Distributor Cap/Spark Plug Wires

[Otto Skorzeny]

10 deg btdc won't hurt the engine unless you are experiencing engine knock. I have mine set at the factory mark.

Set the timing in the normal way. Disconnect and plug the vacuum advance line. Adjust the idle speed to the rpm required to set timing. After timing is set, hook up the vac advance and adjust the rpm to whatever the book says.

[NicolasB]

Okay, will do that as soon as I can. Thanks!

[NicolasB]

Okay, so I adjusted the timing to 8 degrees BTDC. Did not know that the distributor was going to be very sensitive when I first turned it haha. The rpm is back to around 700 after adjusting the fast idle, but I noticed that it moves between that and 750. I put the vacuum gauge in and saw that the needle moved slightly up and down about 1in/Hg. I adjusted the mixture screws and they seem to not make much of a difference on the reading. I press the gas pedal (in park) slightly/moderately and the car was fine the first time, but after the second try it started to drop in rpm (as if it was going to stall) , then gets a surge of energy. This also happens at a stoplight. It also bucks when I slow down then immediately press the gas (as if the transmission was kicking badly, but I know it’s fine). I believe this is a sign of a lean mixture, but can someone confirm this (don’t think it’s an accelerator pump issue, these problems didn’t happen before I changed the spark plugs (new ones properly gapped) and changed the mixture adjustment)? I also have the issue of it running rich (throwing black smoke) only when I do W.O.T., which is weird if the mixture is “lean” (I fixed the vacuum break for the choke so no more rich mixture on startups). Thanks again and sorry for being a pain haha (I think I mentioned this before in another thread but wasn’t able to completely solve it).

[Tuco]

May be a vacuum leak. There are several vacuum ports on the intake manifold. Both in front and behind the carb. Locate all of them and cap them off temporarily. See how it runs then.

That way you can start to isolate where it is. There are lots of vacuum lines on there.

I had a hard time finding one on my car. The master cylinder had started leaking into the booster. Couldn’t see it from the outside. But when I capped off the port it was hooked to the car ran so much smoother. Sure enough the rubber diaphragm inside the booster was bad.

[Otto Skorzeny]

You can sometimes find a vacuum leak by spraying carb/choke cleaner around various possible leak locations while the engine is running. A change in rpm - usually increase - indicates that the spot you sprayed is the source of the leak.

Spray around the base of the carb, all hoses and conncetions, dizzy advance, trans modulator, etc. Don't forget the vacuum lines to the headlights.

[Tuco]

Also check the front and back of the intake manifold. If it’s never been off the seals could be crusty and leaking.

[NicolasB]

Could these also cause an issue? I checked the service manual and this vacuum switch supposed to be connected to the distributor advance? I’m not sure how to do that if the one from the carburetor directly goes into it. I also clean the filter out once in a while but it always fills up with this dirt/rust.

[NicolasB]

Here is the diagram but I don’t understand it.

[NicolasB]

I also know that there is a vacuum leak in the headlight system (audible hiss and they close when I’m at W.O.T.), but I have no clue how to reroute the lines. My main issue is that I can’t find the remote control valve anywhere in the engine bay. Where would it normally be (I’m not sure if it would be in the same location as a ‘66 or ‘67 Toronado since they have a slightly different vacuum system)?

[Otto Skorzeny]

You're just going to have to trace the lines. I'd start at the reservoir and work your way back to the first check valve. From there it either goes to the remote control valve or the intake manifold.

But, to get the bottom of the engine issue. Unplug whatever's at the manifold and put caps on the stubs and see if that helps your problem. Basically take the headlights completely out of the equation.

If the engine runs better, you'll know you have to find the vac leak in the headlight system. But you might want to just buy a roll of vacuum tubing and replace each section one at a time.

Does the hissing stop or change when you do anything with the headlight switch? The headlight switch miight be where the hissing is coming from.

Also, the heater/air vent control, plenum doors ares also vacuum operated. See if the hissing stops or goes away when you slide the control lever to different settings.