Hey all. Little paranoid, but here goes....

Noticed a noise that has me wondering if it is an injector knock. If I didn't know about the injector knock, I would think if might be a main bearing. Truck has about 90,000 KLMs (56,000 miles) on it. Its not alway present. Seems to come and go.

Can someone explain what "injector knock" is? What it does/what causes it. Stuff to keep an eye on, what to listen for....etc. Truck seems to run fine. No mods, except exhaust. Truck was built in Sept '01. 02 model. Run additive, but when started it had about 50,000 KLMs (31,000 miles) on it.

Any thoughts would be appreciated.

Also.....the knock isn't very loud, at this point in time. But I think I notice it.

Kind of sounds like a ping heard in a gasser, usually only on one cylinder.

I have a similar sound. I've asked the dealer to look into it, said everything was ok. It happens after approximately 1500 RPMs and increases with engine speed all the way to red line. If it was a gasser I would think it was pre-ignition.

What is the cause? A dirty injector or is an injector going out???

MaxRock

At what RPM is this noise happening at? 2500-2800RPM the pilot injection cuts out and they get louder. Is the noise you hear differant than the cutting out pilot injection?

I notice mine at idle. Can't say for sure about higher RPMs. Not sure if it is the engine "loosening" up?

I get that sound too. It is the "one bad lifter tapping" kind of sound. I get it at engine speeds above 1800 RPM clear to redline:eek: It is very different than the Pilot Injection off sounds. At least with PIO, you can tell that it is running on all 8!):h

I have noticed that it is varies with different kinds of fuel. The knock is much more pronounced with straight #2 dino, as opposed to my B5 soy blend. I have also noticed that it is the worst when I am on a full tank of fuel, gets better as the tank draws down, and is essentially gone by 1/4 tank. I had a F_rd that had a problem like this, but it was just the opposite (louder as the tank was emptied past 1/2) and that was traced to a faulty fuel pickup. I do not believe that is the case here.

All of the balance rates are +/-2 or less. Killing individual cylinder under acceleration or at idle has shown me nothing, as well. So much for the Tech II diagnosing the "bad one".:(

If I hadn't noticed the fuel level association with the noise, I would have thought it was just the F_rd and D_dge tailgates being "eaten" by the fan blades.):h

Sound has a deeper tone....