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Hey guys, I know the vacuum advance should be ported and not to manifold. Below is an old thread regarding the water neck vacuum. If I bypass the water neck and go directly to the carb isn’t the lower connection considered “ported” and not manifold vacuum?
Everett Everett#2390·#2 ·Aug 15, 2017
I think back during the 'Emission Years' one line went to bottom of carb for full manifold vacuum, and other to vacuum advance for controlling the spark timing for reducing emissions during cold engine running.
First of all, your vacuum advance should be Manifold vacuum, Not ported.
If you mean to bypass the thermo-vacuum switch (TVS) in the water neck? There are very few C3s on the road that have a need for any TVSs. Those should be removed and plugged in most (but not all) cases. New England has at least 6 sets of rules to follow, so check with your state.
A vacuum gauge or your finger will do a better job of telling you what ports are manifold vs. ported than an online Camaro forum.
First - thanks for the quick reply. The port vs manifold seems to be up for debate. I use to think manifold, then ported, and now going back to full mani in the carb. I bypassed the tvs on the water neck. I have only 1 left that goes from the b location top left that goes to a component on the intake that is wired green and tan. What’s that ?
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by gaboriar
First - thanks for the quick reply. The port vs manifold seems to be up for debate.
No, there's no debate about it. If you need to pass an emissions test and want your engine to run hot and unresponsive, use ported. If you want the engine to run well, have good throttle response, good idle, good manifold vacuum and run cool in hot weather traffic, use manifold. If you need the papers to read about this, just drop me an e-mail request for the timing and vacuum advance papers.
Lars not sure what’s funnier. Me finding you or you finding me. Yup- I ran into some of your old posts today and completely on board with manifold over ported. Thanks for reaching out.
Bike space - looks to be the TCS solenoid. I ‘m going to delete it and see what happens, every time I turn the headlights on she starts to stall out. Must be a vacuum leak somewhere.
Holy crap I think I found my leak. Didn’t realize it until I relooked at my picture. The facing part of that component should have a vacuum tee. It’s completely missing. Thinking when the headlights turn on its drawing more vacuum in the whole sys and that leak is the culprit. It’s wide ope
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There won’t be in the morning. That is my problem (or part of it). The hose goes to the carb. Ported. Then the other side is just wide open as you can see. Will pull her and cap her at the carb.
I bypassed the tcs and capped the port. Well may not be the vacuum causing the symptoms. I turn the headlights on and she stalls. Then she started to idle ok. After a minute the car started to stutter and the lights flickering. Maybe a ground issue? I can’t complain this stuff all par for the course.without engaging the lights she idles and drives smooth. Haven’t done a ton of diagnostics. I put a vacuum metered gauge in her and she is firmly in the engine ok green zone
The best thing to do to diagnose stuff like that, is to block off everything you don't need (in your driveway, that's everything except the manifold vacuum advance line), then add things back until you find the leak. Be sure to reconnect your brake booster (if equipped) and PCV before you drive anywhere.
Did you get a set of vacuum port plugs?
In the instructions you should have received from @lars will be lots of useful tips to set timing properly, and maximize vacuum at idle.
I pulled some plugs off a stored carb. So I get a little improvement when I pinch the manifold feed to the headlights before the check valve. So probably a minor leak somewhere. I noticed another more specific symptom. The engine only stalls when I use the high beams. Low beams have no effect on idle. Another issue not sure if connected. The driver marker and directional do not come on as runners. They do blink. I tried grounding them to see if that’s the issue. No luck
I’m using the 8202 which should be correct with the MSD dist 8360. My understanding is I should have 12 volts and not use the resistance wire that is for the points style dist.
Ah the symptoms keep changing. Now Car dies on high beam but not low. The doesn’t on high and does on low. I need to do more diagnostics and less typing. I confirmed 12 volts at the coil
Vacuum advance
