BrickBoard Archives
The files contained in this listing have been automatically archived from the active forums. Because the vast majority of posts are now in one place, this archive is considered legacy. You should use the SEARCH feature OR choose your topic and select date tabs within the forum you choose.
More on Oxygen sensors[200/91] posted by Marten Douma on
Sunday, 7 February 1999, at 8:58 a.m.
Apologies for inflicting another question on you. Anybody know what the resistance of the O2 sensor heater should be? mine says 2.2 ohms. With only the green wire connected to the ECU I get a pretty stable .52 volts, which I have read in the archives to be the ECU reference voltage. Hopefully all is well at that end. If I connect the heater (there is ~13.5v on the harness side, btw) the sensor voltage decays over about 30 seconds to .01 volts. At no time does voltage sweep from .3 to .7 v.
A Bosch Ford 5 litre sensor is $97.80 (cdn) at a local import autoparts store, the Volvo sensor is $280 something. Can't remember for sure, my brain locked up at two-eight.......
Marten
Re: More on Oxygen sensors[200/91] posted by abe crombie on
Sunday, 7 February 1999, at 11:45 a.m.
That is the right resistance on the heater.
Before you replace sensor warm up engine attach voltmeter to O2 sensor lead and then momentarily pinch rubber return line behind fuel pressure regulator. If the voltage of sensor goes to .7-.9 V then look for something else making it lean. A faulty sensor can give you the low V reading but an air leak or defective MAF sensor can do the same.
Re: More on Oxygen sensors[200/91] posted by Topi on
Sunday, 7 February 1999, at 3:37 p.m.
I've been wondering: Can you replace the heated one with non-heated? Does the ECU know?
Re: More on Oxygen sensors[200/91] posted by abe crombie on
Monday, 8 February 1999, at 1:29 a.m.
Yes and no. The heated sensors are used to keep the signal active while idling. Idling in cold weather primarily, the sensor will fall below its 600F temp at which the reaction that makes it output voltage begins to work. If it were to stay above this temp the non-heated would be okay.
There are different sensors out there also. Most all the Bosch up to 92 have the same output voltage at the same O2 gradient. After 92 there are differences in some of the applications in this respect.
The Bendix/Siemens fuel sytem models use a different type sensor and it is not interchangeable with the Bosch units. This sensor does not work with a .5 V reference out of the ECM as does the Bosch versions. This type uses the heater power supply to feed a sensor circuit responds to O2 level variations. The Bosch type employs an electrochemical reaction and the heater is for stability of the temp (and therefore the signal) and not for the supply of current to be modified and used as output signal.