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Re: Auxilliary air valve + general tune-up Posted by Gary Stottler [Email]  (#1463) [Profile/Gallery]
(more from Gary Stottler) on Mon, 17 Aug 2009 14:19:20
In Reply to: Auxilliary air valve, Dan Burkert, Mon, 10 Aug 2009 08:16:41 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Larry gave a really good explanation of how the Aux Air Valve works, and I'd say if you can put 12V across it and see the window move as the heating element warms up, then it is good and you can put it back in the system. As far as overall getting the engine to idle properly, here is the "order of go" I would suggest:
1) Set the timing (if I recall it is 20 deg BTDC at 2000 rpm with the vac advance disconnected).
2) Make sure your vacuum advance is working properly.
3) Set the base throttle blade angle (check the manual for the exact setting, but the throttle blade should be just cracked open). This is set with the Phillips head screw/lock nut on the side of the throttle body.
4) Make very sure you have no air leaks or vacuum leaks anywhere in the intake system including air filter (make sure it's clean), airflow housing and boots, vacuum hoses, etc. (even the brake booster). This leak check also includes the hoses to the Aux Air Valve (or your manual air bypass valve - a "choke" really controls fuel).
5) If your car has EGR you should make sure it is not flowing gas at idle, that would indicate another problem, maybe a stuck EGR valve. I don't recommend disconnecting EGR however as that will hurt your fuel economy and give you no benefit.
6) Set the fuel mixture. As Larry says this is supposed to be done with an exhaust CO analyzer, but I also do it by ear - get the engine to run around 1000 rpm, lean it out until it gets rough and then richen it just enough to get it to smooth out.
7) Once all of that is done, the last step is to adjust the warm idle speed. With the engine fully warmed up and all loads off (so don't do it with the lights on or the cooling fan running), adjust the 10mm bolt at the top of the throttle body until it idles at 900 rpm.
Sounds complicated I know, but those Aux Air Valves rarely fail, and I suspect you have something else going on. One possiblity is that the distributor needs an overhaul - almost every one of these I've seen the vacuum and/or centrifugal advance mechanism freezes up with age. You can take it apart and clean and lube everything yourself if you're handy.
Good Luck!
posted by 198.208.25...
_______________________________________ Gary Stottler
, Mon, 17 Aug 2009 14:19:20 <-- Viewing This Message
, Mon, 10 Aug 2009 19:57:30, Wed, 12 Aug 2009 06:52:28, Thu, 13 Aug 2009 06:21:36
, Wed, 16 Jun 2010 21:09:34
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