Ford New Holland 6640 injector pump issue?

ptfarmer · Mar 9, 2019

I am having a problem with my dad's 6640 (it's a rotary style looking, not the inline style injector pump) it seems to loose it prime on occasion after the engine has been shut off. It doesn't matter if the tractor has been sitting for a minute, or for a week. It doesn't have a lift pump separate from the injector pump, it only has a hand primer on the filter housing. When it looses it's prime it take a bit of the hand primer to get it to run again. All the fuel lines are good, I even dropped the lower tank beneath the cab, and made sure there was no junk in it (I also replaced the non working fuel level sending unit). I also replaced the electric fuel shutoff on the injector pump so the question is, is the injector pump itself starting to go bad??

Dieseltech · Mar 9, 2019

If it runs fine I'd think it's loosing prime with air entering the suction side somewhere. If the fuel is completely full does it act up? Could be the and primer has a leak too. Suction side leaks can be hard to find as most times there's no fuel leak, but air. There is a chance the transfer pump blades and liner are getting worn inside the injection pump though. I usually replace them when the pump is apart for repair.

ptfarmer · Mar 9, 2019

Dieseltech, it will do it when it's completely full, the upper tank where you fill it is infront of the radiator so it has plenty of gravity at work.

ptfarmer · Mar 9, 2019

This used to be city of San Antonio tractor that mowed right of ways, and it did have a bunch of coolant put in the fuel tank long ago. I guess they thought that cap was for the radiator.

RickB · Mar 9, 2019

I was going to suggest the water separator seals until you said it starts hard with the front tank full. Perhaps the injection pump shaft seal is leaking. Are
you getting fuel in the crankcase?

ptfarmer · Mar 9, 2019

No fuel getting in the crankcase.

RickB · Mar 9, 2019

I?d pull an engine oil sample and verify there isn?t excessive fuel dilution an then probably pull the pump and send it out. Or just yank it and send it.
Antifreeze and injection pumps don?t play well together. Sending the injectors out too might save a scored piston or two.

Dieseltech · Mar 9, 2019

Does the hour meter work, and if so how many hours is shown?

Destroked 450 · Mar 9, 2019

I had this problem on a 5030.
Pull the hand primer apart and see if the check valves and seal are bad. The check valve in the hand primer hold the fuel up to the injection pump.
Their available on the site.

RickB · Mar 9, 2019

When the static level in the fuel tank is 12? or so above the injection pump it?s hard to grasp how a check valve is causing the problem. But it is easy
enough to check.

Destroked 450 · Mar 9, 2019

When it's pulling the fuel out of the lower tank it makes a big difference.

5030 was giving problems when it got below 1/4 tank.

ptfarmer · Mar 10, 2019

(quoted from post at 11:16:15 03/09/19) Does the hour meter work, and if so how many hours is shown?

It has 5009 hours on it, the hour meter works.

ptfarmer · Mar 10, 2019

(quoted from post at 19:37:37 03/09/19)
I had this problem on a 5030.
Pull the hand primer apart and see if the check valves and seal are bad. The check valve in the hand primer hold the fuel up to the injection pump.
Their available on the site.

I will probably go ahead, and get a repair kit or whatever (start with the inexpensive stuff first).

ptfarmer · Mar 10, 2019

(quoted from post at 20:07:26 03/09/19)
When it's pulling the fuel out of the lower tank it makes a big difference.

5030 was giving problems when it got below 1/4 tank.

It will do it when the fuel level is still above the injector pump on the upper tank.

Ford New Holland 6640 injector pump issue?

ptfarmer

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