I rebuilt my q-jet and the car seems to be running fairly well. I am trying to adust the IAB by attaching the Dwell meter to the green wire near the firewall blower. Dwell seems to be at about 23 degrees. But, no matter what I do to the IAB the dwell does not change. But if I move the IAB enough I can tell the engine idle changes. Dwell does change if I press on the throttle. I thought maybe it was a bad O2, so I changed that. I am getting a 12 when I jumper the diag plug. MCS has 5/32 travel. How warm does the engine need to be?

any other ideas.

thanks
phil

 

The engine needs to be at full operating temperature so the O² sensor is hot enough to be active. Until then, the ECM is just going to remain in a "middle-of-the-road" mode on the MC solenoid.

 

Thanks Vader, Is that a function of the 02 sensor or does the ECM not read the 02 sensor until the temp sensor reaches 195 degrees?

 

The ECM doesn't pay much attention to the O2 until it becomes active, which is like 1200 degrees (exhaust temp, not coolant) and it knows the temp by the amount of activity.