The Stovebolt Site Forums The Shop Area Engine Shop Stumped by Vacuum

Hey guys, So during my recent rewire I replaced my distributor with an HEI (stock cardone). Now when I plug the vacuum line up to the HEI's secondary it dies. I have a 250 motor from a 74 nova. Any ideas what my problem could be. need to have this thing out running during this beautiful weather.

Thanks in advance

jtroberts The cable on the pickup coil is probably worn out. It means ppull the distributor take the shaft out,install a new pickup coil. If distributor is old it may have sludge on the shaft that will make it hard to get apart. use penetrating oil and patience,then emery cloth! When I make a conversion homemade one it will be that same way !

It's a brand new stock cardone HEI distributor

jtroberts Sounds more like a ground problem then,getting into something when vacuum moves the mechanism, look for a clash in there.

Do you mean when you connect the vacuum line to the vacuum advance canister (looks like a metal biscuit, sort of)? If so, then take a length of rubber vacuum tubing, connect one end to the advance canister pipe and suck on the other end. You should be able to know if the advance is working. It won't take a lot of vacuum, either. If on the other hand you get no resistance when you suck on that tube, then it tells you the vacuum diaphragm is ruptured (common...happens when they're assembled and you see it pretty often today because they're made in a country with 5 letters beginning with C which isn't Chile or Czech). If you get no resistance, then you know your carburetor is getting open air back to it, and if your distributor was meant to work on manifold vacuum (as opposed to ported vacuum), then yes...with an open vacuum line your engine will die.

As I recall there were a couple of different versions of the 250 and one had ported vacuum while the other had manifold vacuum. If you have manifold vacuum and it is around 17 or so, then hooking that up to the distributor might cause it to go fully advanced immediately. If you have ported vacuum, there probably will be little to no vacuum at idle.

Let's start there. Can you tell us if your vacuum advance line connects to the base of the carburetor above or below where the throttle valve will be?

Yes, the vacuum advance canister. I haven't had a chance yet to try your suggestion Jon, but hopefully I can this evening. I do believe without looking that the advance line connect to the base of the carb.

I'm inclined to believe it has something to do with the dist. Like Fixite says when the advance goes in it moves the pickup coil. It is opening the continuity or shorting it.
I believe Cardone is "reman" stuff. It is a good brand but you never can tell about "reman" parts. I'd unplug the pickup coil from the module & hook a VOM or self powered test light & move wires & the advance. Test for the coil wires to ground. If it is a "reman" they may not have replaced the pickup coil.
A small vacuum leak like the 3/16 hose to the advance will not cause an engine to die.
George