engine light on 81 vette
Thread Starter
2nd Gear
Joined: Nov 2011
Posts: 2
Likes: 0
engine light on 81 vette
i have a problem on my 81 vette i just install side pipes and hooker header on it and now my engine light went on and it stay on i dont know what to do can any 1 out there help me? thanks alots
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
The '81 car had the first version of electronic controls for the engine. It had a unique (one year only design) carburetor, distributor, and ECM (electronic control module...computer). It also had an oxygen sensor in the exhaust downpipe which sent emission data to the ECM for regulating fuel mixture and distributor timing.
If your "Check Engine" light is on, there is a trouble code that has been logged into the ECM. You need to download that code and address the respective hardware problem indicated by the code(s).
If your "Check Engine" light is on, there is a trouble code that has been logged into the ECM. You need to download that code and address the respective hardware problem indicated by the code(s).
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
7T1 and A1 are correct.
You may not have installed the O2 sensor back in the drivers side header.
No reason at all you can't make significant HP gains With the CCC in place and functioning
You may not have installed the O2 sensor back in the drivers side header.
No reason at all you can't make significant HP gains With the CCC in place and functioning
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Instructor
Joined: Aug 2010
Posts: 233
Likes: 18
From: Monrovia Md
The computer will tell you why -- read the codes. To do this, pull the ash tray, there is a connector directly under it. With engine off, short the two pins closest to the driver side. turn on the key (not the engine) the check engine light will begin to blink (you will also hear an audible clicking in the engine compartment, it is the carb mixture solenoid switch and is normal). One blink, pause, two blinks (code12) and repeat that three times. After the code 12 (normal, happens every time) there will be one or more codes blinked at you (example: Blink, Blink pause, blink, blink, blink is code 23). It will blink each code three times. When all codes are complete there will be another set of three 12's. When you see the 12 again you are done.
Let us know what the codes are and we can help you from there. Also, think about getting an 81 service manual, fantastic section on the CCC
My first thought -- did you connect the oxygen sensor back up, should be on the downtubes of the drivers side header
Let us know what the codes are and we can help you from there. Also, think about getting an 81 service manual, fantastic section on the CCC
My first thought -- did you connect the oxygen sensor back up, should be on the downtubes of the drivers side header
Last edited by wajulia; Nov 4, 2011 at 01:21 PM.
Drifting
Joined: Jun 2011
Posts: 1,704
Likes: 27
Since he just installed headers and sidepipes it pretty obvious it is a missing 02 sensor, in which case you have 2 options:
1) weld a bung into your sidepipe or header and re-install the sensor, or
2) Remove the ECM, which means you'll also have to replace the carb and distributor.
1) weld a bung into your sidepipe or header and re-install the sensor, or
2) Remove the ECM, which means you'll also have to replace the carb and distributor.
