1978 blazer dies when put in gear

[Mikeymike383]

What kind of other history are u looking 4

[Irish_Alley]

The vacuum advance could be leaking. Where do you have it plugged into? Did you unplug it and see if the rpms change?

[Irish_Alley]

Did you set the  timing after the vacuum cange? Is it a new distributor ?

[blazer74]

It was running fine, changed the vac can and the problem started.
Really doesn't make any sense to me.
How long have you had it?
What was/is the idle rpm neutral and in gear?
Advance hooked to manifold or ported.

Only thing that comes to mind is mechanical advance coming in too soon at idle and when placed in gear mechanical advance drops out causing idle to go to low and stall.

[Mikeymike383]

I had it 4 3weeks. And I was going threw fixing the lil problems& doing a tune up when I realized the vac adv didn't work at all so I changed it out with a new one and my buddy said we needed to retard the timing on the dizzy. It's plugged in the carb. It's a 1973 Buick quadrajet. If the mech adv is dropping causing it to stall how do I go about fixing this problem?

[Mikeymike383]

And no it's the same dizzy that was in it when I got it

[Irish_Alley]

whats youre base timing at now?
most of us op for 12° and do manifold vacuum (manifold vacuum isnt limited to just the manifold, the carb should have a port on it for manifold vacuum also)

[Mikeymike383]

I don't know off hand what my base timing it at now. The Buick quadrajet only has 2 vac ports on it 1 on the side net 2 the choke(left) and on on the bottom or base of the carb. We have it hooked up 2 the one on the left side. I can't find a vacuum diagram 4 that carb so I can know where it goes

[blazer74]

You need a port that has constant vacuum at idle. (Manifold  vacuum)

When idling in neutral pull the  hose off going to the dizzy And you idle speed should lower.

Put you finger on the port and see if there is vacuum. Use a vac gauge if you have one.

No vacuum means ported vacuum (no vac at idle) This is assuming your at a normal idle speed range.
 
Any idea what your idle speed is in neutral fully warmed up engine with choke full open.

You should be able to change idle speed by applying vac or sucking on the hose to the vac advance can.

This may be carb issue also but basics first.

Get some one else to help and partially hold the choke flap closed and see if it runs that way. BE super careful and stand to the side. 

[Mikeymike383]

Ok I'll check this out tonight when I get home. So the vac adv needs 2 b hooked up 2 manifold vacuum

[blazer74]

I prefer it that way

[blazer74]

Ported came along with emissions.

[Irish_Alley]

not that it "has" to but for emissions it should be but for performance we all prefer manifold

[Mikeymike383]

Now let me ask this if it's a carb problem what could it be

[Irish_Alley]

vacuum leak/improper tune