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Originally Posted by wooo
Now I'm less sure of this  I just tested it again, after letting the car warm up, should this voltage range be in mV? When disconnecting the vacuum line (the same one as above), it holds steady at ~13 mV. Revving the engine for a second and letting off shows 300-400mV for a moment then back to fluctuating. I am not sure how much of this is a cheap chinese multimeter vs real measurements though, or if I'm measuring in the right range. I thought it should be .1-.9 V but got nothing but zeros in that range on my multimeter, so set it to 2000mV when testing, and it is jumping up and down fairly regularly. |
2,000 MV = 2 V
O2 sensors make 0.500 to 1.000 V when the exhaust is rich ( low O2 content ) , 0 to 0.500 V when the exhaust is lean ( high O2 content )
This type of O2 sensor does not have a linear output. The cross over point between rich / lean is very narrow. There is no way to tell if you are slightly rich or fully rich.
When the sensor fails, voltage drops , the computer thinks the motor is running lean then starts to add more fuel. Do you ever see more than 300 - 400 MV ?
Quote:
Originally Posted by wooo
Would this throw a code? How do I check this? I was going through coolant this summer more than I'd expect... maybe related?
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Not related. If a total open circuit it should trip a code, if off scale it might run rich but not trip a code. It depends on the code strategy.
Quote:
Originally Posted by wooo
Crossing my fingers that hasn't happened... can I see either of those visually? Is there a way to "unclog" it if that has happened?
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The pipes would have to be removed to take a look or a back pressure gauge used. You probably don't have this issue. Cats can sometimes clear out during a long hot run.