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Bleeding the fuel system on a tractor is a relatively straight forward job.  However, it is not uncommon for people to contact us saying they have fuel to the injection pump but cannot get fuel to the injectors.

Recently an owner of a TEF-20 wrote in thinking he must be doing something wrong, but he didn’t know what.  To use the gentleman’s own words, he was completely goosed“!


The Normal Procedure

So lets start by taking a look at a video of how you would usually go about bleeding a diesel fuel system.  The video below is of a MF35 with a Standard 23C engine, but the steps are similar for other tractors.  We need to get air free fuel from the fuel tank to the fuel filter with assistance of the lift pump, then air free fuel to the injection pump and then to the injectors.


Fuel Not Getting To Injectors

So why is our TEF-20 owner having problems?

The tractor in question has not been started for three years.  It is quite common for the components of a stood injection pump to seize.  Inside the injection pump there is a rack which engages with pinion teeth on the elements, rotating the elements which adjusts the amount of fuel delivered from zero to full depending on the engine requirement.  If the pump has seized in the zero fuel position then fuel will not be able to get through the pump to the injectors when doing the bleed cycle.

It is possible for either the rack to be stuck in the pump, or an element will be stuck which will be preventing the rack from moving.

These coponents can sometimes seize after only a couple of months of non-use.


TEF-20 Injection pump


If you take the vacuum belows off the end of the pump you should be able to move the rod (rack) that the bellows piston is connected to.  Don’t force it or you will break it, only apply gentle hand pressure to try and move it.  If it is stuck then don’t tap or hit it as it will damage it.  You would need to take it to a diesel engineers to have the seized element replaced if you have no luck.  With the TEF fuel injection pump you can also remove the cover plate to look inside at the components.