zapp168

iTrader: (7)

98 vette, the car is running like crap, if I leave the scan tool on, with the car not running B2S1 stays at 447 mv B1S1 drops down. I have replaced both the o2's and the computer and ohmed the harness.
When the car is running, B1S1 goes to 980 mv and the car runs rich, if I remove the O2 heater fuse all 4 readings go to mid 400's and the car smooths out. any ideas?
Thanks

Rhedalert

iTrader: (21)

sounds like the PCM is going into open loop and ignoring the sensor values, or the sensor gets too cold. This is all at idle I assume?

zapp168

iTrader: (7)

Yes at idle, if you drive the car it will run bad and sputter at low RPM as you accelerate it will clear up and go ok until RPMs drop again. I can understand the open loop part, but not even running the sensor voltage seems messed up?

zapp168

iTrader: (7)

The only code I get is P0132 B1S1 voltage high

Rhino79

iTrader: (7)

If an o2 code is thrown, you go into open loop mode full-time. Sounds like you need new o2's.

zapp168

iTrader: (7)

That was where I started, I replaced all four, same code same issue.

Rhedalert

iTrader: (21)

what does B1S1 drop down to when the engine is off?

zapp168

iTrader: (7)

Car is apart again now, but I think it dropped down to around 30mv. Also while running and while B1S1 is pinned B2S2 goes to zero. Fuel preasure is right around 58lb. and I swapped out the injectors with a known good set.

zapp168

iTrader: (7)

Computer is staying in open loop

Rhino79

iTrader: (7)

Sounds like a bad connector or wiring issue then. What about the tune, what temp is it supposed to enable Closed loop?? Just throwing out some possibilities.