford 3400 injector pump problem

BSer · Feb 8, 2010

i have 2-3400's and the one is trying to break me. The injector pump failed[we think]. It is the rotary style and we put on one off a 3000 we had retired;can't get fuel out of the pump to the injectors. Tried a third pump off another retiree,can't get it to put fuel out either. The mechanic knows what he's doing. Have I hit a bad series of pumps or is something sticking up from sitting? I won't put a $900 pump on a $1500 tractor,very open to ideas,theories or ridicule.

Fordfarmer · Feb 8, 2010

Are you sure you have a -GOOD- fuel flow from the tank? There is a screen on the pickup in the tank. Also bled the system at the filter and the pump? Very unlikely you found 3 bad pumps.

pete 23 · Feb 8, 2010

Poor man's test bench, bolt a piece of iron to tractor frame, bolt pump to it and turn pump with a speed handle wrench. Only line you need hooked up is from filter to pump. I used to do this when I repaired the Roosa Master pumps so as to save a lot of cranking with starter and to be sure it would shut off also.

oj · Feb 8, 2010

Fordfarmer has a point, more likely that the problem is related to the fuel lines/filters/lift pump than the injection pump, especially as you have tried another (3) injection pump. My first guess would be a lift pump on it"s way out, diafram with a hole in it maybe, otherwise either a clogged filter or a bad pipe sucking air. You should get a good stream of diesel out of the bleed screws once the machine is bled, if it just dribbles out then the problem is related to the fuel supply to the pump, change the filters and check the filter in the tank (if you"ve had the tractor from new it should be there, if you bought a used tractor someone may have taken it off, and so a pipe might be full of crud, maybe blow the lines back from the lift pump to check they are clear).

forddoc · Feb 8, 2010

sounds to me like a stuck metering valve in the injection pump, very common on the rotary pumps, to access it the gov, cover needs to be removed. Get a manual if you don't have one. so you can make sure you know what it is that you're getting into. otherwise you'll do more harm than good.

RodinNS · Feb 8, 2010

Open the pump housing bleeder and see if you've got fuel shooting out when you crank. If you don't you have a supply problem, likely a blocked line. If you do have fuel, you have a metering valve problem. Proceed as Forddoc suggests... or shell the money and send it to a pump shop.
Don't worry about the transfer pump. I highly doubt it's the problem.

Rod

Anonymous-0 · Feb 9, 2010

Mechanic said faulty pump (not). A dirty injector failed to completly close. The engine piston would blow all the fuel out of the pump. Engine ran when the injector was disconnected. (Cap pump tube with some rubber hose that's plugged.)
Borrowed an injector tester and pumped fuel through the clogged injector while still in the engine (running). Then flushed out everything and replaced filters. Fixed

RodinNS · Feb 9, 2010

I'm at a loss for words....
What was this on?

Suffice to say, if you did this on a CAV rotary pump, it had a bad delivery valve.... which means the pump was very much bad.

Rod

Anonymous-0 · Feb 9, 2010

Doesn't cost anything cracking lose the lines one at a time. Odds of three bad pumps are astronomical, has to be something else.

RodinNS · Feb 9, 2010

Actually, the odds of three of those particular pumps being bad after all having sat for who knows how long.... are not that high at all.
Again, if the pump body has pressurized supply to it's bleeder and nothing is coming out the injector lines, it most likely has a stuck metering valve.
If it can't shoot fuel out the pump body bleeder when cranked, then it likely has a primary supply problem. Given the present temperature conditions; probably related to ice.

Rod

Ford 3400 injector pump problem

BSer

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Fordfarmer

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pete 23

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oj

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forddoc

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RodinNS

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Anonymous-0

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RodinNS

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Anonymous-0

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RodinNS

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