Really quick here is my problem, O2's are stuck in the 450 mv range, and barely move, jumping 10 mv or less whether the car is idling or revving. I traced the signal wires back to the computer, and I have continuity with both. Also, the right bank has started slowly dropping in mv, from 450 mv all the way down to 4 mv, while the car is running.

Ok so I tried new autozone O2 sensors and still had a problem. Converted to 94+ heated sensors and wiring (all purchased from GM dealer), and still running rich. O2 sensors are still giving me the same reading. I thought maybe this is normal for 383 engines, stupid idea though. Help me out guys. Someone told me that is possibly the computer. What do u guys think. Help please. I have had the engine in the car for more then an year now and still havn't enjoyed it because of this.

 

02 sensor problem..not 383 related..does the car run terrible or something? Maybe the data could be wrong...what are u using to scan?

Cody

 

Still on stock programming??

 

Not on stock programming. The car actually runs pretty good. But you can smell the gas a block away and if you are in the car your eyes hurt because of all the gas. I believe my buddy is using autotap. But I even took the car to a shop and had it dyno tuned and they told me the same thing, its the O2 sensors. So the only thing that they recommended was to replace the computer since i have tried three different sets of O2 sensors.

 

I guess I have no other choice but to replace the computer. Don't know what else to do.

 

it could be a faulty injector. If you car is OBD1, it will not read each cylinder. If one injector is giving too much gas while the rest are ok, the computer will adjust for the average and one of your cylinders will run too rich and the rest slightly lean, despite normal readings from your 02.

this is pure theory, i have never came across anything like this.

 

Did you wire the heated O2 sensors properly? Unscrew one out of the exhaust, plug it in to the wiring harness, and turn the ignition key to "on" (don't start the car, though) and let it sit for a minute - I think it should start glowing red if the wiring is done right.

Long tubes can make it difficult for the O2 sensors to get up to temp. On my 93, I had the same problems you're having after installing hooker LTs. Swapped in the heated O2's, and that fixed the problem.

 

You could unplug the O2's and let it run in open loop all the time. It will just use the A/F table in the PCM to "guess" at the correct ratio. This table is most likely still on stock values so it may still run rich. Are your O2's getting in the 800+ range. If not, then it sounds like you have false lean condition. Exhaust leaks can casue this. Fresh air is being sucked into the exhaust and read by the O2. The pcm will keep adding fuel and the O2's will always read lean (low volt reading) The side with the leak will run pig rich. Check the plugs.

Also, you can put the stock injectors back in. If the computer is set up for your 30lb ones it will lean out the car. I would do it to see if the gas smell went away.