Injector replacement need help 03 2500hd

[Ben R. Scott]

My truck is running real bad but still going. They say the injectors are clogged. It smokes blueish white smoke if stuck in traffic or at an idle for 5 minutes. I have 4 new injectors is there a way to tell which one is bad. Do these trucks have onboard code procedures that I can check without a scanner? Thanks Shade tree mechanic!

[DmaxMaverick]

Welcome aboard!

It does sound like you have failed injector(s). You will not be able to tell which bad ones to replace (the dealer can't either, in almost all cases). You should get 4 more and replace them all. If they are original, and one or more have failed, the remaining good injectors won't be far behind. Replacing them, even one, is an extensive job. Too extensive, IMO, to replace only individual bad injectors, take a chance there are other bad ones, or you replace the wrong one, among other reasons. Many programmers/scanners are able to show PWM and balance rates, helpful in diagnosing bad injectors, among other things. However, you will need a Tech II (or capable Snap-On, etc) to perform individual injector diagnosis (which is most often inconclusive). You can not scan/read DTC's (trouble codes) without a scanner. None of the OBD II equipped vehicles (1996+) have this capability. Code readers/scanners are available for a wide range of prices. Tens of dollars for simple readers (which ONLY display DTC codes), up to several thousand dollars for a Tech II (what the dealership and many shops use).

If you are planning on attempting the injector replacement job yourself, you'll need some special tools, a good service manual (www.helminc.com for the paper book version, www.alldatadiy.com for the online subscription version), and most necessary, the TDP article (http://www.thedieselpage.com/members/duramax/LB7InjectorReplacementc.htm) walking you through the entire process. The job isn't too bad for an experienced mechanic, but is time consuming and very critical of details (and cleanliness).

[More Power]

If it's just one injector causing the white smoke at idle, and if it's easy to duplicate, a Tech II can be used to disable one injector at a time, which can be helpful to find the smoker.

Jim