Date: Sun, 27 Jan 2013 13:10:14 -0800
Reply-To: Ryan Press <ryan@PRESSLAB.US>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ryan Press <ryan@PRESSLAB.US>
Subject: Re: Ignition Switch "Su" Power
In-Reply-To: <CAB2RwfgadUpZOmsXQQS9Fra+oSFGMV-DyaKxiOimkn9aDvc+nA@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Hi Neil,
I think it would help if we knew how much current the ECU actually draws,
and how much the coil draws. Can you measure these with an ammeter both
while running and not? Did you add this relay/wiring because you actually
had problems or because you thought there could be problems?
The way I was thinking of adding the resistor to the coil would be in
parallel. It would load the circuit at all times, but the coil would still
see pretty much the same voltage when energized. It would be a kludge; I'm
sure there's a better way.
Ryan
On Fri, Jan 25, 2013 at 11:08 AM, neil n <musomuso@gmail.com> wrote:
> Very good points. Much appreciated.
>
> This morning, I realized that yes; Su as an ign. switch was a bad idea.
>
> I think someone posted this idea a while ago, but I too wondered if a
> surge protected relay would suffice. Or as you suggest, use a resistor
> somehow. Seems the surge protected relay would be best. If not.....
>
> If a resistor was wired in parallel across 85-86 of the relay, would
> this added resistance only affect that circuit once the coil is
> de-energized? i.e. does that added resistance affect the coils ability
> to keep the switch closed when in use?
>
> My electrical knowledge is made up of bits and pieces, so apologies if
> I'm asking questions in a poor way.
>
> Thanks
>
> Neil.
>
> On Fri, Jan 25, 2013 at 10:43 AM, Ryan Press <ryan@presslab.us> wrote:
>
>
> > Back on topic, I would think a strategically placed diode somewhere would
> > keep the relay from staying on with the ignition off. If that is not
> > possible perhaps the brute force method of putting an additional load
> > resistor across the relay's winding would do it.
> >
> > Powering the engine with just the key in is dangerous. Consider this
> > scenario which has happened to me before: Going down a large hill my
> > throttle cable was frozen with ice at part throttle. I was able to
> leave it
> > in gear and turn the key off, while maintaining all normal functions,
> until
> > I was able to find a pull-out. If I would have needed to remove the
> key, my
> > steering would lock, and I would end up over the hill. The other option
> > would be to pop it in neutral, but then the engine would be bouncing off
> the
> > rev-limiter.
>
>
>
> --
> Neil n
>
> 65 kb image Myford Ready For Assembly http://tinyurl.com/64sx4rp
>
> '88 Slate Blue Westy to be named.
>
> '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
>
> Vanagon VAG Gas I4/VR Swap Google Group:
>
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
>
|