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1994-2002 [Subscribe to Daily Digest] |
I have been following your resistance check suggestions, and to be honest, I haven't found a single source or evidence that confirms that the exhaustsystem is used to deliver ground for O2 sensor.
A matter a fact is that if the exhaust system was used as a ground lead, they would have put a ground strap on there, and not relied on the flange connection at turbo or exhaust manifold, since that's the only spot where exhaust system is connected to the rest of car by metal on many models.
I know you had good luck at one point by cleaning the O2 sensor, but I beleive that was a coincident.
The three wire sensor have one power lead and one ground lead for the heating element, the third black wire doesn't need a ground. It creates power all by itself when the hot exhaustgasses flows by and heat up the different metals inside sensor. The ECU is sending 0.5V reference signal toward the O2 sensor when cold, but that signal is overpowered by the fluctuating signal from O2 sensor when hot.
The 4 wire sensor also have a power and ground lead for heating element and two signal wires that works unison but at two different voltage levels to send information to ECU.
That's where people installing an aftermarket O2 sensor goes wrong, the aftermarket calls one of the wires for ground and the other for signal, and if you install those two wires on the wrong signalwires coming from car, it doesn't work. Heck, I don't know if it works even when chosing the right wires.
But I think I read about one guy succeding with installing a Walker 4 wire.
I don't have time right now to figure out an aftermarket solution for O2 wires, the reason for that is, I have found out more and more about how sensitive the OBD2 sytem is from 96 and up when it comes to disturbance from faulty sensor.
And many of the problems takes sometimes weeks and in some cases month before it triggers the faultcode and CE light again. If I use substandard components in those cars, I'm really in for a asswhooping trying to find the created fault.
posted by 66.134.55...
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