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[Sixstring]

Has anybody heard of, tried, or  know its NOT any good fix for the problem Di and many others have with the lambda sensors causing the EML light to come on bby soldering resistors across the feed wiring to "fool" the ECU into thinking all is well?

Have had a few conversations regarding this with VX employees, and wondered if it was heard of, or dismissed as no good. IF its ok, will make a load of these and hopefully will fix Di and others for free!!!

Comments please.

Mike.

[Jimbob]

Hmm, not sure exactly how the lambda readings are used by the ECU, But im guessing a fixed resistance, plus normal readings could well affect the cars running and fuel consumption.

[Sixstring]

Yes, Jim......I thought that, too.
BUT....the lambda must have some sort of running tolerance resistance, so if you can find a resistance midway, theoretically you can fool the ECU into thinking all is "normal" and just ignore the sensor.
That being the case, the EML will stay off for that problem??

Good thought, though.

Mike.

[Kevin Wood]

The Lambda sensor is not a simple resistance, though. It generates a small voltage based on the proportion of oxygen in the exhaust gases.

The engine ECU is constantly cycling the mixture on each bank between lightly rich and slightly lean, which leads to the output of the (pre-cat) Lambda sensors following the changes in mixture and cycling from about 0-0.1 volts and 0.8-1.0 volts.

When the pre-cats are not working the output of the post-cat lambda sensors follows this pattern as well.

As the pre-cats start to work, the cats absorb oxygen when the mixture is lean, and use it to break down pollutants in the exhaust gas. They eventually reach saturation and oxygen appears at the post-cat sensor. When the mixture goes rich, the cats liberate oxygen and continue to break down pollutants until they eventually are exhausted.

So, the pattern that the ECU is looking for is an increasing delay between the pre-cat sensors indicating "lean" and the post cat sensors indicating "lean" as the cats start working.

A simple substitution of a resistor won't work, but I have heard that crudely delaying the signal using an RC circuit or even by spacing the Lambda sensor away from the exhaust using a spark plug extender can solve the problem.

I have never tried the above, though.

Kevin