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Ras12
08-04-2021, 08:36 PM
I have been having acceleration issues and finally got around to tracing the vacuum lines and found a lot of incorrect connections done by the previous owner. In particular I noticed that the Vacuum Solenoid Value located behind the fuel distribution block is not connected. I haven’t been able to find the wires and will keep looking. One lead on the solenoid is snapped off and it is rusted so I will order a new one. Was able to trace out the vacuum line from the distributor spark advance and the other line from the thermal vacuum control valve.

Question I have is can I connect the two vacuum lines together to bypass the value while I wait for the new one to come in?

Also, the PO tapped this (see attached circled in yellow) which I assume is another vacuum port. I am going to plug it and reroute the lines correctly. Anyone use this connection? If so what is it used for.

Thanks

Jason

Bitsyncmaster
08-05-2021, 06:25 AM
If you bypass the vacuum solenoid you will get advance at idle on a warmed up engine. This will probably cause a high RPM idle and hunting. You can run without advance but that would reduce the HP from your engine and probably reduce MPG.

Ron
08-05-2021, 09:22 AM
+1 ...bypassing the solenoid will also cause high timing during deceleration, which can cause preignition => damage.
Don't do it.

David T
08-05-2021, 04:11 PM
+1 ...bypassing the solenoid will also cause high timing during deceleration, which can cause preignition => damage.
Don't do it.

It also makes it hard to start especially when hot with all of that advance timing. Best advice is to try to get all of the OEM systems going correctly. By not hooking it up (correctly) you don't get all of the advance you need so you will not have all of the power and your gas mileage will be low.