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Hi. I recently purchased an 81 vette, with 47k miles, and it started having an intermittent O2 lean fault code. When I purchased the car, it had previously been sitting in storage for several months, not being driven. There wasn't much fuel in the tank, so I added 5 gallons of 87 octane. Started engine and it began sputtering and making popping sounds. It didn't do this while I was with the seller on a test drive. The problem seems to have happened after adding the new fuel. Engine stopped doing this after about 10 minutes. However, this is when the fault code first occurred. Is it possible it's just bad fuel causing this or should I have ran a higher octane? The previous owner used 91. Not sure if it's the fuel or a faulty O2 sensor. The sensor is cheaper than buying a dwell meter and going through the troubleshooting procedure in the GM shop manual.
It is a computer controlled carb. The sensors are probably right. The carb probably needs gone through. Then many feel any code on that computer is remedied by throwing the computer in the river and getting a non-ecu carb.
if no smog in your state,
a new carb and dist/ expensive/ way to lock up tranny
will make the car a 80 or earlier type car.
the computer, smog devices, CARB, take some learning.
try some heavy duty carb cleaner.
can't help because i ain't there.
thanks for the info. Yeah I put some seafoam in the tank. Thought of checking the timing too. Would a basic timing light work? I havent had a carborated car in 30 years so I'm relearning this stuff.
From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Originally Posted by dalehuff
Hi. I recently purchased an 81 vette, with 47k miles, and it started having an intermittent O2 lean fault code. When I purchased the car, it had previously been sitting in storage for several months, not being driven. There wasn't much fuel in the tank, so I added 5 gallons of 87 octane. Started engine and it began sputtering and making popping sounds. It didn't do this while I was with the seller on a test drive. The problem seems to have happened after adding the new fuel. Engine stopped doing this after about 10 minutes. However, this is when the fault code first occurred. Is it possible it's just bad fuel causing this or should I have ran a higher octane? The previous owner used 91. Not sure if it's the fuel or a faulty O2 sensor. The sensor is cheaper than buying a dwell meter and going through the troubleshooting procedure in the GM shop manual.
Not sure if the 81 has the same codes as the 82, but they are similar. 44 would be an O2 issue. I'm sure that the manual has you go through the troubleshooting procedure for that code and it's probably the O2 sensor, but could be something in the harness or ECM. The 81 is a 1st gen ECM and still a carb, 82 being 2nd gen ECM and TBI. It could like mentioned the carb is acting up. Good luck with the issue. Post up your findings for others.
Last edited by Buccaneer; Mar 28, 2018 at 10:59 PM.
doubtful it is timing and you have to disconnect the ECU from the distributor to check it. Why did put only 5 gallons in a car with almost no gas in it?
Did you buy the gas at a station you normally go to?
I didn't have insurance or registration on it yet. So, I couldnt drive to the gas station. I just used a 5 gallon gas can to fill it up. I ended up putting another 5 gallons in with seafoam.
Hi. I recently purchased an 81 vette, with 47k miles, and it started having an intermittent O2 lean fault code. When I purchased the car, it had previously been sitting in storage for several months, not being driven. There wasn't much fuel in the tank, so I added 5 gallons of 87 octane. Started engine and it began sputtering and making popping sounds. It didn't do this while I was with the seller on a test drive. The problem seems to have happened after adding the new fuel. Engine stopped doing this after about 10 minutes. However, this is when the fault code first occurred. Is it possible it's just bad fuel causing this or should I have ran a higher octane? The previous owner used 91. Not sure if it's the fuel or a faulty O2 sensor. The sensor is cheaper than buying a dwell meter and going through the troubleshooting procedure in the GM shop manual.
Take apart your connectors at the cpu .clean them and reconnect.Disconnect battery for at least a minutereconnect and go for a good long drive.Sometimes the contacts get a little oxidized.
Sometimes the ecu, O2 sensor and the rest of the sensors are reading correctly and the 37 year old carb is gummed up and not feeding the correct amount of fuel, causing a lean reading. Replacing the oxy sensor is the equivalent of killing the messenger.
Last edited by derekderek; Mar 30, 2018 at 06:37 AM.
If you read my first comment, I just purchased the car and it started giving me a code 44 after putting new gas in. The previous owner had been using it as a daily driver. All I wanted to know is what can cause a lean O2 reading and that's it. I would have expected you to read all the comments and not be an idiot.