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Re: O2 sensor Primer
The obvious question: Why is there not a Bosch universal listed for my
i'm currently using a Ford 3 wire from an unknown donor car with unknown
history. car runs great in open loop(cold) but hesitates and lacks
performance when warmed. any suggestions?
all the best,
> > On Sun, 1 Dec 1996, Angela
Dupin wrote: >
> > What difference is there between the various 3 wire Bosch Audi sensors,
> > besides the connectors? is the signal different?
> Phil, & everyone else that is interested...
> This has been discussed in previous threads, but I guess there
> have been some problems with the archives, so for the benefit of those
> that weren't here, or can't get to the archives, I'll recap briefly.
> All oxygen sensors are alike basically. They compare the oxygen
> content of the exhaust gas to a reference gas housed in a small chamber
> inside the sensor. The difference between the two oxygen levels will
> cause a small voltage to develop between the two gases. The reference gas
> and the general construction is designed so that the voltage is 0.5v when
> the engine is burning at stoichiometry(approx 14.7:1.) A richer mixture is
> indicated by a greater voltage while a leaner mixture is indicated by a
> lower voltage. O2 sensors are extremely accurate at or near stoich, but
> they loose their accuracy as the mixture deviates from stoich by more than
> 10%. There are many factors that affect their accuracy, but that is a
> discussion that is far more advanced than I can lead.
> The variations in the commercially available sensors are mostly
> centrered around heaters, and ground locations. The single wire sensors
> have a signal output, and the sensor case is the ground. The 3 wire
> sensors have an internal heater which bringhs the sensor up to operating
> temperature mroe quickly, and will keep it at that temp if you idle the
> engine for too long. The 4-wire sensors add an additional wire for a
> separate ground, in case you are using an exhaust manifold material which
> does not conduct electricity.
> In case some of you are saying, "But there _are_ other types of
> sensors!" I would add that there is a new sensor called a wide band
> air/fuel ratio sensor which stays accurate from about 12:1 up to over
> 22:1 air/fuel ratios. These are very expensive, but nonetheless, a few
> manufacturers are using them, particularly in the newer "lean-burn" engines.
> That's the short form. HTH
> Later, ----------------------------------------------------------
> Graydon D. Stuckey '85 Mazda RX7 GS, no toys
> firstname.lastname@example.org '86 Audi 5000 CS Turbo Quattro, has toys
> Flint, Michigan USA '89 Thunderbird SC, lotsa toys