[T3] cool weather idle hunt

Jim Adney jadney at VWType3.org
Wed Jan 11 09:46:56 PST 2017

On 11 Jan 2017 at 9:32, Daniel Nohejl wrote:

> I didn't drive the car this morning, but when I got in yesterday
> morning, I plugged the mini voltmeter into the charging port and got a
> reading of 12.5. Since voltage at the charge port has tended to read
> either .1 or .2 volts below the battery, I figured the charging system
> was working. I should still get the battery tested though. 

That's very good for overnight with no loads applied. Your battery is 
probably fine, but, as William says, it's possible, but rare, for the 
battery to have an odd internal problem.  

I assume you've checked all the connections around the engine, 
including on the generator. Also check the tightness of all the 
connections under the backseat: battery, VR, FI power relay. Make 
sure the FI relay attaching screw is tight. Check both ends of the 
battery ground strap. Make sure the battery posts stick up above the 
tops of the battery clamps. Check the wire from the battery + 
terminal to the VR and the + terminal to the FI relay. Don't remove 
and replace those connectors, just wiggle them to make sure they are 
snug. Don't get out the steel wool; it doesn't help and the steel 
bits can cause problems elsewhere.  

The AAR can't open and close rapidly, unless the adjustment screw has 
come loose or fallen out (not good, because you have to wonder where 
it went.) But it can get sticky and not respond to temp as it should.

I'm assuming that you don't hear relays clicking when you have this 
idle problem. If you do, that's a VERY important clue.

Does this problem appear ONLY at idle and never appear to cause 
jerkyness while driving? Seems pretty odd, but this has certainly 
been the "poster car" for odd problems.  

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

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