greenzee28

I have a 94 camaro with the 5.7 and it is automatic. The airpump was removed by the po otherwise it is stock.The car operates great when its cold but once its warm i get very bad hesitation during acceleration, what feels like a random miss at a constant speed, smells to be running rich, and i get quite a bit of smoke/soot out of the tail pipes. I also get a ses light that comes and goes. I previously had a problem with the opti and pulled the codes. I got a 13 and a 15. I tested the resistance on the cts and it seemed fine but replaced it anyway. I havent checked the codes again since my stalling issue but im wondering if there is anyway to test the o2 sensor and if there is anyway to know which side is causing the cel? Or if anyone thinks it could be something else causing it.

Injuneer

Always use Shoebox's LT1-specific code list:

http://shbox.com/1/Dtcs.htm


DTC 13 tells you the Bank 1 (driver side) O2 sensor isn't working. Shows an open circuit.

The O2 sensor is difficult to check. One way is to swap the left and right O2 sensors, and see if the problem follows the sensor (to DTC 63, Bank 2) = sensor problem; or stays on the left side (DTC 13) = faulty wiring.

You can also hook the sensor up to a high impedance volt meter, and heat the sensor with a propane torch to see is it becomes active at high temperature.


DTC 15 tells you there is problem with the CTS circuit, but not specifically the sensor. Could also be the wiring. Shoebox has a procedure that allows you to check the wiring:

4th Gen LT1 F-body Tech Articles


The ultimate diagnostic is to download the free Scan9495 software, get a cable and log the PCM under the conditions that produce the misfires and rich smell. We can help you interpret the data log:

https://www.camaroz28.com/forums/com...95-lt1-874306/

Misfires cause the PCM to pour extra fuel into the bank of the engine that has the misfire, compounding the misfire problem with three more cylinders running excessively rich.

[EDIT] Appears this is not a new problem.......

https://www.camaroz28.com/forums/fue...0/#post6974740

greenzee28

That is what i was looking for code 13 is specific to one side. Everwhere i was looking it didnt say bank 1 or 2. And your right the problem has been there since i got the car but the optispark did fix the stalling and not starting issue. I better save that link this time.

greenzee28

I replaced the bank 1 o2 sensor and now the car runs great the hesitation, miss and rich condition is gone. I did pull the codes again after replacing the o2 and both the 13 and 15 are gone but now i have a 63. What are the chances both o2 sensors were bad?

Injuneer

Did you possibly use leaded gasoline?

greenzee28

I have been running 87 unleaded but the car had the issue when i got it last december and i did use seafoam through a vacuum hose. Could this cause the other sensor to go bad?

Injuneer

You do realize that, unless you are up at a high altitude location, you are losing performance by using low octane fuel? This is clearly indicated in the Owner's Manual.

But low octane fuel will not damage the O2 sensors.