Quote:
Originally Posted by rogerthechorister
That is useful info tx, but the lambda as tested is spot on (as I said) and the lambda light is off. I am therefore not suspecting the lambda sensor as such. Unless you can suggest why I should.
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The CO is far too high, indicating either a failed/failing Lambda sensor, the Lambda light is nothing more than an engine management light and won't come on until the Lambda sensor has completely failed.
The two first things to look at would be Lambda sensor output and cat condition. It may be possible to revive the cat with some Cataclean and an Italian tune-up but first make sure the Lambda sensor is actually giving the output it should or the ECU will be running the engine rich no matter how many air filters and sets of plugs etc you throw at it.
If the Lambda sensor is fine when tested as i described (given that it's running rich, it should be showing in excess of 0.5V - however i suspect it will be shoing less than that!), check the resistance of the CTS (it is separate from the gauge sensor, the CTS is between #2 and #3 inlet tracts on the head, just below the inlet manifold, the temp gauge sensor is nearer the 'stat housing) using the resistance range on your multimeter.
Each pin to a good earth point should give ~2500 Ohms +/- ~250 Ohms at 20C, on a hot engine it is significantly lower, can't remember the figure exactly but they're on the forum somewhere and i think are about 300 Ohms when up to temperature.
Also check pin to pin which should be the sum of the two pins to earth, about 5000 Ohms at 20C and 600 ish when hot.