Hi all, long time no post. I have been having an interesting thing going on ever since my V-AFC has been tuned. The tuner set my vtec at 5000rpm and set both hi and low to +3 between the 5 thru 7, zero at 8 and -3 at 9. The gains are great. But the issue now is partial throttle response between 5 and 6K. If i am between 5 and 6k rpm and not WOT, and especially if i'm lightly pressing the gas and decelerating slightly, the engine sputters and emits and almost backfiring sound gurgle similar to my WRX. I would have to suppose its cause the car is running richer there and i'm not at WOT. The car feels wierd like it loses a good amount of power until i drop under the 5k point or step on it. My question is what do you guys all think? Is this harmful to the engine? If it isn't, then I can deal with it, but I'd hate to be stressing the engine. If it is, then i'm seriously considering resetting it back to 6K vtec and tuning out the +3 between 5 and 6K.

Thanks guys!

 

Your V-TEC Low -> Hi is set at 5K, but what is your Hi -> Low set to? Just curious as you did not mention that.

 

curious if you have a dyno plot?

 

I believe you have the ability to offset/tune both WOT and POT settings. IMO and after reading alot about the VAFC, it would only be wise to tune the WOT Settings. If the tuner did not tune POT settings then I have no idea what wrong. If he did I would set all POT settings to zero.

Beroz

 

Check the percentage setting he has for your WOT and part throttle, he might have the WOT set too low. This would cause the WOT settings to be in effect while you are at part throttle.

bryan

 

As some have already stated, this car doesn't respond too well if the throttle position settings (Lo / Hi) are set too low OR if the narrow throttle fuel corrections are used. I had similar behavior from my V-AFC until I set all partial throttle fuel corrections to 0 and raised my Lo / Hi throttle settings to 80% / 81%. Basically, you don't want the V-AFC to do ANYTHING when the ECU is in closed loop mode.

It also seems like your VTEC engagement is set too low to be beneficial. Most NA applications only benefit from lowering the VTEC engagement to 5600-5700 RPMs. Setting it lower than this usually reduces power.

 

Whats your vtec correction value set at. With the vtec all the way down to 5000 rpm you should probably be somewhere around -12
maybe even -14. If your correction value for the vtec engagement is not right you will sputter.

 

He's blown.

 

I will investigate all settings and post them later tonite. Thanks for the initial feedback.

 

Did your tuner make adjustments while the car was on the dyno? Or was he just guesstemating