My 01 use to change tone about 2500- 2700RPM and I believe that is the pilot injection shutting down. Lately it doesn't do it can this be related to the fuel pressure regulator that is possibly the cuase of my lopey idle.

I have not had that problem, But from what I have Read the lopey Idle could be caused buy the Rail Pressure Regulator or the Fuel pressure Sensor.

I can't hear my pilot injection shutting off anymore like I use to, but I don't have a lopey idle, either.:confuzeld

At first, the pilot injection shutting off occurred frequently. It learned not to do it after awhile! My idle still good.

Learned?

Everyone knows I'm off my rocker....

But, it seems to me that the pilot injection on/off is somewhat regulated by the accelerator position.

Like, when I "creep" up to 85 MPH or so http://www.dieselplace.com/forum/images/smilies/wink.gif, I rarely hear the rattle. But if I'm kinda doing a power blast and I'm on 'er, like on this one hill right before I get home and I got 15-20 psi boost, then it comes on, sho tang.

Not that I ever break the speed limit or recommend that you do http://www.dieselplace.com/forum/images/smilies/hihi.gif

Unless you're getting outta the way, of course http://www.dieselplace.com/forum/images/smilies/biggrin.gif

Is it possible to have an injector that has the pilot injection off at idle or dosn't work at all? My truck seems to me noiser than it did when it was new. A kind of thump at idle. Some trucks that I have heard are quiet and smooth. Truck runs good and has great power.
Denny:(

How bout some action on this thread.:ro)

Denny

Everyone knows I'm off my rocker....

But, it seems to me that the pilot injection on/off is somewhat regulated by the accelerator position.

Like, when I "creep" up to 85 MPH or so http://www.dieselplace.com/forum/images/smilies/wink.gif, I rarely hear the rattle. But if I'm kinda doing a power blast and I'm on 'er, like on this one hill right before I get home and I got 15-20 psi boost, then it comes on, sho tang.

Not that I ever break the speed limit or recommend that you do http://www.dieselplace.com/forum/images/smilies/hihi.gif

Unless you're getting outta the way, of course http://www.dieselplace.com/forum/images/smilies/biggrin.gif There is a TSB on the overdrive lockout that describes the operation of the pilot injection. One thing to note is that it is not used when the rpm goes above a certain amount OR when the fuel used goes above a certain amount. SO, it seems to make perfect sense that if you put your foot into it the pilot injection might shut down due to exceeding a certain fuel flow through the injector.

Also, in the winter, with less BTU content in the fuel, you will be using a greater amount of fuel and therefore the pilot injection would shut down "sooner" in some cases due to exceeding the fuel flow limit (versus the rpm limit).

- jeff

even a blind squirrel like me finds a nut once in a while http://www.dieselplace.com/forum/images/smilies/biggrin.gif

But is it possible for an injector or injectors to not have pilot injection working below 2600 rpm?

Pilot injection primary purpose is to quiet the diesel noise below that rpm. I'm asking if the above statement is possible explaining a noiser diesel at lower rpms.
Denny:help2:

But is it possible for an injector or injectors to not have pilot injection working below 2600 rpm?

Pilot injection primary purpose is to quiet the diesel noise below that rpm. I'm asking if the above statement is possible explaining a noiser diesel at lower rpms.
Denny:help2:
Are you asking when driving the truck under normal circumstances (not WOT or heavy accel) the pilot will turn off below 2600rpm?

Under normal driving conditions and at idle in park. Again, is it possible to have one or more injectors not in pilot mode thereby not stifeling the diesel rattle for those injector positions that are not working resulting in a noiser engine?
Pilot injection is active to about 2600rpm.
Denny:(

I don't believe so....that doesn't sound normal.

I hear that injectors can make a racket when they're going south, but I haven't heard that for myself. You may want to send a PM to dmaxallitech or post in the tech forum.

If they're making a racket, I would at least check the oil for diesel smell and proper level and make sure they're not dumping fuel into the crackcase.

I may be overreacting, but a I've seen more than a few threads where noise led to bad things, and I wouldn't want you to get too worried, but I'd have it checked out asap.