Guys I'm worried about my partial throttle knk and F/A Ratio

[lross78550]

Guys PLEASE a little more help. I know I am a Pain in the As*.
I think I have the st and lt knk set right for WOT (check my latest log and you tell me). However when i do a partial throttle run the ST knk goes as high as 6.5 (usually 5 is the highest it goes) the LT knk goes up to 3. Also the Fuel / Air Mixture at about 43% (76% is WOT) gets as lean as 14.7 this also appears to be when the ST knk retard really kicks in. I am currently running the stock 93 oct timing settings with 93 oct fuel. In the mixture settings I am set to +10% (1-3.8k) +12% (4-5k) and +10% (5-7k).

The first 23 seconds of this run are at WOT the rest of the run is at different throttle settings.

Is the partial throttle knock and fuel / air mixture a dangerous condition as its running right now and if so what should i do about it? My only options are the 89 oct tune and the 93 oct. I doubt i can find better fuel than I am running. I would prefer not to retard timing unless running the current settings long term would be dangerous to the health of the engine.

Run #5 is the latest run that includes the partial throttle run.

Thanks again for the help and I will try to make this my last question.
Lee

[HerDaytona]

Good going, are you running lower fan settings??? Might want to go that direction. Also the catch can can't hurt. No good gas stations around??? Good luck still have the LT Knock goin on. Plenty of room. Running the 89 with the best fuel and fan settings and then adding the fuel could get you there.

[09SuperBee]

add more fuel to get rid of the knock. Start adding a little at a time and run logs until you see it go away, or get down a lot from what you currently have. I have seen people add as much as 20% to the fuel, so you are on your way. It took me a month or so to get it adjusted to get rid of the knock, but once I did, it's running great with little to no knock. Good lick

[Quick]

The tunes/tuner do not adjust partial throttle fuel. Only open loop.

[lross78550]

The tunes/tuner do not adjust partial throttle fuel. Only open loop.

So Quick if the log looks good on WOT runs but you have ST knk retard of 5 on partial throttle runs and if the f/a ratio is fine on WOT runs but is as lean at 14.7 on partial throttle runs is that dangerous to the motor?
Thanks
LRoss

[06MonteSS]

14.7 is the stoich AFR at part-throttle... it will always be 14.7 at part-throttle... that's what it's supposed to be and is normal...

no worries...

[Quick]

What he said ^^^^

14.7 is the ratio most efficient for gas (all the oxygen and all the fuel is burned). almost -- it's actually a little bit rich since the catalytic converters need a bit of fuel to touch off the reaction there. At partial throttle you're in closed loop operation -- the PCM is monitoring the narrowband sensors and constantly adjusting the fuel towards 14.7. It does that by constantly running the fuel from one end of the narrowband's range to the other (roughly 13.8 to 15.3 or something like that). For power you need more fuel. That comes from the Power Enrichment table. At WOT you're in open loop operation and the PCM is applying a fixed amount of additional fuel to whatever you were running just before going WOT. It's that additional amount of fuel that you're adjusting with the Predator.

Log with the stock tune and I expect you'll see very much the same at part throttle. You do know that if you scroll all the way down in the perf tune menu you should see something like "modify stock tune" or something like that? If you select that tune you can apply the stock tune without resetting the predator and all that. Actually you might want to "reset parameters" if you do that so you'll have the unmodified stock tune. Here's something you'll probably want to learn anyway:

Get your tune where you want it (probably there now right?).
Go through your parameter list and write down each parameter you've changed and the value.
Upload the "last written tune" to your PC (might want to rename it something meaningful). Stick it in a folder with a text file of the changes you just wrote down.
Download that tune back to the Predator. It will show up in the Custom Tune menu.
Now you can switch back and forth between the stock tune (or any other one) and that one without re-doing the parameters every time..

[lross78550]

to 06monteSS and Quick: Thanks a ton guys the truck is running like a scalded dog and now that i know i shouldnt hurt anything im going to take Quick's recommendation and save my settings as a custom tune. I really apprieciate your help and finally feel like i have at least a novice's understanding of how to use the predator now.
LRoss78550

[FAhemiST]

unless you have a wideband a/f gauge, you cant tell what your a/f ratio is at wot

[lross78550]

unless you have a wideband a/f gauge, you cant tell what your a/f ratio is at wot

When data logging with the the predator one of the data sets is "A/F Ratio". When I add fuel with the predator this number gets lower on a WOT run. When I lean the settings with the predator this number gets higher on a WOT run. Is this not my A/F Ratio at WOT? If not why?
Thanks
LRoss78550

[Quick]

It's "commanded" a/f. The PCM takes the fuel values from the tables (and other things) or what it calculates and figures this would be the resulting a/f. It's a calculated value that is based on everything being stock (especially physically) and not a measured value. Add or remove fuel with the Predator and you change the values in the PE table. These values are part of the calculation and your changes will be reflected in the result.

If, for example, you added a CAI with different flow characteristics then the calculated A/F might differ from a measured A/F. The car takes barometric pressure at startup using the MAP sensor. If a front blows in while you're driving the car and the barometric pressure changes then the calculated A/F might differ from the measured A/F. For a basically stock car it's probably going to be in the ball park but it could differ (how much, I don't know).

[butch1581]

So on his runs in the log, is it ok to have the KNK LT RETARD or the KNK ST RETARD register like his is? I thought you wanted both of those to remain at "0" all the time? I would like to log a run tomorrow to see where I am at too..

Thanks

[Quick]

...basically...

LT should be at zero all the time
ST might bump to 2.5 or 3 at the shift points and go to zero quickly.

[butch1581]

Thanks for the info. I am going to see where mine is at and add fuel if needed. I assume if there is no KNK then you can remove fuel until there is a small amount then add the fuel to get rid of it. You want to be right on the edge correct?

[Cruisin1966]

Sure, if you want to go to that level, you have the procedure down. Remember, this is ONLY at WOT using the handheld, unless you have access to someone with the CMR software.