[T3] AAR woes

Jim Adney jadney at vwtype3.org
Tue May 23 06:04:35 PDT 2017


There will always be "suction" on the inlet side of the AAR, even when it is 
fully "closed." That's because these are not perfect valves; there will always 
be some leak-thru.

There is also some amount of leakage from the outside (not the inlet) 
because the sealing of the lid is minimal and there is also leakage up along 
the shaft. All of this is normal.

The way to check them is to close off the inlet hose with your thumb and see 
how much this effects the idle speed. There should be little or no effect if the 
engine is FULLY WARMED UP.

That said, it sounds like I didn't get the calibration right when I did yours. If 
your engine was fully warmed up when you did your tests, the idle speed 
should not fall anywhere close to 260 rpm when you closed off the AAR inlet 
hose. Feel free to send back as many as you want and I'll re-do them and 
return them for free.

I know I've said this many times before, but it's worth repeating: The AAR 
has absolutely NO EFFECT on the car when you're driving. It only effects 
the idle speed. It does NOT change the richness/leanness of the FI at any 
time.

On 22 May 2017 at 21:13, Daniel Nohejl wrote:

> About 2 weeks ago, my idle stopped coming all the way down from the warm up stage. I found that there was a lot of suction at the air cleaner end of the AAR hose and with my thumb over the end, the idle would drop about 150 rpm. I pulled my AAR to see what was up and noted that the adjustment had moved from where I set it to a more open position. This happened to me several times last fall and early in the winter, so after the last time, I used red Loctite to secure the adjusting screw, yet the adjustment still changed. Wavy washer is there. I brought the AAR inside and tested it in boiling water and it almost entirely closes. Still, having adjusted and set this AAR 3 times in the last 6 or 7 months, I figured why not try a new one. 
> 
> On Saturday, I put in another AAR I just got from Jim and I´ll be damned if the idle still wouldn't come down from 1200rpm. With this one, when I pull the AAR hose off the air cleaner and stop it with my thumb, the idle drops about 260rpm to 940. I put the hose back on and ran the idle back down using the idle adjusting screw and re-set the timing which was slightly off. I got it to idle t around 930 rpm. If I pull off the AAR hose, it drops down to about 670rpm so a dip of 260 rpm again which is about the largest drop ITMve encountered with a leaky/non-closing AAR. So do I just readjust this one to a more closed position? IIRC, it was already pretty damn closed.
> 
> Oh, and just for fun, I pulled off the hose from the AAR to IAD and stopped it with my thumb. That stalled the motor. So where is the air on that end coming from? New hose on both ends of the AAR as of Saturday. 

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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