Bad O2 sensor - knock at idle ??
Thread Starter
Instructor
Joined: Aug 2001
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From: brighton mi
Bad O2 sensor - knock at idle ??
Hello fellow Corvette enthusiast,
I have a 94 Vert, Auto with 64k miles and at idle I am getting a knocking noise. When I take the engine up to 1,500rpm and beyond the knocking goes away. After driving the car for about 15 minutes, the Service Engine Light comes on. I took the car to AutoZone to have it scanned; the code came in as an O2 sensor.
My question is can a bad O2 sensor be the cause of this knock due to improper fuel mixture?
I have a 94 Vert, Auto with 64k miles and at idle I am getting a knocking noise. When I take the engine up to 1,500rpm and beyond the knocking goes away. After driving the car for about 15 minutes, the Service Engine Light comes on. I took the car to AutoZone to have it scanned; the code came in as an O2 sensor.
My question is can a bad O2 sensor be the cause of this knock due to improper fuel mixture?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
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From: seattle WA
My answer to that would be yes. If you're referring to pinging, also refered to as knock, actually pre-detonation. Have you seen a drop in MPG and performance issue?
Last edited by rick lambert; Nov 18, 2008 at 12:48 PM.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
get a mechanics stethascope, like the doctors, cheap, isolate where the noise is comming from. I said yes on the 02 being able to cause pinging, but usually when the 02 goes bad mileage goes down.
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Isn't the function of the O2 sensor to tell the ECM that it can go into closed loop when the sensor detects a certain level of gasses? If the ECM doesn't go into closed loop when it should, fuel mileage will drop.
A bad grade of gas or even the wintertime gasoline blends can cause pinging but it would be under some level of engine load like part-throttle or full throttle acceleration or even just going uphill.
A code that points to an O2 sensor means that the sensor is either not working or the signal value being sent is out of range. The sensor is not terribly expensive so replacing it would be a step to take followed by clearing the code.
A bad grade of gas or even the wintertime gasoline blends can cause pinging but it would be under some level of engine load like part-throttle or full throttle acceleration or even just going uphill.
A code that points to an O2 sensor means that the sensor is either not working or the signal value being sent is out of range. The sensor is not terribly expensive so replacing it would be a step to take followed by clearing the code.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I'm not sure about the 94, I know earlier C4s only had one, but I do believe the laters have two, and I'm not sure if AutoZone scanned it or just pulled the code. Normally on later C4s, when an 02 sensor code is thrown it will also tell which bank, meaning left or right side 02. Do you know if they scanned it or just pulled codes? there is a difference! But if it were mine and it had two, I'd replace both anyway.
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Verdad Gallardo
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From: Hamilton New Jersey
Isn't the function of the O2 sensor to tell the ECM that it can go into closed loop when the sensor detects a certain level of gasses? If the ECM doesn't go into closed loop when it should, fuel mileage will drop.
A bad grade of gas or even the wintertime gasoline blends can cause pinging but it would be under some level of engine load like part-throttle or full throttle acceleration or even just going uphill.
A code that points to an O2 sensor means that the sensor is either not working or the signal value being sent is out of range. The sensor is not terribly expensive so replacing it would be a step to take followed by clearing the code.
A bad grade of gas or even the wintertime gasoline blends can cause pinging but it would be under some level of engine load like part-throttle or full throttle acceleration or even just going uphill.
A code that points to an O2 sensor means that the sensor is either not working or the signal value being sent is out of range. The sensor is not terribly expensive so replacing it would be a step to take followed by clearing the code.
Le Mans Master
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From: Australia
Thread Starter
Instructor
Joined: Aug 2001
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From: brighton mi
I will also replace both O2 sensors. That seems like the right thing to do. I did a search on O2 sensor replacement and got about 1 million results. Does anyone know the best thread for this?
