Oxygen sensors

I have heard that O2 sensors can deteriate over time and start increasing
fuel consumption without triggering any alarms/waring lights. Does anyone
have any information or opinions on this?

Cheers

Mike

 

Well I have just developed an oxygen sensor problem on my Omega, at
least the blink codes suggest " oxygegn sensor no connection". Funnily
enough if I drive the car for a few miles, then stop and restart the
EML goes out.

The reason I mention this is when I'm motorway cruising with the EML
on, and the ECU presumably guessing the lamda, I return 40- 42 mpg -
engine temperature a couple of degrees above normal. Doing the same
thing after a stop start, so that the EML is out & the ECU 'happy', I
return 34 mpg.

This suggests to me :-
1) I need to replace my oxygen sensor - that looks like afun job
without a pit / ramps.
2) The sensor can give values quite along way from correct, hence
screwing my mpg, without activating the EML.

 

I would be inclined to check the connector
unplug it and make sure the terminals are not blackened
a quick squirt of switch cleaner (pref not wd40 if you can avoid it) might
be the cure

mike

 

Not a bad idea, I'll give it a go this weekend. On the whole, I am a bit
disappointed with the fuel figures for our 1.8 zaf. Its getting mid 30's on
a 50-55 mph run on cruise. Looked at all the usual, filters, tyres,
tracking, plugs etc. when we got it was even worse but was quickly sorted
due to a naffed thermostat not letting the engine warm up so was always
running rich. (cabin was bloody cold as well!).

At least if I change the o2 sensor its in a reasonable place, just on the
manifold, staring you (me) in the face when you lift the bonnet.

Mike

 

Why switch cleaner as opposed to WD40 - does WD40 do something nasty? - the
reason I ask is I use it all the time, but want to make sure I amnot
screwing things up ...

 

I'm wondering if it's cold weather related, my wife's 1.8 zaf (
complete with new foglamp bulbs....) seems to have dropped about 10% in
economy on a run; since the summer months. I'm sad enough to monitor
my Omega mpg long term, and it always seems to dip a few % in the
winter, even doing exactly the same commute.

 

wd40 is oil based and switch ceaner is solvent based oil burns when it gets
hot and puts a black film on the conecter.

 

Thats great, thanks - and the connector being where it is of course theres a
risk of the deposit forming and causing problems.

I spray pretty well everything that looks likely with WD40 under the bonnet
to avoid salt corrosion etc setting in (I do a lot of mway driving and the
salt really builds up under there), but I'll watch out for this one, thanks

 

I'm curious... I frequently see non-Mways being gritted and salted at this
time of year - bit scarcely ever see Mways being done. Is this a freak
experience, or are non-Mways actually a more significant source of corrosive
salts?

BTW - one of my justifications for never washing the car is that I don't
want nasty fresh salt making direct contact with anything metallic...

 

Well I dont wish to remove the highly complex chemical mix that comprises my
anti-dazzle coating.

Mike

 

Could be simply more fuel needed to get engine up to economic working
temperature.