check the gauge connection to the lambda signal is ok and that the power and grounds are good.
If ok it is likley to be a faulty lambda sensor. When warm the sensor should rock between 0.3 and 0.6 volts. This is equal to stoich.
You will probably find it is stuck around 0.2 volts.
The ECU is trying to maintain an AFR of 14.7 / Lambda 1. This is why it rocks too and fro. too rich and the ecu removes fuel, too lean and it adds fuel.
Once you go above approx 3200rpm or achieve greater then 0bar boost i.e no longer a vacum, the ECU switches from using the Labmda sensor and 14.7AFR to using the MAF. Fuelling at the top end on a stock WRX would be around 10.5AFR
These AFR gauges are only for peace of mind, they should not be relied on or mapped with, as the sensor in the car is only a narrow band.
Last edited by Scott.T; 19-05-2010 at 05:41 PM.
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