SunsetOrangeZ

iTrader: (10)

Ok so here is the deal, I know that the computer can't "LOSE" the tune but if sure seems like it with my car.

Here's the scenario...
Car was tuned near perfect on 93 octane, idled fine, no surging, 12.8 AFR at WOT.

I bought a nitrous kit, I was advised to put race gas in it when I spray it, filled her up with some torco 110, car still ran fine, it was just a little fat at WOT at about 11.5 at the high rpm. Sprayed it everything was god. So I ran that out, towards the end of the tank the car started running REALLY shitty. Stalling, surging, misfiring, hesitating. So the first thing I checked was the plugs. The passenger side bank was actually running fine, the drivers side was completly carboned up, plugs were solid black. So I check the o2 sensor, and from the shaking of the engine one of the wires of the sensor rubbed the heat shield so much it cut right through the wires.

So basically I have put a new o2 in the drivers side, put all new plugs in it, car runs good, but it is fat as hell. I'm talking 10.1 AFR, and all the race gas has to be gone I have gone through 3 fill ups with 93. So could running the 110 in it one tank change the commanded AFR. Now I don't drive the car too much, and I did change the MAF from stock to the slp 85mm one and didn't have it tuned for that, but the AFR was never this fat before. And I have reset the computer since all the race gas was out hoping that the fuel trims adjust themselves. Anybody have an experience like this?

Dart heads, 24x/24x cam, 42lb injectors, stock tb, stock intake.

SStolen

iTrader: (22)

Happened to me last year. I never figured it out (so I hope you do). I'm thinking my PCM might be bad or I had a bad ground. I'll find out in about another month when I start up the new motor and APS kit.

BTW, I had two tuners look at it and they couldn't figure it out. They pulled fuel at idle and nothing. They changed the injector size on the tune to 'trick' it and nothing. That's why I think my PCM is bad. WOT and cruise was perfect though. It was only at idle. Good luck bro!

LS1-450

iTrader: (33)

Isn't 110 leaded fuel? Our race fuel (unleaded) is only rated up to 100 octane. Perhaps this is what has LEAD (no pun intended) to the fouled plugs.

My guess is that the MAF tables need to be tuned for the 85mm MAF. Sounds like your STFT & LTFT's are dumping gobs of fuel in an effort to adjust to an airflow that differs from the measured MAF frequency. I'd also have a look @ your Wide band O2 sensor to see if it has been gobbed up.

stevegrizzle

My guess is the W/b is mucked up from the leaded fuel. Get another wideband on there to test before you go too crazy.

AVB

iTrader: (9)

Check connection to IAT.. reseat.

Frost

iTrader: (45)

The NBs are more likely toasted from the lead than the WB (though they foul quickly too) and their incorrect reporting is screwing up the cars fueling while in closed loop.

SunsetOrangeZ

iTrader: (10)

Great info guys, thanks for the input. I borrowed a MAFT from a buddy, I am gonna see if this helps at all, before I go an have it re-tuned.

Can I ""clean so to speak my wideband, and if so what should I use? Carb choke cleaner?/brake clean?

LS1-450

iTrader: (33)

My experience has been that once an O2 sensor is done, it's done; ceaning never helped mine. I agree w/ all of the comments related to confirming the correct operation of both narrow band sensors, wide band, injectors for that matter, & anything else that may have been in contact w/ the leaded fuel, is operating correctly before modifying the MAF settings or any other tune related change.

RickyMartinZ28

iTrader: (5)

I've cleaned a few with success using carb or electronics cleaner.... doesn't mean that it works all the time, but I have seen it done.

-Rick

stevegrizzle

Would you say that he's living la vida loca?


Ok sorry I just had to. Carry on

Frost

iTrader: (45)

Did you read the post I made just above yours? Why would you try and jack the tuning around rather than look at the issue? Or was that your way of implying that the fuel you used wasn't leaded?

gold98Z28

iTrader: (7)

a 75shot always worked good for me.......... stay away from leaded race gas, if you are running closed loop. if you want to run it, then get your car tunned in open loop. and if you didnt run your tank real low befor putting gas in it then do so. race gas has a differant specific gravity than pump gas and seems to not mix up good and leave some in the tank for a long time. i know after running it, i can still smell it in the exhaust for a long time, even after filling up with 93 again.

SunsetOrangeZ

iTrader: (10)

Yeah the gas was leaded. I am not using leaded ever again..
I replaced the bank 1 O2 sensor. That was the side that was all jacked. When I pulled the plugs initally, the drivers side was fouled, but the passenger side was perfect.

I monitored my STFT's and LTFT's today and Bank one is -20%(STFT) at idle even after I put the new O2 in. Bank 2 is around 3% but stays around 0%. But driving around and part throttle they seem to stay within 5% both ways. It is just fat at idle and WOT. Is it possible for the car to "load up" at idle and that is why the computer is trying to compensate? And why would it only be bank 1 that is going fat?
Bank 1 is the drivers side right?

Frost

iTrader: (45)

Yeah B1 is the driver's side. Why not try swapping sensors left to right on the front so that you can rule out the sensor from the equation.

gold98Z28

iTrader: (7)

thats what i was typing, haha, switch them and see if the trims follow.......

SStolen

iTrader: (22)

So what happened? Did you figure it out yet?