1997 lt1 355,1.6 rr,headers,36#inj,236/236 580/580 cam.i just bought autotap and i would like to know if my car is runninig lean or rich. what do i look at? i am not a computer guy. explain like you are talking to a dummy. i have GOT IT hooked up after several hours messing with the db9-usb software, and it covers a lot more things than my regular scanner. it works pretty nice. i bought it off ebay for 80.00, and i think it is the enhanced gm. since rebuild i am getting knock retard that's why i bought it so i can try to log it. i am runninig out the 93 octane gas and will try 100 octane to see if it resolves knock.

 

Take a look at what Injuneer has written up. It may answer some questions.

http://www.injuneer.com/ScanMast.html

 

You can not read the actual A/F ratio off a scanner, or scan software, such as AutoTap. You can find the PE Mode (let's call that "WOT" for simplification) "target" A/F ratio, but that's what the PCM is using for its calculations, not what the engine is actually operating at. Similarly, in closed loop, the long term fuel corrections will tell you what kind of corrections the PCM is making to hold the A/F ratio at the programmed 14.7:1 stoichiometric ratio, based on feedback from the O2 snesors. But that assumes the stock, narrow-band O2 sensors are functioning correctly, and are not being "fooled" by misfires, exhaust leaks, wiring problems, etc.

You have to use a wide-band O2 sensor/controller to determine the engine's actual A/F ratio.

 

this stuff is to complicated for me. i am going to take car and have a dyno tune. i have a mail order tune but i don't think car is right. i can do mechanical repairs, i rebuilt motor, but this ecm tune stuff is to much for me to learn on my own. even if i buy the jet obd2 software i won't know what to do with it.

 

"A man's got to know his limitations". Do whatever is right for you.

 

that's the way i see it to. time to get help. my wrenches can't solve this problem. but i am glad i bought the auto tap. it works very nice. it does as much as much as a very expensive scanner.