Distributor and Module troubles

[red73mustang]

So I trying to get the timing smoothed out on my 73 W/302 V8 because it seams to idles fast and and will jump back and forth between gears occasionally, but the Distro shaft seams to be frozen in the intake and I can't twist it.  I sprayed it with WD40 and will let it sit, but was hoping for some other ideas.  

Also,the vacuum control module seams to be producing almost zero suction and I was thinking this could be the answer to my rough idle and up and down auto-shifting?

Do these modules ever go bad?

Thanks, Chet

 

[Don C]

Are you talking about the vacuum modulator on the transmission or the vacuum advance canister on the distributor. Neither one produces any vacuum, they rely on vacuum from the intake manifold or carburetor for them to work. If the vacuum modulator has a ruptured diaphragm it can suck transmission fluid into the intake and also cause a vacuum (air) leak that messes up the air/fuel ratio. If it doesn't function properly it will cause up and down shift problems.

A ruptured diaphragm in the vacuum advance will affect the ignition timing and also cause a vacuum leak.

Use a handheld vacuum pump to test both.

 

[sciabola13]

Sorry to hijack thread. But you mean using a hand vacuum pump a la brake bleed kits to apply vacuum to those components and then see if they leak vacuum?

Sent from my iPhone using Tapatalk

 

[Don C]

Yes, see if you can get any vacuum reading while pumping it and then if it will hold vacuum. You need one that is a combination brake bleeder/vacuum tester that has a gauge.

 

[red73mustang]

Thanks for all the great info Don. I was originally talking about the vacuum advance canister on the Distro, but now I may need to look at or replace the module on the trans.

As for getting the dizzy to move I was considering rapping it with a brass punch?

 

[Don C]

This thread may help:

https://www.7173mustangs.com/thread-frozen-distributor?highlight=Frozen+distributor