Bad Injectors? (LB7) Newbe

[DanG]

I just bought a used Chevy 2500HD 2002 LB7 with 70,000 miles on it. This is my first diesel. Not knowing what a bad injector may sound like, can I do any test at home without asking a dealer to check to my engine. It has a steady knock under load that seems to me to be the same 1-2 cylinders. It doesn't smoke at idle and get OK MPG (17-20). The exhaust sounds uneven, I thought a turbo would smooth it out more. It has a strong smell in the cab when I back up the truck, this might be normal? I asked my Chevy dealer to do a scan and they blew me off. Can I tell from a tuner that might have the active data scans(Predator for example), or do I need to find another dealer to know if this noise is normal because I don't know? I will be towing a 6,000lbs trailer in the winter and don't what to wreck the motor if that possible to do with bad injectors.

If I buy a tuner, any suggestion on the best MPG tuner pulling a 6,000lb trailer?

Any dirt on this VIN# would be great. VIN#1GCHK231X2F197661

No fuel in oil (changed)
Fuel filter (changed)
Air filter (changed)
Added diesel injector cleaner

Stock 2002 2500HD LB7 70,000 miles

[Mark Rinker]

Welcome aboard. Your first post was not only full of all the correct information and observations, your idea to add fuel treatment after fluid and filter changes may very well clear up your problem.

FPPF makes a great additive. I run it in my trucks, its available from one of our supporting advertisers www.kennedydiesel.com . Good stuff and its quieted down one of my trucks that started making more 'diesel' noise than normal, without any other signs of injector failure.

If you start seeing any visible white smoke at idle, get it in to a dealer that will proactively diagnose the problem.