High idle: air cooled 1980 vanagon, CA

[LordHuron95]

Hello all,

My engine is freshly rebuilt including new hydraulic lifters. After failing smog, turns out when warm my van idles up to ~1300. I used the adjustment screw but it only brought the idle down between 100-200. This was all after I had set timing to 7.5° btdc.

I've been scouring the web with lots of dead end posts or ones that go in a seemingly different direction. So far I have found and fixed many little vacuum leaks, including a new gasket on the cold start valve, a new "s" boot and tightening the bolts holding the throttle body on. Only leak I know of left is the usual one on the top of the throttle. I've tested the AAR, the deceleration valve and the vacuum canister on the distributor. My findings for each below.

Auxiliary Air Regulator (AAR)

Book says: while cold, start the engine and feel for vacuum and the engine speed should decrease (it did not noticeably change)
As the engine warms up, the vacuum should disappear. (It lessened but did not totally disappear.)
I then tested resistance as the book says to do. Should be 30 ohms, mine read 30.5

Decel. Valve (DV)

Book: dissc. Hose between DV and intake sensor. Start the engine and rev to 3000 rpm for a few seconds then release suddenly. With finger on end of hose, vacuum should be felt. (I think I felt it but it was very very slight.)

Also, I had seen a post regarding the vacuum can on the dist. Said that to test it, suck on a hose for each end. Advance and retard. Both should hold vacuum/pull on your lip or tongue. In my test, both did hold vacuum.

Looking for what to test moving forward, and advice on the information I've shared so far.
_________________
Never swing a mean loop. Never do dirt to man nor animal.

-1980 Vanagon Westy

[Wildthings]

Set your timing at 28° BTDC @3800+ rpm, hoses removed from the vacuum canister and plugged, and the DIS (Digital Idle Stabilizer) bypassed. This should get your timing to spec without having to worry about your idle speed being incorrect.

The DIS and the retard function of the vacuum can work together. You also need to make sure the throttle switches are adjusted right.

The throttle valve will wear with time as well, so check the classifieds for someone who rebuilds them.

[LordHuron95]

[Wildthings]