AF Ratio going out of range lean

[jleilich]

I was driving back from a weekend car show and noticed my AF ratio went lean out of range. The sensor seems to operate properly as it reads ok before start up but then goes all the way out of range once the car is started. Not sure whats up or where to look. It was working fine on the way down to the show on Thursday so something happened?

Here is a log of the car starting also of note, the idle is odd, it will idle but keeps dropping in RPM then returning to the previous RPM. This log included as well.

[hobieboy]

Didi you do some easy checks like power to the WBO2 sensor after engine is running?
Have you tried richening up idle area VE? Does it move the AFR reading at all?

[whittlebeast]

Looks like your alternator died. Look at the Batt V.

[jleilich]

I was fooling with it yesterday and as I was letting off the gas a few times the AFR would go back to a reasonable level on occasion. Unfortunately I wasnt running a log at the time. I may try to replicate it again and get a log.

[mlynch]

Just curious, I notice that you have not Selected or Calibrated your EGO Sensor in the "CALIBRATE AFR TABLE" Menu. I believe that you have got to specify the type of sensor that you are using and calibrate accordingly, before you will get usable EGO readings.

[billr]

The OP has selected WB in the Fuel menu, and I think the cals are always "lost" to TS once written to the ECU and TS closed. (My project never comes up with the WB cal in TS when the project is re-opened.)

[mlynch]

The OP has selected WB in the Fuel menu, and I think the cals are always "lost" to TS once written to the ECU and TS closed. (My project never comes up with the WB cal in TS when the project is re-opened.)

Billr, OK, that makes sense. It just looked strange.

[billr]

I encourage so to continue pointing out things that "look strange". That's how you (and I) learn. Sometimes such an observation, even though it may be in error, triggers thinking or discussion that does solve a real problem.