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Contaminated fuel and O2/lambda sensors

This is going to seem OT at first; but stay with me.

UK supermarket chain Tesco today (28feb07) was reported as having sold, via its associated filling stations, petrol containing some kind of contaminant, nature so far unidentified. This has led to cars up and down the UK having running problems, traced to the O2 (aka lambda) sensor becoming coated by a varnish-like substance.

So many cars have been needing replacement sensors, that supplies have been running low in places. However, one garage, which does unusual specialist work, has found a temporary fix for some cars.

They put the removed sensors into an ultrasonic bath, which did a good enough job of removing the mystery gunk to allow the cars to continue using the compromised sensors. The garage's chief tech, interviewed on BBC-tv, guessed it would be wise to replace the O2 sensor soon; but said it worked pretty well as a stop-gap.

An idea for those (many) in this NG who report O2 sensor trouble?

Reply to
Andrew Stephenson
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During a search of engine-related TSB's for the U.S., I've noticed that the titles of several refer to a replacement ECU to solve frequent O2 sensor-related trouble codes. I suppose that contaminated fuel doesn't help much!

Reply to
Ray O

Certainly an option depending on what the contaminant is. Mind you people are claiming the contamination is causing their car to "stall and misfire". Now ive run a few cars with the 02 sensor pulled and they didnt drive brilliantly but they still worked well enough for "normal" drivers and passengers to not notice it.

Some people are claiming its ethanol - if it was ethanol it wouldnt damage an 02 sensor so id suspect its nothing to do with that.

J __________________________________________

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Reply to
Coyoteboy

FYI: an update on the Mystery of the Car-Choking Fuel...

TV news is reporting, with pictures, a possible explanation for the cars that have been conking out after being fed fuel from a range (not just Tesco but Morrisons and other supermarkets too) of el cheapo retailers. It seems those places send the tankers down to a facility by the Thames Estuary, where they load up on petrol sourced from You-Name-It. Even better, once loaded into the tanker it is common for additives to be chucked in as well, to bring the mix to whatever spec each retailer wants.

One popular additive is being called "silicone" (after a period of journalistic confusion between that and "silicon") which, it seems, is used to control foaming. An excess produces a crusty white deposit when burned (eg in a hot engine innards) -- which naturally works wonders for any car's O2 sensor performance.

The investigation proceeds apace. News at 11, 12, 1, 2, 3, ...

Reply to
Andrew Stephenson

Again FYI: another update: at the depot, from which the el cheapo outlets draw their petrol supplies, four tanks have been found to contain unusually high levels of what the media are still calling "silicon" (though it seems as if that should be "silicone", which eventually burns to form silicon dioxide, SiO2, a major component of most sands, as well as common glass). Now filling stations up and down the land are having to empty their petrol storage tanks, clean them well -- and decide what to do about a collossal volume of tainted fuel. Then there are those hundreds of cars with duff engines. Interesting times. (Can we UKians interest anyone in a job lot of el cheapo petrol? You can call it "gas" if you like.)

BTW for the tech-heads amongst us: it appears "silicone" is added to diesel, but not petrol. Evidently diesel engines can take it, even need it at times. Does diesel tend to foam? That's the job the additive is said to do.

Reply to
Andrew Stephenson

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