O2 Sensor Question
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
O2 Sensor Question
Hi All,
I have a 81 that has been converted to true duals with no cats installed, the ccc is still hooked up and functioning correctly. The car runs a little on the rich side and I'm wondering if I should be using the stock O2 sensors or should I be using something else? Any recommendations would be greatly appreciated....Tim
I have a 81 that has been converted to true duals with no cats installed, the ccc is still hooked up and functioning correctly. The car runs a little on the rich side and I'm wondering if I should be using the stock O2 sensors or should I be using something else? Any recommendations would be greatly appreciated....Tim
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
Hi All,
I have a 81 that has been converted to true duals with no cats installed, the ccc is still hooked up and functioning correctly. The car runs a little on the rich side and I'm wondering if I should be using the stock O2 sensors or should I be using something else? Any recommendations would be greatly appreciated....Tim
I have a 81 that has been converted to true duals with no cats installed, the ccc is still hooked up and functioning correctly. The car runs a little on the rich side and I'm wondering if I should be using the stock O2 sensors or should I be using something else? Any recommendations would be greatly appreciated....Tim
Rick B.
Melting Slicks
Joined: Mar 2007
Posts: 2,520
Likes: 11
From: Hinckley OH
I don't have any answers for you. I just have questions and food for thought that maybe someone else can shed some light on.
Was it converted from a Y pipe to duals? If so, I think every Y pipe I've seen has only had one O2 sensor in the common part of the pipe. With true duals, it seems like it would need two O2 sensors, but, is the CCC set up to handle two inputs? If not, would the CCC be able to handle having only one sensor on one of the duals? It just doesn't seem to me that that makes sense.
Was it converted from a Y pipe to duals? If so, I think every Y pipe I've seen has only had one O2 sensor in the common part of the pipe. With true duals, it seems like it would need two O2 sensors, but, is the CCC set up to handle two inputs? If not, would the CCC be able to handle having only one sensor on one of the duals? It just doesn't seem to me that that makes sense.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
The car still has the O2 sensors installed, one on each exhaust pipe in the original location as the car came stock. I believe the car came with two sensors but I'm not sure. I'm just wonder that with less back pressure are the sensors reading accurately. I've heard about people installing "wide band sensors" but I'm not sure what purpose that would serve. Thanks for your help Tim
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
All cars I know of from the early daze of EFI, through the early 90's had just one O2 sensor, typically in the pass bank/header/exhaust they figgered the driver's side was going along for the same measure....
but then in the early 90's they started putting dual then quad O2 sensors in, one before the cat and one after, on each side, or if just one cat...same thing only 2 of them....
but then in the early 90's they started putting dual then quad O2 sensors in, one before the cat and one after, on each side, or if just one cat...same thing only 2 of them....
Instructor
Joined: Sep 2009
Posts: 135
Likes: 2
From: Waterbury CT.
The O2 sensor only reads the oxygen in the exhaust system. With less back pressure you may have a drivability issue with the EGR system. Some EGR's run on back pressure and may not open if there is not enough back pressure. You should only have one O2 sensor on the car. If someone wired two O2 sensors together you could have problems. Also, make sure your air divert valve is working OK. If any unwanted air is going to the exhaust manifolds/headers your mixture will become rich. Is your check engine light on?
Le Mans Master
Joined: Jul 2000
Posts: 6,663
Likes: 162
From: columbia city in
when you have less back pressure because of flowthru mufflers or open cat ,your o2 sensor may not heat up enough.the fix for that is to go to a heated sensor .you will need to run one wire to a key on power source to the sensor .
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Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
Wow, Now you got me wondering. I bought this car the way it is set up now. I'll look again but I'm sure there is a sensor on both right and left pipes about a foot below the header connection. I am not getting any chk engine lights and the car runs fine. The air pump has been removed and I'm thinking the egr has been disconnected. Maybe I should just leave well enough alone. Tim
Tim
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
Larry, The EGR is connected but not through the ccc. Its connected to a therm-switch like older models. With that said I still do not know if its working correctly. After the engine is warmed up doesn't the egr remained closed. Thanks for all your help......Tim
Racer
Joined: Nov 2009
Posts: 289
Likes: 0
From: Franksville Wisconsin
The car still has the O2 sensors installed, one on each exhaust pipe in the original location as the car came stock. I believe the car came with two sensors but I'm not sure. I'm just wonder that with less back pressure are the sensors reading accurately. I've heard about people installing "wide band sensors" but I'm not sure what purpose that would serve. Thanks for your help Tim
It is important to have the computer system work. If you need one I have a sensor that has less then 200 miles on it when it was removed along with the computer etc..
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Only 1 came on the car on the drivers side. Sounds like it is in the correct place from your description. The EGR is Vac operated from a TVS on the intake manifold. If its running rich, yoyr operating O2 might have a problem, a new one will eliminate the problem. Get holf of a LM1 or something to get a real time measurement from the other side and see what its doing. You need to make sure the carb is correctly adjusted too.
Safety Car
Joined: Mar 2007
Posts: 3,652
Likes: 49
From: Bridgewater nj
From my experience the 81 only came with 1 02 sensor located in the Y-pipe after they merge. Although a heated sensor may be the fix? You also need to consider the learning mode
This sometime takes many hours of driving with the car running in all conditions. On my 82 I plan on using a dual in and dual out converter with an X-pipe in front where the O2 sensor will go. Good Luck
This sometime takes many hours of driving with the car running in all conditions. On my 82 I plan on using a dual in and dual out converter with an X-pipe in front where the O2 sensor will go. Good Luck
Instructor
Joined: Sep 2009
Posts: 135
Likes: 2
From: Waterbury CT.
There wasn't a learning mode in the early CCC systems. They only had three goals to meet before going into closed loop operation. They were engine temperature, (about 180 degrees), O2 sensor going above .450 volts and about three minutes of running time. Then it would go into closed loop. Hook a dwell meter to the M/C solenoid test point(Green connector next to carb) and set meter on 6 cylinder scale. When CCC system goes into closed loop mode the dwell meter should read between 6-54 degrees (varying)Ideal reading should be varying around 30 degrees. That's the simple test. A more complete test will require more meters and theory of operation knowledge.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 1,058
Likes: 27
From: Eastern North Carolina
"SSG26K" I have chk that M/C sol. adjustment and I have a reading pretty steady at 36 degrees. The needle does not vary much at all, however the reading will change if I turn the adjusting screw on top of the idle mixture sol. needle. Not sure if the steady reading is indicative of a problem or not. Thanks for your help....Tim
