I have a 1993 Z28 that I just got dyno tuned by ION. It runs awesome now becuase it is tuned correctly for WOT. However, I get a very rich mixture at idle. I have a CC306 on a 93 motor with LE heads. My map sensor voltage at idle is about 3.79 Volts and the counts are at 1 in closed loop. I get a code thrown every once in a while for map sensor voltage high vacuum low. I am thinking this is due to the cam and did a search with nothing helpful found. I have a vacuum canister for the brakes becuase they won't work very well. Has anyone had this problem? Or have a fix? All the vacuum lines are basically new.

 

By counts what do you mean? Iac or INT?

You might have to get Ion to clean up some of the part throttle stuff. ON the larger cams if they chug rich for too long they will set a low engine vaccum light.

Really that 306 isn't that big of a cam. i've gotten 93's to work on 255/260 cams.. race cars though

 

im just getting into superchargers i have a 93 also im putting a 5psi vortec in tomorrow / new racetronic fuel pump and 37lb injectors what should i tune on my chip for start up /i also have a chip burner to burn 93 chips

 

We haven't had a chance to do much part throttle tuning last time since it was pretty busy, but I'm pretty sure I'll be in the area this Saturday so we can tweak the part throttle stuff. I'll keep you updated.