Hi all. I have 87 Firebird with 305 carb engine. My problem is that I have OTC scanner that shows NO Codes but when I run the test or try to read any data it works fine sending data in open loop mode. As soon as it warm up enough to go into closed loop I lose all data, no rpm nothing. It just says no data. I have tried this with 2 OTC scanners and many times. It just warms up and then I get the no data on screen. I have all the data and can see rpm and as soon as it should go into closed loop I lose it all.
Any suggestions.