dda injector

[chessie4905]

   Does the rack and gear assy inside the injector get lubricated by engine oil splash or by the fuel going through it?

[luvrbus]

Fuel cools it and lubes it

[TomC]

This is why you have two lines going to the injector-one to feed it and the other to return the unused fuel. All injectors flow more fuel than the engine can use to lubricate them. Good Luck, TomC

[chessie4905]

   Now to the reason for the question.......If an engine in bus hasn't been started in a few years and some injector control racks are stiff working, but not frozen, could you hook up an electric fuel pump before the filters to circulate fresh fuel through the injectors without starting engine? Would you need to bypass the mechanical pump while you did this?

[bevans6]

When I did that, I did each head separately, to make it easy.  I pumped in solvent into the fuel in line on each head and had a simple return line from the output of each head.  If you used fuel, it would return to the tank so no problem.  Where you plumbed the fuel in to the engine would depend on what kind of engine you have - my 8V-71 in an MCI has two separate fuel in lines - one to each head, and a cross-over.  I would bypass the mechanical pump if it was me doing the job.  It should only take a little while to free up the injectors.

Brian

[luvrbus]

I never tried it that way but have taken old fuel lines and pumped paint thinner through each injector 1 at time  through the in and catch it from the return side works sometimes.

It is best to remove the injectors for a good cleaning and if you tap the plunger on top with a rubber hammer it cleans one good the rack and the plunger then run a little Marvel oil and blow it out.

When they start gumming with the crap fuel of today it only gets worse years back one could set for 10 year without problems of gumming not that way today Brian's way will work if not to gummed up lot of times cleaning injectors in place it breaks the stuff loose then the plunger will stick down BTDT

[bevans6]

I actually got the idea from Don Fairchild, that's how he told me to do it.  I used a pail of paint thinner and a 12v fuel pump, some hose and some hose clamps and jury-rigged it up.  Took about 5 minutes to free up the injectors, but I ran it for about an hour per side.

Brian

[luvrbus]

Yea I remember Don telling you that, OT but that tool has not shown up yet the post office said it arrived they just cannot find it and they wonder why FedX and UPS kicks their butt

[bevans6]

Great that they are actually looking for that, that is a start.  I am running out of season up here, it may become a spring thing for me...


Brian