How many minutes Oxygen Sens. heater run ? How does the Coolant Temp Sens work ?

[sintox]

Hi all.

Newer Oxygen sensors have a heater.

I did a mod and currently using a 4-wire sensor. I turn on the heater manually. How many minutes does the heater run ? 1, 5, 10, 15, as long as engine run ?

My other question is:
The engine coolant temperature sensor might be "getting old and weak". How does it work: cold=small resistance ; hot=bigger resistance ? (Measured with engine hot/cold with connector off).

Thank you very much for your always useful info.

[chronoti]

10 min?? i think the ecu adjust it by the output reding.

[sintox]

Thank you Chronoti.
10 min. for the heater then.

As for ECT sensor, I will assume that I can test the terminal without even removing the sensor.

Now: 6kOhm - 200 Ohm
I am tempted to put a parallel 10kOhm to the wires if I dare to cut the wires somewhere.

I think the sensor is getting old (starting at very high resistance) but it's still functioning.

At my local shop it is $60CAD each ECT (I called 3 shops. Canadian NAPA is $80).

[Mike Gerber]

"As for ECT sensor, I will assume that I can test the terminal without even removing the sensor."

Yes, just remove the electrical connector and touch the 2 probes of your DVM to the 2 prongs on the sensor. Take a reading morning cold and then reinstall the electrical connector and then drive it for a while. Then remove the connector again and take your hot reading.

Mike

[sintox]

Thanks Mike. That I will do ASAP before spending money on a new sensor.
Simple but time-saving question: To disconnect the plug, (provided it has a tab), do I press "in" the tab or do I pry "out" the tab ?

It's a good time to use my Electrical Spray bottle to clean the plugs too.

If someone here wants to cross the border to pick up some parts (sensors, etc), let me know. I'm in Ottawa. ECT alone save you $30. Same thing for Oxygen sensors, etc.

[Larzzzz]

[quote=sintox;2921426......
I think the sensor is getting old (starting at very high resistance) but it's still functioning. [/quote]

That's the way it's supposed to work. Looking at the graph the horizontal line is temp, the verticle is resistance scaled in K (1000) ohms. Move the decimal point 3 places to the right to get ohms, ie, .2k ohms = 200 ohms.

Resistance is high when cold, low when hot

[sintox]

Sorry my bad: what I meant was it starts with higher resistance than specs.

That's my guess. I will check with a digital multi meter in the next few days (hot and cold engine).