Hi,

Yesterday I tried to see if the MCS on my CC Quadrajet was dead or not but it seems to work OK when I directly feed it 12V and seems to tick OK when the engine is running.

However, I've read in many places on this board that when you turn the key but don't start the engine the ECM is supposed to pulse the MCS for a few seconds. Mine doesn't do this at all.

What could be causing this, and is it anything to worry about?

 

My '83 (when it was carbed) would indeed pulse the MCS for several seconds after key on, and that's what I always understood to be normal. But, there were several things that were unique about the '82 model year, so I would suggest an additional test.

According to GM, the correct way to test the MCS is with a dwell meter, set on the 6 cylinder scale. There should be a light blue wire with a green connector near the passenger side firewall. With the engine running at operating temp, you should see a dwell reading of 30° (± 10°).

Good luck,

 

Thanks very much for getting back to me. I'll get my hands on a dwell meter and check it out.

 

correct. It should pulse for about 20-30 seconds when the key is rolled to "on" and the engine is *not* started up. Check continuity of wiring first.

 

If I jump the ALDL connector and turn the key to get codes from the computer, then it pulses the MCS without a problem in addition to giving me codes. The MCS operates when the car is running however.