1992 LT1 with 63, and 64 O2 codes

[Ben Edwards]

I have a 1992 coupe with an LT1 motor, all stock with about 62,000 miles on it. The problem I am having is after the engine gets warm the "Service Engine Soon" light will come on for about 2 minutes then turn off. I checked the codes and got a 63 and 64, which was lean right side heated 02 sensor, and lean right bank 02 sensor. There is also a slight lag in acceleration at low rpm's. I have replaced the TPS and the fuel filter and then cleared the codes. After clearing the codes she runs great for awhile then the problem starts again. I'm sure I will need to replace one of the right side O2 sensors, I am just trying to determine which one, or both, or if it is an entirely different issue all together. Any input on this would be greatly appreciated, thank you.

Ben

 

[Hib Halverson]

It is possible but unlikely that simply replacing the oxygen sensors will solve the problem. DTC 63 and DTC64 set when the system is lean. That you have it on both sides and that you've already felt some abnormal drivability characteristics indicates a probable fuel system fault.

The only way to proceed with those problems is to obtain the factory service manual and follow the diagnostic and solution information for those two codes. That could lead you to replace the sensors but, also likely, it will lead you to a problem which is causing the system to run lean.

You can get a Service Manual from CAC sponsor Zip Products.

 

[Jeb]

It is possible but unlikely that simply replacing the oxygen sensors will solve the problem. DTC 63 and DTC64 set when the system is lean. That you have it on both sides and that you've already felt some abnormal drivability characteristics indicates a probable fuel system fault.

The only way to proceed with those problems is to obtain the factory service manual and follow the diagnostic and solution information for those two codes. That could lead you to replace the sensors but, also likely, it will lead you to a problem which is causing the system to run lean.

You can get a Service Manual from CAC sponsor Zip Products.

I thought the problem was limited to the right side, not both sides.

That's not to say using the SM is a bad idea but it's not certain that the problem is generic to the entire fuel system. Something is happening on the right side only to cause the lean condition.

 

[Ben Edwards]

Reply

The problem is only with the right side O2 sensors, the one on the left is not showing any codes, thanks again for all the information and I will look into getting a SM. I'm thinking it is the sensors or something electronic because after clearing the codes it runs great with no hesitation or issues, then once it warms up the light comes on for a bit then goes out and the hesitation at low rpms returns.hnoes

 

[John Robinson]

Codes

Code 63 is for the right bank O2 sensor having an open circuit. Per FSM check the wire for the sensor and make sure it is not touching the exhaust and shorting out. Code 64 is a lean exhaust indicated. You need to look for what is causing that side to run lean like an injector that is plugged or going bad. Codes do not always mean that (In your case the O2 sensor is bad)they simply tell you that the ecm is getting information that there is a problem in that system.

Don't forget to look at the fuel pump and pressure. AS for the runs good until it warms up sounds like the ecm is frustrated and going back and forth between open and closed loop.

 

[Ben Edwards]

Helpful info!

Thanks for the input everyone, I'm going to replace the O2 sensors and clean and test the injectors tonight. Then clear the codes and see what happens.:eyerole Thanks again for all the help and I will post the results when I am finished.

 

[Ben Edwards]

Problem solved!

I replaced the O2 sensors on both sides, cleared the codes and all issues have dissappeared! She is running great and the gas mileage has improved quite a bit, thanks to all that helped out with your useful information!