[T3] cool weather idle hunt

William J catnine09 at dslextreme.com
Thu Jan 12 14:01:10 PST 2017

 The new electronic VR does not have a ground screw tab it's mounted to the 
rear mounting screw . Last year I cleaned all the Gen and VR wire ends and 
studs and push on female connections and even though some really needed it I 
did not read one bit of a voltage increase. Also I had a 5 mv draw and found 
it by removing the red white leads from the reg to the dash wire and still 
there then removed the red/white from the batt to the VR and that was it . I 
called Bosch to ask how the new VR worked yet they had no clue . I wouldn't 
think it should have any draw and do recall the voltage being higher by a 
volt a few years back , I have no idea how the new ones work , I see three 
diodes at the top and a sealed module in the base and don't know if there 
are more diodes inside. You can't see anything the way it's built , there 
are two hex head screws set in plastic insulators that may allow one to 
remove the top cover . All I can think of is the small draw is either a 
leaky diode or the way it works. The ground I have a star washer between the 
mounting on both screws and another between the ground wire loop end and the 
screw. On the new VR the entire top metal case is hot and has special finish 
as an insulator so the top case cannot touch anything metal . I glued thin 
fiber board to the inner wall just in case .

 The rear defrost switch applies power to the relay coil . There is a brown 
wire to ground for the coil ground. I do not recall where that brown lead 
grounds to without looking at it. It could be at the mount screw like the FI 
power relay.

 I have a VDO voltmeter with oil temp and pressure hung under the dash . I 
use my DVOM to check voltage at the battery and my VDO was 2 volts lower yet 
it can be calibrated by a screw which I did and it's old . I wouldn't count 
on a cigar lighter plug in voltmeter to find real voltage readings or even 
this old VDO by old say mid 90's they do not react fast enough . I set 
calibrated mine using a DVOM on the battery engine off then engine running 
for the highest reading yet it's difficult to read 1/2 volt or even a volt 
because of the scale. I have an old analog volt/amp meter which has 1/10th 
volt marks between 0 to1 all they way up to 18 VDC this seems to read the 
most accurate with a very large scale sweep. DVOM's are to touchy .

 I know generators are old school yet an alt can be over heated trying to 
charge a low battery and can't run without battery power . I used to drive 
with the headlamps on and wipers a fm/am cassette with an adaptor to run an 
XM radio through the cassette deck or a portable CD player , As long as 
there was some steady driving on my 7 mile one way trip to work I never had 
issues , It was only when it was complete stop and go traffic when I needed 
to set it on a 2 amp changer on a timer set for 4 hours each night. That's 
were an alt is a better choice. At least with the battery under the seat 
it's not exposed to the heat of the engine so they don't cook .

 I feel most people do not check the cell levels often enough . I murdered a 
few batteries in my 73 not doing so. They call these maint free yet they are 
not , I do miss the 6 caps it was easier to add water batt in place not so 
much trying to pry off the 2 rather large caps.
----- Original Message ----- 
From: "Jim Adney" <jadney at VWType3.org>
To: <type3 at vwtype3.org>
Sent: Thursday, January 12, 2017 12:18 PM
Subject: Re: [T3] cool weather idle hunt

> ***********************************
> When replying, please consider trimming your message. Thanks! :)
> ***********************************
> On 12 Jan 2017 at 8:10, Daniel Nohejl wrote:
>> I feel like the words hunt and lope are getting a little
>> confused.....at least in my head. In my head, a 'hunt' is what I've
>> been describing at warm-up idle, where the speed surges very high then
>> dips down until going away and a 'lope' is the weak/stalling idle I've
>> been describing. Is that the correct application of the terms?
> Yeah, the definitions are fuzzy and probably vary depending on who
> you talk to.
> I use "lope" to describe the situation where the idle goes so high
> that it hits the FI closed throttle rpm threshold ~1400 rpm. That
> shuts the FI off until the rpms drop to something like 900. Then it
> repeats. It sounds much like there's someone on the gas pedal who's
> blipping the throttle every few seconds.
> To me "hunt" means more like a random wandering of the idle speed.
> Could be up, could be down, could be fast, could be slow.
> There's no real idle stabilization in the D-jet system, so the idle
> on these cars is never rock solid stable. Nevertheless, even though
> it's not clear to me what you're experiencing, it's clear that it's
> something out of the ordinary for your car.
> If you didn't have the new electronic VR, I'd suggest that this was a
> sticky VR relay, which happens when they get old. The contacts weld
> and then break free. This causes the generator to go from full on to
> completely off every few seconds. At idle, this causes the engine to
> slow down every time the generator goes full on. This jerkyness in
> the generator causes the generator to jerk on its belt, which rather
> quickly leads to the generator pulley breaking as the belt gets
> wedged down in the pulley groove.
> Maybe the new VRs have a similar fault, but a loose wire at the
> generator or the VR could cause the same thing. '69s were the first
> year that got ground wires on everything, but VW didn't bother to
> connect the ground wire nicely to the VR at the factory; they put it
> under the mounting screw, rather than to the less rust prone ground
> screw. Does the new VR have a separate ground screw? Is the ground
> there secure?
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
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