1 fast z Posted November 1, 2007 Share Posted November 1, 2007 I would suspect that one wire is the sensing, one is ground and one is ignition hot. But how do I know which ones, and what is a 4 wire for? Quote Link to comment Share on other sites More sharing options...
bubbleguinea Posted November 1, 2007 Share Posted November 1, 2007 a 4 wire is heated O2 sensor... most of the time a standard GM universal sensor...three wires most of the time are NOT universal....they have specific plugs for specific applications.... one goes to sensor one goes to power and two go to ground i believe most uni's are one black, one white, and two grey the black is the sensor, the white is the power, and greys are ground..... ***im not 100% sure, i forget this stuff easily.*** Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted November 1, 2007 Administrators Share Posted November 1, 2007 I would suspect that one wire is the sensing, one is ground and one is ignition hot. But how do I know which ones, and what is a 4 wire for? If you're looking for generic NB info... frequently 3-wire sensors will have two white wires and one black. The Black wire is the sensor output, and the two white wires are the heater. The heater has no polarity. Four wire sensors have an additional ground... sometimes its gray. HTH, Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted November 1, 2007 Administrators Share Posted November 1, 2007 most uni's are one black, one white, and two grey I've seen that color combo before but, just for clarification, Bosch's colors are different than the brand you're referencing. From Bosch's website... "All Bosch 4-wire sensors have a black wire for the signal, a gray wire for ground and 2 white wires for the heater" http://www.boschautoparts.com/Resources/FAQS/OxygenSensors.htm Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 5, 2007 Share Posted November 5, 2007 Yes, Volvo used 2 white tefzel wires (very nice!) on a Bosch-Injector style plug (hint for those sourcing their own 'Noid Light' pieces in the JY) as heater, with the signal separated in a shielded wire and it's own connector. Generally I will NOT wire the O2 Sensor to the Ignition Circuit. I will wire it off the Fuel Pump Circuit. This way, it only gets power when the car is running. I was shocked that the MSEFI forums had changed to following that advice some time ago. Makes sense to me... Quote Link to comment Share on other sites More sharing options...
bubbleguinea Posted November 5, 2007 Share Posted November 5, 2007 yeah ron you are right....however--- i would NOT recommend BOSCH o2 sensors....... unfortunalty napa still sells them, however most stores sell oxtra or standard sensors reboxed in some bosh boxes... for some reason, bosh o2's suck.... standard (fed. mog) and oxtra make GREAT sensors... Quote Link to comment Share on other sites More sharing options...
1 fast z Posted November 5, 2007 Author Share Posted November 5, 2007 What sort of applications would be good to get a 3 or 4 wire sensor from, preferably 3 wire? Quote Link to comment Share on other sites More sharing options...
olie05 Posted November 5, 2007 Share Posted November 5, 2007 I went with a four wire off a thunderbird, but if you're going new just go to autozone (or any other place you can get parts cheap) and get a universal 4 wire (or 3 wire if you must) from bosch (or ngk). Here's a link to the thread I posted about finding out which wires go where. http://forums.hybridz.org/showthread.php?t=124853&highlight=o2+sensor Quote Link to comment Share on other sites More sharing options...
bubbleguinea Posted November 7, 2007 Share Posted November 7, 2007 mid-90s chevy G series (van) they use a different kind of material inside the o2 that does the sensing...supposed to work better and last longer... to make it easy, a 1998 Chevy G1500 try to go to Orilley or PartsPlus Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 8, 2007 Share Posted November 8, 2007 Snagged mine from a Z31, same thread, I also harvested the connector. Runs into the Megasquirt. Quote Link to comment Share on other sites More sharing options...
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