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"Check Engine" light blues

New Codes...again

This is what I got after disconecting the Battery for 1/2 hr and then running the car for several days...the light just came on again at extended Idle...and goes off when I start moving.

*/*** 3 times

**** 6 times

Then it keeps repeating the above 2 sequences.
Any way to nail it down?
Thanks for all your tips...Ray.
 
Hi Ray,
The fault codes you're getting are 13 & 44, but it should flash code 12 as well :confused
Code 13 is "Oxygen Sensor Circuit"
Code 44 is "Oxygen Sensor Lean"
so it looks like you're narrowing it down :) The code that was there before, but not now (23), is "Mixture Control Solenoid Circuit", so either disconnecting/reconnecting the computer plugs has cleared it (could have been a bad connection?) or it's just gone! Have you touched the connector on the carb for the M/C solenoid?
Back to the O2 sensor: How old is the sensor? It could just simply be that the sensor needs replacing. Is the sensor in the stock location just down from the manifold? If the sensor is fairly new then I'd very carefully check all connections from the sensor back to the ECM. Pay particular attention to the connector at the sensor itself as it can get covered in a lot of oil/crud. The voltages in this circuit are low (up to 1V?), so something as simple as a dirty/oily connection can wreak havoc.
I can't remember if low voltage from the sensor is a lean or a rich condition. Hopefully somebody will jump in & say (Hib?), but if low voltage = lean then bad connections could easily be the problem.

This is a long shot & a complete guess, & I could get shot down in flames for it! :D I've fitted Headers on mine which meant moving the O2 sensor downstream. Doing research on Headers & O2 sensors I found out that if the sensor is further downstream from the exhaust ports than it was designed to be, then it can very easily cool to below its operating temperature at idle, giving bad readings. People have had this problem & clear it by raising the revs for a while to heat it back up. Could your sensor be doing the same due to carbon build up insulating it? Just a wild guess :)
I'll go through my manual & see if it gives any easy methods of finding the fault.
Good luck
Paul
 
UkPaul, you are correct. Low voltage (below 450 millivolts) indicates a lean condition. There are a few conditions that can create this code. First and most obvious, is the car can be running lean for whatever reason (vacuum leak, etc.). The other reasons are: sensor is bad or dead-meaning not being able to generate any voltage-when the computer sees this for an extended period-it trips the code. The other possibility is the sensor is fouled with carbon. Finally, the last option is a bad connection or a bad computer.
Try disconnecting the o2 sensor and measure the voltage at the terminals with the key on and the engine off. You should see about 350 to 450 millivolts on the engine harness-not the o2 sensor. If that's OK, then take the sensor out and look at the tip. If it's carboned up, the carbon will actually block the sensor and prevent it from working. GM recommends replacing them at 30,000 miles.
 
Thanks guys...I've owned the car since new in 81...it's NEVER had an O2 sensor or anything computer related replaced.
I did replace the EGR valve several years ago when I rebult the Heads and installed a new Cam+Lifters....but thats about it.

Just where is the O2 sensor on my 81? I'll test it with a meter and most likely install a new one....hey it's 23 years old with 114,00 miles on it.
Thanks again for the feed back...Ray

PS. great Forum here for sure.
 
It's on the drivers side exhaust pipe, just down from the manifold. Hope changing it solves the problems.
:beer
 
Update...finally got the new Bosh 02 sensor in.
Soooo far NO check engine light.
BUT...I tell ya the car (seems )to be running better than ever.
Idle has smoothed out and just appears to be better all around!
Thanks againg for all the time/suggestions given...Ray
 
HammerDown said:
Update...finally got the new Bosh 02 sensor in.
Soooo far NO check engine light.
BUT...I tell ya the car (seems )to be running better than ever.
Idle has smoothed out and just appears to be better all around!
Thanks againg for all the time/suggestions given...Ray

HI I WAS READING YOUR POST ABOUT THE CHECK ENGINE LIGHT , MINE DOES THE SAME EXCACT THING, HOW MUCH $$$ WAS THE O2 SENOR AND WHERE DOES IT GO , WAS IT HARD TO PUT IN?

Thanks, Rick
 

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