Injector failures

Usually the electronic part of it. These new injectors can fire off multiple injections per power stroke.

 

Also bad fuel. Diesel today is not nearly as lubricated as is was before ulsd. And just junk in fuel, tolerances on today's injectors are so tight the slightest spec of dirt can screw them up.

 

Electronics, and tips. I’ve actually had more injector problems due to ####ed up spray patterns than electronic failures. I’ve never seen anything foul injectors like an Acert will. I’m not too quick to throw away a $600 injector until I have to. I dug out my old Beechwood block from cleaning up fuel nozzles for the PC’s. Works the same, a little rub and shove ‘em back in there you’re good for another 150k. Just an awful lot more stuff in an Acert head to take apart to get them out. Even an overhead set on those engines will make you cry.

 

Water or contamination in fuel is biggest killer. The tolerances in today's fuel systems is way tighter than stuff of 70's and 80's. This is from Delphi' newest common rail DF21 injector used by Paccar, Volvo, and Caterpillar:
In the firm’s F2 NCV (Needle Control Valve) Euro VI valve assembly, the 2.0-mm valve has a 1-micron clearance, with 4 microns of valve lift. For the new 1.0-mm valve, the stem clearance is reduced to just 0.5 micron, with a valve lift of 1 micron. Indeed, even handling the valve components could affect the finish, so vacuum grippers are used to place the pins and valves.

Delphi is using cubic boron nitride (CBN) grinding abrasives to match-hone the pin and bore diameters. Orifices are laser drilled, as a conventional drill bit stem would not be strong enough.

Every DFI 21 injector will be tested to 3,600 bar (52,200 psi) before calibration. Delphi is currently manufacturing beta-level samples of the injector in batches of several hundred, using production-representative processes that are readily scalable.
To put into perspective, the clearance of needle control valve to bore is .5 micron or 0.000019685039370079". Pretty tight.