Hey Fella's

Got a question...

I am considering purchasing that dual wideband 02 sensor set-up that FAST has...it has narrowband outout simulation built into it...which should allow a person to install the widebands in place of the there stock narrow bands and just use the analog sigs from the Fast unit to feed narrow band data into the PCM..which is fine if you have an OBDI car...I have a OBDI conversion in my 96 Impala SS, so the PCM in the car IS an OBDI PCM..but the 02 sensors and harness associated with them is the factory facilitated OBDII stuff, OBDI cars have a 3 wire set-up and OBDII have a 4..at least for 96..dont knw about any other year. The 3 wire set-up was just heater, ground and siggy...the 4 wire set-up was those same 3 things plus a bonus wire that I think is a low siggy output for some kind of comparison of the high and low siggies for 02 functionality for OBDII equipped cars..since OBDI didnt have that 4th wire..it shouldnt be looking for it right? and would it be possible for me to ground that Low siggy wire and leave the harness unplugged completly and just feed the sensor data to the PCM via the FAST unit's narrow band output...I dont think OBDI throws a code for the heater circuit..or does it? and I dont think it looks for that 4th wire low sig input, so that would mean the PCM would be happy long as it has: the heater circuit (+/-) happy (which it isnt looking for with OBDI right?) the 02 Sig (from the narrow band output of the fast) and low signal (which it isnt looking for right?) that accounts for all 4 wires..but dont know ifn this would work...anybody got some ideas?

 

B-Bodys must be quite a bit different than the F-Bodys. 93 F-Body (OBD-I) has single wire, unheated O2 sensors, 94-97 all have 4-wire, heated sensors, whether they are OBD-I or OBD-II. The "low reference" is essentially a signal ground. You should be able to connect the FAST output to the corresponding PCM pins. I think the Y-Bodys are all 4-wire sensors as well. Not sure why they would have done it so much differently on the B-Body.

Might want to try the "Computer Diagnostics & Programming" forum for more info.

 

Hey Fred...

Thanks a lot for the reply man..I appreciate it...maybe my 95 WAS a 4 wire 02 set-up...I thought it had 3 and the 96 (OBDII) that I have now has 4...hmm