Car Dies

**kfish** · 11-25-2009

So after the headers, the car ran great. But here lately after i get into boost itll die. Usually i unplugged the MAF and itll fire right back up. So I swapped it out with another one i had laying around. Still did it, so i thought maybe it was just another junk one i threw in. So i pulled one off a car that ran great, and I had no problems with it until about an hour ago when it did the same thing. I'm clueless. When it dies i get a CEL and the scanner comes back with MAF/VAF circuit high input, and System too lean bank one. Any ideas?

**CityStarz** · 11-25-2009

high input could be open wire on the return circuit or lean 171 could be from a vac leak. do a good visual, make sure you didn't pinch any wires or pull off any vac lines

most likely the codes are related but it's hard to say which one is causing the other one. do you have a scantool to monitor MAF, O2 etc? lean is triggered when the upstream O2 is showing an abudance of oxygen in the exhaust stream and the pcm cannot add enough fuel to overcome the lean condition

i believe high input would be triggered when maf is showing a higher than expected value. MAF and throttle position should mirror each other, meaning when one goes up so should the other and vice versa. the pcm knows this and looks for a correlation between the 2 sensors, when one is doing something unexpected (like shorting out) it can tell that's not a normal conditon and set a dtc

**kfish** · 11-26-2009

just scanned again. maf g/s goes up steadily with the tps angle. i did check for vacuum leaks but ran out of carb clean lol. but i didnt find anything. it goes sound like a sucking noise around the base of the sc, but i could also be hearing the injectors.