Driving the car more since fixing the head gasket. Runs strong! BUT, I realized there has been something wrong with the vacuum advance for years. I reset the idle and re-tuned the carb after the head job.
Now, the car idles properly when cold, but after the engine warms up, idles at 1000-1200 rpm. When I pull the vacuum advance, the idle drops back down to 700rpm. I had apparently compensated for this by setting the idle to 700rpm while hot, which when cold would make the car barely idle at 500rpm.
I have everything hooked up as per the underhood diagram: the vacuum line to the advance can goes to the triple connector on the vacuum tree on the intake that has the electrical plug on it. (Side note: about 15 years ago, I went through the vacuum system and the diagram to verify everything. The vacuum advance at that time was plugged onto the other vacuum tree on the intake without the electrical plug (the green or purple one). At the time, I switched them because the diagram clearly shows it going to a tree with an electrical plug.)
So how are these vacuum lines supposed to be hooked up? How much vacuum at the advance should I be measuring at idle and how much advance should it contribute?
Thank you!
Edit: just had a thought...could I be getting too much vacuum to the advance because the primary throttle is adjusted open too far? Maybe I need to open the secondaries more to get the idle up?
Connect With Us