Locked in A/F numbers

[tazgn]

Aloha,
Just wondering if anyone could tell me what's up with my FAST system? This started happening back in January before I left for a deployment. And I just noticed it's doing it again!! If I sit in the driveway and try some tuning with the FAST system, after a little bit the A/F ratio number will lock into some arbitrary number and not move no matter what I do. For example the indicated A/F ratio will lock into 14.44 today and not change even with the car off or driving around. My VEGO numbers are as follows when this happens.

VEGOR 2.47 (constant)
VEGO 2.21-2.29
VEGOS 0.47 (constant)

Anyone have any ideas? It just happens at random times, and the car still seems to run OK.

Derrick

 

[bobc455]

If you disconnect communication then reconnect, does it still show the same value? What if you reboot?

-Bob Cunningham

 

[tazgn]

Yep,
I've rebooted, disconnected and reconnected, and even turned the car off. If I turn the car off and restart it and reconnect the computer it will come up with a different locked in A/F number (random number). This only happens every so often. Right now I could go out and connect the laptop and it wouold probably work fine.

Derrick

 

[Craig Smith]

If the UEGO value is fluctuating, I don't understand how the a/f ratio could be steady. The displayed a/f ratio is actually derived from the UEGO value. Since I've already assigned too much blame on cosmic rays for these sorts of problems, I'll have to blame El Nino for this one.

Can you make a data log showing the voltages you described above with a perfectly steady a/f ratio?