hi a newbie so please be gentle!
i recently bought a mk4 astra 1400 16v on a w plate, seemed a bit heavy on fuel and the engine management light came on intermittently, mainly under light cruising conditions.
got the codes read, dont know the exact error code but was told get an oxy sensor. got a brand new direct fit oxy sensor from e-bay, fitted it in my lunch break yesterday and left the battery disconnected until about half five. the old oxy sensor 'cap' had fallen off and is now rattling round in the cat, the sensor tip was heavily burnt away.
anyway, did an emissions test, CO and HC readings off the scale, after alot of fast idling to clear the cat etc got it down to 1.5% CO at fast idle and about 5% at idle.
checked codes with snap-on solus, gave P0170 Mixture too lean error.
Im a bit confused as to why the error is saying mixture too lean but the emissions are too high, is this the ecu trying to compensate for the low readings and over-fuelling?
so anyway, was thinking of taking out airflow meter and cleaning, and ive just noticed I have an EGR valve, if this is sticking would this cause the faulty mixture reading? also there is a very slight blow at the manifold to downpipe gasket, cant hear it but can see the carbon, its close to where the oxy sensor sits, would this affect the oxy sensor readings?
oh, one thing ive noticed too is that with the old sensor the manamgement light flickered on and off, with the new sensor it takes a while to come on but then stays on......