Ask for and share advice on using the PicoScope kit to fix vehicles here.
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We have an issue with a BMW M3 1996 3ltr. The co reading is off the meter (literally) but the odd thing is both O2 sensors work perfectly normal???!!! They oscillate at about 2hz when warm and range between .1 and .9 volts. Any ideas? We were thinking it could be that it is burning oil as the HC reading around 1100ppm. But appart from that I have never seen anything like this.
I don't know if it the intention of this forum but that will be told by some administrator. Obviously you need an answer quIckly and if you haven't solved the problem yet; you may want to look at a false lean situation, leak in exhaust system upstream or near lambda sensors 1.1 and/or 2.1.. ECU will be enriching because lambda sensor tells it the mixture is lean.
Any bodyI don't know if it the intention of this forum but that will be told by some administrator
What's the cross count ?They oscillate at about 2hz when warm and range between .1 and .9 volts
Misfiring ?We were thinking it could be that it is burning oil as the HC reading around 1100ppm
Are any fuel trim values available to you ?
Thanks for the replies so far. Much appreciated. This car did have a missfire (But if you've ever worked on one you'll know the fault codes and live data for this system are very basic indeed. It did not even recognize a missfire at all!) Thanks god for oscilloscopes we nailed it in 30 seconds and rectified that fault. We will bring it back in and look for an air leak in the exhaust system upstream of the o2 sensors. Cheers so far.