Hello Everyone,

I am trying to figure out wether or not my vacuum advance is working properly. I've attached my vacuum gun to both ports while the engine is running and I the retard seems to work, but not the advance. I took the vacuum module off of the distributor and then used the vacuum gun on each port; this time the retard moves and holds, but the advance doesn't. Does this mean it's bad, or they work together and i need both be hooked up?

Thanks for any advice.

Disconnect both lines. Connect your timing light. Start the car and while watching the timing marks, rev the engine. Does the timing advance? If it does then your advance mechanism is working. That is a starting point.

The timing set up on the car is an overly complicated disaster. It uses solenoids to activate the timing vacuums at all kinds of weird times. Below about 80C the car has a sensor which shuts off the retard vacuum. and a few other quirks which were incorporated into the ignition system to meet U.S. emissions specifications.

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Hello, I will try that. Yes, the timing procedure seem very complicated. I'll keep wrenching.

Thanks.