[T3] cool weather idle hunt

[Daniel Nohejl]

> On Oct 27, 2016, at 2:36 AM, Jim Adney <jadney at vwtype3.org> wrote:

> Has anything been changed on your Aux Air Regulator since last 
> winter? It sounds like it may be opening too soon, but, from your 
> description, I get the impression that this isn't really the problem. 
> Could there be another air leak that seals up as some rubber part 
> warms and becomes more flexible?
> 
> With the engine warm, pull the AAR hose off the air cleaner and close 
> it with your thumb. The idle speed should not change significantly. 
> Is that what you find?

So here’s one from the vault….or at least more than a month ago. 

I continue to have a very annoying loping idle that begins about 2 minutes after a cold start in the AM. I’ve tried lowering my idle speed to around 850 and then to 800 to no avail. I wrote back in October that I’ve pulled the AAR hose off the air cleaner and put my thumb over the end and have found that the idle dips about 75 rpm. I’ve tried spraying around various joints and hoses with carb cleaner and haven’t found anything at all. There was no lope during last winter, spring, or summer. It started this fall and I haven’t touched any hoses, the intake runner boots, or the intake manifolds which I’ve confirmed are tight to the head. Yes, I could just accept it, but I’d prefer not to, especially b/c we haven’t had this issue before. Any ideas?

And here’s another problem in a similar vein. At the beginning of this month, I developed a strange idle problem. The engine would idle normally once warm but sometimes would enter a hunt phase with short and sharp peaks and valleys. When in traffic, it became problematic b/c if the hunting went on long enough, the generator light would come on at the low point. Sometimes, the engine would stall if I didn’t get my foot on the gas quickly enough after shifting into neutral and getting the parking brake on, which is hard to do in NYC traffic while negotiating cabs and crazy drivers.  This would go on for maybe 15 or 20 mins in traffic. Then, out of nowhere, the idle would suddenly go back to normal. After a few days, this issue went away. In the last 2 weeks, it has come back. Tonight, for example, in traffic, the car stalled 6 times b/c I couldn’t get on the gas quickly enough after getting into neutral. Of course out of nowhere, the idle just went back to normal. The other morning, this happened on a bridge over the East River. Not fun and potentially dangerous as some overzealous driver could easily rear-end me! I’ve tried to replicate the problem by pulling on various wires and connectors to no avail. 

There are maybe 2 things I’ve encountered that sound like this hunt:

—when we’ve tried a new MPS and had the AFR gauge plugged in and it was reading very very lean.

—when the idle speed is around 600 and the motor barely runs

Again, anyone have any ideas?