Thread: Spanner size
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Old 20-04-2016, 06:34 PM
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Scott.T Scott.T is offline
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Originally Posted by scotty View Post
Mmmmm well the sensor is not budging but on another note not sure if its helped but we know the car needs mapped but un plugged the sensor and its seems to improve it but we see tomorrow when driving to work lol .
If you unplug the lambda the fuelling will run off the base map which will be close to where it needs to be (14.7 AFR at idle), but probably not quite tight enough control for an MOT.
Failing lambda normally give a duff low reading which cause idle and cruise to run rich at about 12AFR.

Unplugged is fine in this instance, and they don't tend to log a fault unless you force a diagnostic test.

The lambda is only used at idle and cruise (approx less than around 3500rpn and negative boost/vacum).
MAF controlled fuelling is used beyond that point.
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