General Warning: Noob Tuning/Vent

[big_d]

Hello all, I'm getting frustrated with this car and I need to vent...Ok. First off I bought the car a couple months ago, and it ran very well...I just recently got my logger back up and running so I decided to pull a log...KNOCK!...so I decide to add some fuel on my maft gen2. I begin with the mainscale(which was set at -37) and gave it some more(moved to -31). The car has no knock...but my o2 voltages (I know i need a wideband...it's coming soon) seem lean(low .80's). So i go for another run and at high rpm it shudders(sometimes kicking)...so I'm thinking damn I screwed something up. All I did was try to fix a knocking problem and it responds like this? My mods are in profile, boost is at about 18-20lbs. I have not begun to touch the low, mid, and high settings on the maft. Help a noob tune! Races are Saturday! Thanks, big_d

 

[VETTE_50_TH]

How are your fuel trims. I've been taught to level your fuel trims and for every degree of knock, pull back your boost.

James

 

[big_d]

Low 110.9%, Mid 96.9%, High 99.2%...I pull back the boost but it still creeps to about 18 lbs...It just boggles me how it runs so well then I dick with 1 thing and it hurts...Does my main scale of -31% seem right. Thanks.

Sorry for the double post...but if I add fuel to the low trim will I have to carry that correction value throughout my other trims...For example, if I +10% to user low, do I use that as a starting point for user mid and user high? Thanks again, big_d

 

[spyderturbo007]

I've never tuned with a MAFT, but I can still help you out.

The trims aren't going to effect WOT tuning, so that isn't causing your problem when boosting. What injectors are you running? Your profile implies that you are still on the stock injectors, so why are you pulling out so much airflow? With stock injectors, your settings should be zeroed out or a little negative if you want to shoot for something other than the ECU's AFR target of 9.5:1.

Lo, Mid and High settings are for different airflow values at cruise / idle conditions. Mid and High values look fine, but the Lo settings are a little lean. At 110% on the lo, the ECU is adding fuel to compensate for a lean condition, so you'll need to add some fuel (i. e. remove airflow) with the MAFT. Anything within + / - 5% is fine when it comes to trims. So, anything between 95% and 105% is where you want to be with the trims.