idling problems, Running problems, PROBLEMS

[MustangSix]

Is the advance hooked to manifold or ported vacuum from the carb? That could account for much of the rpm drop.

If you have hooked the DUI to full manifold vac, it would be the vacuum advancing the timing to the 10 degree mark at idle. As soon as you put in it drive and the vacuum drops, the advance falls away and your timing in park is now probably only 4-5 degrees, maybe less. That would make the engine stumble as soon as you put it in drive. If you are using manifold vac, you have to time the engine with the vacuum disconnected.

 

[mach1 mark]

Had the same problem, all I can say is, timing and power valve. Buy a Holly performance manual and read it about two or three times, it will give a few clues to the problem . I don't think its the cam or torque converter. Connect the vacuum to port if that doesn't work try the manifold. It took me a while to fix my same problem. Buy the book.

 

[gtm1086]

Something to try. Disconnect and plug the vacuum going to the distributor. Set the timing to 12 degrees then try putting it into gear with the vacuum advance disconnected.

 

[jim reese]

This weekend I spent some time working on my car.

I changed where the vacuume from the carb to the dist was connected and that seemed to help.

however my question is this:
On the number six intake runner there is a bung that has a nipple threaded into it. It is split and one hose runs to the transmission and the other runs over to the power brake booster. Does that sound correct? or should it be plumbed differently?

My other question is the nipple that is on the base of the carb or the spacer is plumbed to the PVC valve? Does that seem right or should that be used to connect the power brake booster and the transmission line?

Would it hurt anything to just plug the PVC hole since I have a vent in the front of the valve cover?

Thanks for any suggestion.

Jim

 

[BIGREDRASA]

Normal placement for PCV vacuum is the carb spacer/adapter. Try capping every vacuum port one at a time. Tranny, brakes, PCV, Dizzy. That can help rule out each item.

 

[66 Fastback]

Tony has a good point. I once had a vac leak in the transmission vacuum modulator and another car that had a leak at the Brake power booster. Plug those lines and see if anything changes.
Doug