[T3] my long term issue have to unplug TS1 for a smooth idle.

[Jim Adney]

On 30 Sep 2019 at 16:01, William Jahn wrote:

> The only way to really know is pull the hose from the IAD to the AAR
> and look before I start it. You can only see the slot from the IAD
> side. 

You could do that, but that would be the hard way. The easy way would be to 
start the engine and remove the hose that goes from the air cleaner to the 
AAR. Leave the AAR end attached.

Then block off the end of the hose with your thumb. If the idle changes 
significantly, it means that less air is getting thru the AAR. The amount of 
idle speed change will give you an idea of how far the AAR is open.j

Just do this at the different stages of the warmup idle speed change, so you 
can tell what the AAR is doing at each point.

> The entire point of the AAR is to be a vacuum leak to only richen
> the mix by causing the MPS to keep the injectors to stay open a bit longer
> along with TS2 and partly TS1.

No, while this belief, or the opposite, gets repeated often, it's not true. If 
everything is working correctly, the MAP sensor compensates for the extra 
air and corrects the mixture. AAR open or closed, the mixture should be 
approximately the same richness.

As you said, it's a vacuum leak, just like the idle adj screw, which also does 
not have any effect on the idle mixture.

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