I have a "map trim" knob as part of my instrument panel, i asked the original builder and he said its used to mess with the AFR qualities, well when i was on the dyno the tuner tried to adjust it, and there was no difference on the fuel map/AFR

Im assuming its not hooked up like a few other things, but its a simple turn knob, that rotates about 180 degrees left to right...Does any one use this, and if so what does it do?

 

what aem are you using? aem ems? or what?

 

It sounds like it is a linear poteniometer, that was probably hooked up and used with a fuel trim table just like a temperature sensor.

I have never seen anyone do this b/c if the O2 feedback, fuel table and fuel trims is set up properly you should never need it.

 

Im assuming its suppose to be hooked up to the AEM EMS 1052-u.......I called the builder and he said it was used to play with the AFR's..........I wonder if this was installed because of changes in altitude, etc...This was a formula D car at one point, and they travel quite a bit.....just a guess