TBI WBO2 Titania O2 VG30I

[patrowan]

I posted info tbi 86-89 AFM mods so I'll post something regarding the Titania O2 sensor used in those cars. In all my searches everything says the Titania O2 is a resistance device, which i'm sure to most ECM's it is. The O2 sensors 86-89 tbi nissans differ from the normal titania O2 in that it has 2 plugs one plug has 3 conductors (basically for the heater) 12V,gnd,gnd, the other plug is one conductor, signal. This signal is 1V when rich and close to 0V when lean.

I had made up a little circuit to convert the aux output from the Innovate WBO2 to resistance so I could change the closed loop mixture from the default 14.7 to something leaner. When I tried to hook it up I learned this so I just hooked the aux2 to the ECM and reset the voltage to 1V when rich and 0V when lean.

I had a scrap plug from an old harness so I unpluged the signal plug and pluged in the aux2, and everything worked as if it was stock. I then moved the switch point from 14.7 to 16.0 and now when in closed loop (which is just about all the time) I run between 15.4 and 16.2. I haven't tried leaner yet. I think i'll drive awhile this way and see if I notice any mpg difference. I have not notice any difference in driveablity. If i see a difference I'll try going leaner.

I haven't tried it (I don't have a resistance O2) but I belief you can take a 20K ohm resistor from the signal wire to gnd (rich condition) and then switch in a 1K ohm resistor across the 20K (2 in parallel) for the lean condition. Using the aux output of the WBO2. To do the switching you can use reed switch relay with 5V input. This isn't perfect, but the reed switch are rated at a billion cycles under no load and 5-6 million under rated load (350ma). The load across the contacts is only a couple milliamps, so life should be in the range of a couple 100 million cycles.

[krmiller07]

That's interesting. Just don't start bragging about your 3rd uncles cousin's aunt who is a wizard and worked as a consultant on all the Harry Potter movies, that tweaked your ECM so you get 1000 bhp at the rear wheels using a lawn mower dyno, and 200 mpg after shaving the door handles and removing the headlights for maximum aerodynamic efficiency in the wind tunnel built out of a utility shed made by Montgomery Wards that you picked up at rummage sale in Tibet...! LOL.

 

This is obviously a sarcastic joke related to someone posting on here about a month ago that specialized in talking out of his A** using braille'

 

KM