Predator help needed... Started logging today.. getting KNK LT and ST
Ok.. running the 87 tune on 87 octane fuel.. Only mods to the truck are dual in, dual out magnaflow exhaust and an airaid CAI.
I used the canned 87 tune with the exception of disabling MDS.
Now... I've done several WOT take-offs to 75-80mph or so and also drove around normally. Here's what I've collected:
Worst KNK readings during Normal Driving...
0.50 KNK ST @ 1748 RPMS
1.0 KNK ST @ 1809 RPMS
Never got KNK LT during normal accelerations.
Worst KNK readings during WOT runs to 75-80MPH (I did 3 of these but they were all close to the same #'s):
5.0 KNK ST @ 3676 RPMS
1.0 KNK LT @ 4274
5.50 KNK ST & 1.0 KNK LT @ 4410 RPMS
I understand knk lt to be bad?... so what changes should I make? Or should I just change fuel or what? This is BP 87 octane fuel.
you don't have a wideband do you? curious what your wot air/fuel ratio is?
I'm assuming higher octane gas couldn't hurt but I'd really like to adjust to correct the issue as is rather than changing fuel. Where should I start?
Any additional pids to log that'd be more helpful?
Im not sure about the 4th gens but I know on third gens 89 octain is recommended even if using the 87 tune. Maybe that is the problem?
Contact Johan at Diablosport, you can find him on their forums..
I sent him my last tune and some datalogs and he sent me a tune that really woke my truck up.. He also noticed that my intake temps are constantly pretty high, even while driving normal speed :-( which will affect performance...
Thanks.. I sent him an email.. Hopefully I'll get it resolved. Back to factory default for now.
If you don't mind me asking, what'd you pay for the custom tune?
Johan hooked me up for free.. It was one that he has been sending to alot of people that mainly changed the shifting parameters.. If he had to go through all of the data logging and really modify the tune I'm sure I would be charged. He said that if all that is done is a CAI, Exhaust etc, then usually a full custom tune is not needed.
I have gotten knock on myu 2010 stock.
Sometimes up to 3.5.ST knock.
But its almost always due to lugging of the motor,or when you floor it at a low RPM.
ST knock is nothing to worry about because it does not pull timing.
LT knock is pulling timing so thats not a good thing and is not normal.
If you floor it you should see a spike in ST knock,but then it should go down and stay down,except possible at shift points.
If your ST knock keeps increasing with a increase in RPM then you have a problem.
A exhaust change can be the cause,especially if you dont use all the original exhaust hangers.
Also cheap cutouts seem to make some knock.
Sometimes a coil,or bad plug will show up as a miss,which will give you some knock.So datlog each cyclinder to look for a miss.
My bet is on your exhaus:clamped exhaust,not using rubber hangers.???
The exhaust touching the frame will for sure cause knock.
My ST #'s only go up when flooring it and when it shifts and right before going in or out of MDS (if enabled).
The LT #'s go to 1.0-2.0 under load at 3500rpms or higher if I'm giving it gas with the 87 tune running either 87 or 89 octane gas.
I filled up with 89 octane and have now driven 100+ miles on it and the 87 tune still causes 1.0-2.0 LT KNK where the factory tune shows zero.
The highest ST KNK I've seen with the factory tune is 4.0 flooring it at low rpm.
Seen up to 6.0 with the 87 tune on ST KNK (running 89 octane fuel)
My ST KNK #'s do *NOT* seem to rise with RPM.. they seem to just jump at WOT, shifts and MDS going in/out. Then then within 2-3 seconds are back at zero.
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