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What makes me suspect the AAR is not adjusted correctly is that when I had it out on the work bench - it was room temp (68ish) and yet the spring seemed to be applying pressure to close the valve - not open it. This seems opposite to what it is supposed to do - open when cold, close when hot. I did that hose-pull test...when engine warm I pull off hose to the air cleaner and no engine RPM change which is good. You're right - I still feel some suction but not much and plugging the hole to the AAR makes no change. The decel trick did work to clean out the rich cylinders so that is good. Martin at the DDB is going to work on it for me Friday - perhaps I have some faulty sensors and/or low voltage from the regulator. More to come - thanks for the great info...I'm learning a lot! Paul > On 28 Apr 2004 at 3:58, type3@comcast.net wrote: > > > MY ASSUMPTION: The AAR is spring loaded valve that should be adjusted to > > open and allow more air when cold - right? - this would raise the RPM until > > the hot oil warms the spring and closes the air valve - lowering the RPM to > > normal > > That's correct. It's a thermostatic air valve. > > > My valve was pretty dirty so I washed it out real well...but it does not > > appear to be adjust correctly. I noticed a + and - sign on the bottom near > > the heat activated spring. I could use some advice as to how this thing > > should be set when cold so it behaves correctly. Looks like the screw at > > the bottom lets you adjust the spring to load it for tension when cold - and > > heat expansion would close it. How to do this? > > What makes you suspect that it's not adjusted right? There's some oil temp at > which the valve is supposed to be completely closed. I think that's how it > would have been originally calibrated. I can look up the temp if you like, but > yours is likely to be fine. The functional test is to pull off the hose to the > air cleaner when the engine is warm and then close off the opening to the AAR > with your thumb. If the valve is "fully closed" the engine RPM will not change. > Don't worry about the fact that you'll still feel suction on your thumb; the > AARs never seal tight enough to avoid that. That's perfectly normal and no > problem at all. > > > Is this worth the effort or is it possible that like yours - the air intake > > sensor replace will fix some of this and the AAR does little? > > IIRC, the "problem" was rough running upon first cold start. I think it's > likely that nothing will make this go away completely. Have you tried the decel > trick I suggested to clear out the excess fuel once you get under way? > > > I checked my brain - bunch of numbers followed by B. > > Okay, that's the good early brain. > > -- > Jim Adney > jadney@vwtype3.org > Madison, WI 53711-3054 > USA > > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org >