Topic of this is plant machinery not ATV, but still a warning worth flagging up. All internal combustion engines rely on good filters..

Not long ago had a diesel injector pump on a digger that failed very quickly after rebuild. Initially was blaming the exceptionally dirty fuel tank.

Why though, even if the tank *was* really dirty, did the muck manage to get through the brand new filter the repair guy had installed?

Well I found the answer today. Spent all day really going to town on the whole fuel system & getting it all tip top.. feeding the fuel from the tank into a decent 30 micron filter / water separator, then into a 2 micron filter / water separator, then finally for good measure into a cheap inline cartridge paper filter the same as the one that was on it before, before the fuel finally reaching the injector pump.

The cheap inline cartridge paper filter was given to me by the guy who originally fitted my reconditioned fuel pump. He'd bought 2, and fitted just the one. He thought I should run it for a while then after a bit, remove the first one and replace it with the second fresh one.

Today I couldn't seem to bleed *all* the air out of this third in line cartridge filter, so I figured there must be some sort of internal arrangement underneath the paper concertina element that was stopping the air getting out. Had a brainwave - hey, why don't I smash up the old filter with a hammer so I can see what's inside and get a handle on how to bleed all the air out.

Did so and guess what I found.. the innards of these filters are unsealed such that only some of the fuel passes 'by luck' through the paper element. The rest entirely bypasses the filter element and continues unobstructed right past the filter, through a gap probably a good 0.5mm or more wide, and on into whatever's next.

No wonder I ended up, with just one of these cheap inline filters as the pump's only protection, having to fork out £400 for 2 pump rebuilds instead of £200 for just one!

Looks like my injectors are goosed too, now :-(

Be careful with cheap filters.

 

2 micron is way to tight all your doing when yo get to that size is restricting the fuel and actually filtering all the additives out of the fuel. No need to go below a 10 micron filter.. 3 filters on the fuel system is overkill with the way you had it filtered you are filtering all the additives out of the fuel and that is causing damage to the fuel system.

 

I removed the cheap inline filter today because I thought well, I guess it's doing nothing anyway after the 2 micron one (apart from the unions being hard to seal & letting a bit of air in, think it was that stopping it starting rather than dead injectors). Re-piping it all to go down to just the one filter would be a bit of a pain now it's all done but, the 2 micron cartridge in the second filter would be dead easy to change out for a coarser one. I'll see if I can ebay up a 10 micron cartridge.

The manual's actually got a fuel flow requirement listed in cc per minute (along with a helpful little diagram suggesting how to measure it with a stopwatch and a beaker) so I can double check it's not restricting too much, thanks for the headsup

Caught a load of muck already in the 30 micron filter, looks like it's actually rubber perishing off the inner walls of the line from the tank. Got new lines all the way from the outlet of the first filter to the engine now so hopefully the injectors are now safe.

Going to do the tank to filter line when the tank and engine come out, gotta do the starter motor & it's a pig to get to

At least it starts and runs now :-)

 

ya i would get rid of that 2 micron as you are just pulling the additives out of the diesel as well as some of the lubrication of the diesel and over time that will damage your system again... If you go to some of the manufacturer websites like Fleetguard, or Donaldson sometimes when you cross the filter it will give you other options for the same filter but in different microns