blue wire for o2 readout?
 

i heard that it will only tell you the voltage read out, but what voltage is ideal?
and will it display it with your other readings?

From memory: It's output is from 0-1vdc.

Cruising at a steady speed, say 60mph and not stabbing at the pedal, it will read rapidly, on either side of 0.5 vdc. It'll be jumping back and forth on either side of that figure.

IF your in say third gear, and stomping the pedal going for seven grand before shifting, then the voltage will be steadier and be in the 0.7 - 0.9 vdc range. It'll jump around maybe a tad but on the whole be b/t those figures as long as the pedal is to the floor.

Now say you are doing the above and then let off the pedal completly. The volage will drop to 0 vdc or darn close to that and stay there until you apply pressure to the pedal again OR until the rpms drop down below about 1100 rpm (guessing here again at the figure).

I think it only will be displayed on the SENSOR CK page. I really don't know for sure, but I'm fairly sure that's how the cow chews the cabbage. I have not looked at a meter's voltage while connected to the 02 sensor in a couple of years or more.

Ah someone got the idea as me.

Yes you can only view it in Sensor Chk. I don't know for sure how the SAFC will react to it. I think it wont even know its there because I believe you need to set the AFL IN and OUT correctly for it to use both INPUTs instead of just one for the AFL. So we may be safe and have it only read the volt output instead of it actually trying to adjust fuel from what it is seeing. I get some feedback on that wire for IN2 so I don't really think it does anything untill you set the IN OUT correctly.

I got the idea of the blue wire off this forum. I forget just where I read it. It's been a year or two ago. Might be on this very forum down at the bottom, maybe.

Like this thread: https://www.rx7club.com/forum/showth...ight=blue+wire

Just did an Advanced search and put in the words BLUE WIRE and had ten or fifteen hits.

I forgot to mention one other thing. IF you have the ACV and airpump still on your engine, then the reading of the 02 will be close to zero when at idle ...because the ACV mixes air from the airpump to the exaust ports which are located prior to the 02 sensor itself. IF you see this, then pull the BLUE plug off the Relief solenoid and the reading will go to the 0.6 vdc range because the air will now not be going to the exaust ports.

I went out the other day and connected the Blue wire and compared that reading with the reading off a RTEK and they are the same for all practical purposes. So,. yes, the blue wire works but only when in Sensor Check.

I like your idea of feeding the AFR to the blue PRS input.
The next step would be connecting a low end wideband to that wire.
That would allow the S-AFC to do some basic logging.

I used the boost signal to the gray wire instead of the TPS, so it would transition to the high map with boost.
Then I used the blue wire to monitor the TPS. It displayed as PRS, but you could verify that your TPS sweep was good.
(Kinda backwards, but it worked great.)

-Bill