I have had the Bully Dog Power Pup programmer installed on my truck for about the last month or so. I have noticed that when I am driving and get off the gas and then back on slightly, I hear a slight knock, even when I am up to temperature. I live in Chicago and it was more noticeable when we were in the single digit temperatures recently. Once it reached the 20s, it is barely noticeable. When I return to the stock program, the knock goes away.

I have searched this forum and have heard some discussion about diesel timing knock, but nothing definitive if this is normal when these programmers are installed and if it is harmful to the engine. I have read that timing knock in a diesel vs. a gasser are different.

I have spoke to the folks at Bully Dog and they said that this is normal. At the 55 HP level they are increasing the timing, at 80 they are additionally adjusting the fuel pulse width and at the 95HP setting they are adding fuel pressure as well. Bully Dog claims this is not hurting the motor, but I want to see want everyone's experience is with this programmer.

The power is awesome as well as the fuel mileage. I am happy overall with the programmer, but do not want to hurt the motor, since I plan on keeping this truck a while.

Any thoughts would be appreciated.

do not worry about it, and it, not that bad at all compared to some boxes out there, from my testing, the boxes with a little timming rattle, ussally give the mileage,

That nock is a PITA. It's to bad you can't have more power without all the knock.

If you ask nicely maybe you can get it tuned back a bit( custom)? You will loose some power and milage but it will still be better than stock.

Play around with diesel fuel additives. You will learn witch one really adds cetane because your knock will lessen.

BTW whats you altitude?

I am in Chicago, IL, so we are just above sea level.

I am running it in the 55 HP mode right now (at least until I install the EGT and Boost gauges), so I really wouldn't want to tune it back.

Running the Quadzilla Stealth LLY (same basic tuning platform with different calibrations) on my 2005 does not exhibit anything excessive as far as timing goes. The 90HP file IS a little flighty in that it wants to take off when a certain APP threshold is crossed, but timing sonds are near stock levels by my ear.

My motor actually seems to be getting quieter the more it runs with the powerpup. It does make a lot more noise when compared to stock but when it's cold it seems like maybe the engine is getting more used to the power pup or something. But once it hits 180 it goes away so I've just learned to live with it.

The timing knock is not that much more that stock, but it is enough to notice it. I think the colder weather definitely makes it worse. I just want to make sure that I am not hurting anything in the engine.

Must be the cold! I live in Florida, and I have been using the 80Hp setting since the truck was 5 days old. LB7, 2004. I have not noticed any noise difference. I love it and I also pull a fifth wheel TT and no problems. I don't think u need to invest in temp gauge unless u go over the 80 Hp setting or you dawg it alot.

I live in S.E.Michigan and mine gets louder as it gets colder
(Nature of the Beast) . The PUP has been on ( 75 hp , 33 in.
tire & no gov. ) for over 10,000.0 miles and I have had no
problems at all . ):h

The timing knock seems to be fairly common with these programs.

Can any of the technical diesel gurus explain why this does not hurt the engines ?

This may ease the minds of folks like myself.

Thanks.

I do not think it has anything to do with the cold.

Either some trucks are more suseptible or some peoples ears are more suseptible.

Mine was so noticable that I had my program tweaked down a bit.

I agree with BRONCO!!!

I have now been running the pup on 80 hp setting since july and have no problems with it. i Have put around 30,000 miles on truck mainly driving highway about 65-70. Pulled my fiver with it twice,about five hundred miles, man does it have the power.

Still curious as to whether the timing knock is harmful to the engine.

The timing knock seems to be fairly common with these programs.

Can any of the technical diesel gurus explain why this does not hurt the engines ?

This may ease the minds of folks like myself.

Thanks.Diesel's run on knock.
That said, too much timing can be destructive..... definitive answer of how much is too much?
I do not know