FAST old gray box software

[Jim Whitehead]

Originally Posted by mike britt

So FAST is telling me this thing will never run right without an O2 reading. I thought if you ran it in open loop, which I thought everybody did, it wouldn't matter if it gets an O2 signal or not.

Mike the engine will run fine without a O2 in open loop, however you are shooting in the dark on your A/F ratio.
Question. Have you tried making a pass with the O2 in it, or is this a new setup and you are just trying it while running the engine. If the O2 is way back in the collector and you are not at full throttle you will not get a reading.
I took a gray box out of my car because the O2 stopped reading and the logger failed. It may be more beneficial to purchase a used Fast 2.0. They are very good and usually on the market at a reasonable price.