Hey guys,

I just added my CAI last week and my TB last night. I reset the PCM both times by disconnecting the battery. I have about 25 miles since the last reset and I decided to watch my knock sensors and retard today while driving around. I keep getting a small amount of knock retard (>1 degree) during WOT and if Im moving on the freeway and floor it to get it to downshift, the knock retard will sometimes go up to about 4.5 degrees at most. And the KR is only there for a couple seconds at most and then it goes right back to 0 again. It isnt very consistent and under normal driving there is no KR. Im thinking the PCM is just relearning still, but Im thinking about other ways to get rid of it instead of just driving it.
I run the SC 91 performance tune on 93 octane with OEM Champion plugs. Engine is all stock except for the CAI, TB, and the 2.5" dual cat-back exhaust. Should I replace my spark plugs to one range colder to avoid any knock? And to verify, that would be the Autolite 3923s?
I want to keep my new bored out TB, but I dont want KR reducing my timing during WOT. And while Im waiting to get the new plugs, is it a good idea to just remove the 91 tune, return it to stock or the 87 tune and still run 93 octane? Thanks for the help. Maybe Im just being over paranoid but Im pretty sure even a little KR should be avoided.

 

thats really what its there for, it allows for differences in the fuel from different fill-ups, basically allows the engine to run at the maximum possible timing, with out knocking, i wouldnt worrie abouit it to much unless you can hear it, and it will have KR really only on heavy throttle/load, its up to you, but i wouldnt worrie about it as long as its not actually knocking/pinging

 

Ive never heard what a knocking engine sounds like, all I know is it sounds like marbles in the engine or something like that. Would I notice it with the windows down?
I was watching my KR on the way home again, and under WOT it only goes to 1.5 degrees and I downshifted manually in to 2nd and floored it going about 40mph and it went up to 6.5 degrees for a second.
So what I gather is even though Im getting some KR, Im not damaging the engine? Thats my first concern, second is performance.

The disadvantage to a colder plug is having to swap them out more often right? Id be looking at changing plugs about every 20-25k?

 

you will hear it, its a tearible noise, but as long as it doesnt knock, you wont have damage, and it takes quite a bit to actually damage an engine, but as eric said, get some miles on it and see if it helps, then the plugs may clear it up more

 

Ok, thanks guys. I would hate to destroy my pistons (and whatever else) over a TB that wasnt even necessary.

 

Now I'm not sure about the Dak but on my Jeep whenever you reset the PCM it takes approximetly 50 starts for it to "relearn" what it needs to. And during that time you need to drive it "normal" because if you go racing around it's gonna think that is normal and set some screwed up perimeters.

 

Interesting. Thanks for that. I was wonder how far I needed to go. Ill drive normal from now on, I have 36 miles and havent been hard on it too much.

And btw, if you want to know how long its been since your last reset, theres an option in the data logging menu on the SC tuner that will allow you to see how many miles its been and how many engine warm ups there have been.

Im going to go pick up some Autolite 3923s this weekend. The colder plug should help avoid any pinging in the future if there will be any and reading some old threads alot of people just like them in general because they make the 4.7 idle smoother. For $15 and an hour of work Ill give it a try.

 

What in the world is a "KR"? sorry for my ignorance, but i don't have any performance mods or even a tuner(yet) for my truck!!!

 

knock retard, (timing retard) if the knock sensors sence any knocking/pinging, the computer will retard the timing as much as needed to keep it from knocking