So, I had this project done and tune for about 8 months now, every now and then some issues pop up like any other project, this time I’m not sure what’s going on, car was tuned to 775whp on 91 oct and Wmi, I was doin some E20 tuning to start using ethanol during the hot days, I was able to get it up to 53.5 psi on map reading and 25 spark advance. Let the car sit for a couple of days while I was working on another project, did a test run and the car goes super lean, set boost to 0, only spring pressure and still lean, looking at logs the rail pressure stays the same 43.5psi, so no rail pressure drop while going lean, decided to take out the E20 blend out the gas tank and added normal 91 pct fuel and took injectors to have them checked and cleaned and the came back up to specifications, so set timing to 10 and still running spring pressure with 91 octane car still goes super lean under boost and only under boost, I can set VE table up to 150 and still have the same result, injector pulse with goes thru the roof, so I don’t understand what maybe causing this issue, bad map sensor?
Any suggestions on what to look for or check?