CptnObviousFC

ok i have searched everywhere on this forum i can think of and even looked at the write ups in the engine management section for the safc, but i cant find anything on this problem at all.
I installed my Safc-II on my 86 GXL, still running stock injectors, and started tuning a little bit, im pretty familiar with how to tune an safc as i had one on my 97 eclipse before i sold it. I set it for 98% low throttle 99% high throttle since the tps is more like an on off switch being an s4. Flap door sensor type 5in 5out 4cyl with arrow point up and to the right. The problem comes when i am tuning my fuel curves. if i try to remove fuel, it adds fuel, and if i try to add fuel it leans out...its like the fuel curves are working backwards...has anyone else had this problem before? Untill i figure this out i have left the afc at 0% correction. I have installed it as a precursor to turboing my N/A engine and i want to be sure i will be able to correctly tune it after i put in the turbo. The only other factor i can think of is that i am running an Autometer air fuel guage to a stock o2 sensor for my fuel mixture. I know this can be a little unreliable but even despite the reading of the guage i can tell the safc is tuning incorrectly.

Any help would be awesome as i am quite stumpped.

Rx7TyreBurna

iTrader: (1)

I wouldn't even consider using the stock O2 sensor for tuning even general tuning. When was the last time you replaced your O2 sensor?

I also have a narrowband O2 sensor (replaced with new bosch unit), and a pretty nice A/F gauge. Tuning my SAFC on the narrowband was useless, so a friend of mine had a wideband that you stick in the tailpipe and we used that.

I also noticed on my old O2 sensor, that when idling, it would say hardly anything, and then when I would floor it, it would say rich. Even though I had -10% to -15% on my SAFC. Then when I would let go of the gas pedal, it would go super lean, so lean it showed no bars.

Go to a dyno, or spend a little cash on an AEM UEGO, or something like that. I think they are only $150 or so, maybe more.

Richter12x2

iTrader: (1)

Innovate LC1's are in that ballpark, and have a built in narrowband simulator so you can use it to replace your stock o2 sensor, you will need to buy a gauge or hook it up to a laptop to read it, though.

On the tuning - are you sure you're in open loop? I would wonder if the SAFC and the ECU were fighting.

mazda13B88

would the super afc and the ecu fight each other?

Richter12x2

iTrader: (1)

AFC adjusts the air flow reading to the ECU, so it works with the ECU for tuning purposes.

mazda13B88

so their is no way of them canceling out each other then

Richter12x2

iTrader: (1)

Not according to the operation according to the Mazda service manual. The only thing that I would have thought might be an issue is the factory computer trying to lean to match the O2 sensor to perfect, but according to the service manual, the o2 sensor doesn't factor into fuel calculations, just the MAF, which is what you're adjusting with the SAFC