Wits end CO Emissions

[cavalier1990]

Yes Robsey variuos back boxes do have a little hole at the bottom of the silencer, usually forward facing or at lowest point of box to drain water. Of course any extra air in exhaust is not unmetered air, bit will affect lambda readings, as that basically measures oxgen content. I think the theory is too much oxgen is an emissions problem i.e. means incomplete or poor combustion.

[cavalier1990]

I have had a car with a purposed hole in the silencer box to disperse condensate but I seem to remember the first place it started to corrode was from the hole!
Not really sure if it's a good idea.

59.9mpg, that's brilliant! Best I have achieved was 54.

Alan

I drilled one on my granada back box and about half a gallon of water came out. The back box is still ok, it's a bosal one and been on it since 2001!

It was a good mpg alright, just shows a gutsy old 2 litre probably better than most of the anematronic cars on the road today!

[Robsey]

Strange phenomenon occurred today.

Whilst waiting to use the free air machine at Sainsbury's to check my tyre pressures, I noticed my idling figure drop down to 0.3%
About as good as it ever showed on the trip computer.

So I am hoping that something is happening to rectify my car's mystery fuelling as a reward for my many hours of lost blood, sweat, sleep and tears.

Just hope it continues to improve...

[Mk3alan]

A self healing Cavalier, you could be onto something there!
I wonder if it might be worth temporarily replacing the temp sensor with a potentiometer so so can simulate cold and hot running and see what happens to consumption figures?
Just a thought if you were bored.

Alan

[Robsey]

The temp sensors for both ECU and gauge were replaced a few weeks ago.

Made no difference at all.

I plan to do my cam-cover gasket at the weekend, so I will give all the breather hoses a good clean whilst I am at it.

A further plan is to strip out the whole ECU / injector loom and check every wire for continuity and condition.

[cavalier1990]

Something else I noticed on the car last night, and I don't know how this got to be, but the octane plug was set to 91 not the 95 setting. Very odd as I distinctly remember checking this before and it was where it should be, and I wouldn't have put it to the 91 setting (would I!) maybe I had a senior moment or out of desperation an forgot to switch it back.