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Old 01-20-2009, 04:24 AM   #9 (permalink)
cfg83
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1999 Saturn SW2 - '99 Saturn SW2 Wagon
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KJSatz -

Quote:
Originally Posted by KJSatz View Post
What impact does bump starting have on emissions?
One question I have (this was mentioned earlier, "PZEV" non-hybrids) is about a non-hybrid 2009 Camry I rented last weekend. It had the PZEV sticker on the window...how would that be, if the ICE never shuts off?
I think if you have a "one wire" 02 sensor that depends on the exhaust heat to get hot enough to work (like mine), it can cool off if you do a lot of bump starts. If the 02 sensor gets too cold, the ECU/PCM will go into open-loop mode, which is not as fuel efficient. If you have a "four wire or more" 02 sensor, then it is probably self-heating and will stay hot when the engine is off.

My car has two 02 sensors. The second one is post-cat and does have 4 wires. If I had my druthers, I would convert my 1-wire 02 sensor into a 4-wire, just like my other sensor. That would get me into closed-loop mode faster.

CarloSW2
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