I've seen it said that the o2 sensor comes into play only at light throttle. I notice that when my TPS hits its full voltage(around 4.65 v)and I'm in fifth gearl, I will be close to 70mph. Does anyone know at what voltage the ECU stops using the o2 sensor and goes into open loop? For clarification its 1 volt at idle and at the other end of the pot(TPS) its about 4.65 volts. Is it used by the ECU from 1-4.65v or cut off somewhere inbetween one volt and four point five volts? I'm talking 86-88 cars. Old fashion tps.

 

ddaahhhhhh!!!

brain...going...to.... explode...


AHHH!!!

 

IIRC it's either 3000 or 3800rpm when the computer goes open loop.

Just tap your voltmeter to the O2 wire and watch for when it stops dithering around .5v.

 

peejay....thank you. Right there in front of me. I now remember thinking about getting a second meter to watch the 02 and the tps voltage at the same time. Also remember thinking how cheap I am and didn't do it. Thanks for the info. I'm going to get a cheap digial meter to go with the one I have to satisfy my curiosity.