1995 164TS running very lean - or maybe not? Long post for the experts

[AR67202]

so you would stil get those crazy readings if you measured now?

I suppose a scope would be best to tackle these things... or at the very least a true rms meter...

[marco.marletta]

Yes, I still get those crazy readings now, if I provoke really rapid voltage changes,
say by suddenly releasing a heavy load on the engine. You're right, I should invest
in some better diagnostic equipment. It seems that anyone who wants to keep
a car with electronic engine management into old age without spending $$$$ on
garage bills probably needs to do that.

The differences now are:

* O2 sensor voltage now cycles much more smoothly at tickover;
* I never see less than 0.15V or more than 0.9V in normal driving;
* performance is measurably better across the range;
* fuel consumption is about 10% lower (did a 400 mile trip before, and
another one after).

Marco

[AR67202]

strange that your fuel consumption is lower, while your lambda readings at MOT were on the lean side...

that being said, when a lambda fails it'll be 99% chance to stray to the rich side...

[marco.marletta]

The MoT emissions test isn't done under load. There is a test at idle and a test at
around 2900 rpm without load. Because the engine is pulling so much better now,
I can use higher gears.

Marco