Help diagnosing possible injector issue

[BJMarshall]

Just bought an 03 QC 4x4 6spd with 120k. Truck ran great the first day we had it. Didn't run it hard or anything, but now it seems to have a problem. I don't know jack about these common rail engines other than what I have read on here.

The engine has a slight miss with a knocking sound, and some blue smoke. The knock doesn't sound quite like a rod. It seems to be a little more high pitched and not as loud. Engine seems to run good and has good oil pressure, but I parked it until I have some more time to look at it.

Cat mechanic was at the lot today to look at a dozer and I asked him to take a listen to it before he left. He said it sounded serious, but I don't give him much credit since he tried to crack the injector lines to determine which cylinder was missing and he couldn't figure out why the truck would go dead when he cracked a line. I'm just glad he didn't get hurt on our property. :-laf

Is there any way to determine what the problem is without just putting injectors in it and seeing if that fixes it?

 

[B.G. Smith]

There is a way to kill the power to individual injectors one at a time to determine if they are working but I don't know it it is something the average yard hand can do. When you crack the line on a rail you lose pressure to all injectors and that is why it died. Make sure you are not getting fuel in the crankcase. bg

 

[rashwor]

I can't help you other than say it may be a bad injector. A good dealer or a good diesel shop can hook it up the the computer and do the injector kill test. If there is a bad injector, this will most likely find it.



You probably know this, but just to reiterate: Don't crack the rail or injectors with these motors running. VERY VERY high pressure even at idle. It can kill.

 

[BJMarshall]

Yeah, I know about the lines, but I was surprised the Cat tech didn't know. The whole engine bay is covered with fuel now. The oil doesn't seem to be contaminated.

I'm going to see if I can find someone to check it instead of just putting injectors in it.

 

[CSkal]

"You probably know this, but just to reiterate: Don't crack the rail or injectors with these motors running. VERY VERY high pressure even at idle. It can kill. "



As per my local SM at the dealer, it already has claimed 1 life that he is aware of.