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?
--
Andrew Stephenson

"Andrew Stephenson" <ames@deltrak.demon.co.uk> wrote in message
news:1172704321snz@deltrak.demon.co.uk...
> 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?
> --
> Andrew Stephenson
>

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!
--

Ray O
(correct punctuation to reply)

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, ...
--
Andrew Stephenson

In article <1172793854snz@deltrak.demon.co.uk>
ames@deltrak.demon.co.uk "Andrew Stephenson" writes:

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

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.
--
Andrew Stephenson