Warwick <usenet@affordable-afpers.co.uk> wrote:
> In article <1glk6pz.1wgaragj3pmdbN%hairy.biker@spamcop.net>,
> hairy.biker@spamcop.net says...
> > Paul Giverin <paul@giverin.co.uk> wrote:
> >
> > > Is it possible to make a judgement on the serviceability and condition
> > > of the lambda probe by using the emissions test report from a recent
> > > MOT?
> >
> > Probably not, unless you can totally isolate any other causes of
> > emissions anomolies. So many other factors can affect such a reading:
> >
> > condition of the air filter
> > condition of the spark plugs
> > quality of fuel
> > engine wear
> > engine problems - such as valves sticking on a Zetec
> > the calibration of the individual test machine - they can vary very
> > slightly
>
> The Escort had trouble getting a pass on the emissions a couple of years
> ago. I changed all of the filters, the garage replaced the cat and the
> last thing changed was the lambda sensor (which turned out to be the
> fault). It seems they aren't very prone to fault and there are so many
> more basic things that'll go wrong that its well down the list of
> diagnostics.
Indeed. I went on a Ford trainign course a few years ago, and the
instructor told us that he'd been given the task of testing some 3000
Lambda sensors that had been returned as warranty repairs. Only one was
actually faulty.
It should be very low down on the list of possibilities. However, you
should also look at other information too, such as likely causes on a
particular vehicle.
later Escorts, for example, had the block connector mounted upside down
behind the radiator. As such they were prone to filling with water.
Simply drsining the water and cleaning the contacts was enough to effect
a repair.
On a Fiat, you could quite easily suspect the sensor in the first
instance.
> If assuming there was a reason for the question and the only one I can
> imagine is that fuel economy is down.
>
> If his emissions are a pass and fuel economy is down then it isn't
> likely to be the lambda. An air leak somewhere would do it though.
Doubt that, an air leak is likely to cause poor emissions too.
> Just pondering
There's plenty of food for thought here ;-)
--
Andy Hewitt ** FAF#1, (Ex-OSOS#5) - FJ1200 ABS
Honda Civic 16v: Windows free zone (Mac G5 Dual Processor)
http://www.thehewitts.plus.com