How do you test for a bad injector on an '03?

[Badunit]

How do the service guys go about determining if one injector is not performing the same as the rest. Similarly, how do they go about determining if one cylinder is not performing the same as the rest (due to whatever reason)? I've heard that on the 04. 5's that there is an injector shutdown test but I don't see such a procedure in my '03 powertrain diagnostics manual.



My engine has had a thump thump thump since it was new (or at least since it was nearly new). It is present at a low volume at low RPMs, peaks in volume at 1800 RPMs and dies away nearly completely above 2000 RPMs. You can hear it at the exhaust pipe as well as in the engine compartment and in the cab.

 

[truckstom]

Since the injectors are electronic, they can shut them off one at a time with a laptop computer and the correct software.

 

[Badunit]

Wouldn't this also require the truck's computer to have the programming to accept and respond to such a command? Are you sure the '03 has this capability? Since I'll probably have to pay for the diagnosis and testing if they think the sound I'm hearing is "normal" (unless they find a problem), I want to be able to direct them in exactly what I want done. If this can be done on an '03 it would be a quick, easy, and relatively cheap way to narrow down the problem. If not, what would they have to do?

 

[Johnstra]

Badunit - Yes, this procedure absolutely works on an '03. I had it done to mine just this month. The service department will have a diagnostic computer that plugs right into the service port under your steering wheel. To test for an injector problem, shut down each injector in sequence and load the engine slightly. A bad injector will emit a very noticeable knock when you load it. When the faulty injector is turned off, no knock will be heard under load. The procedure takes no more than 5 minutes to perform.

-john

 

[brickerd]

Another thought for us DIY people. What about using an infared temp guage? It would tell you if all cylinders were firing the same amount, etc. All cylinders should be about the same temps.