Date: Wed, 26 Dec 2001 14:12:46 +0100
Reply-To: Raimund Feussner <rfeussner@GMX.DE>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Raimund Feussner <rfeussner@GMX.DE>
Subject: Re: # tachometer ideas
Content-Type: text/plain; charset="iso-8859-1"
The RPM signal is on PIN#7 of the 14-pin instrument connector. Green wire.
I guess itīs a 12Volt signal. Itīs from PIN#1 of the coil.
But why build all these LED monitors?
Use a tachometer: one look and you know all you have to know. 2K, 5K,
overreving is not possible with the digifant injection system because it
shuts off the injectors at high RPMs. Also, I think "drive-by-ear" is still
the best. I think one can hear if the engine runs too high, too low or when
itīs time to shift.
I really like these electronic toys too watch, hear etc. But why build all
these tools (consuming time to develop etc.) when one thing works for all
purposes? As you said, no need to reinvent the wheel...
And thereīs really no need to be frightened of the vanagon engineīs
condition. Some of you are too hysterical, arenīt you?
No criticism from me, I am a hysterical, too. But Vanagons run and run and
run...
The low-line vanagons in Germany run for 15 years and more with no "big"
servicing (some oil changes, thatīs all).
Just my 02 cents from the Vaterland...
Merry X-MAS
Raimund
----- Original Message -----
From: "TinkerMan" <tinkerman007@YAHOO.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Wednesday, December 26, 2001 11:52 AM
Subject: # tachometer ideas
> Hello Volks,
>
> The wasserboxer engine system has several RPM related
> thresholds, e.g. the ECU is also RPM driven (along
> with a whole bunch of other monitored parameters), as
> well as the dynamic oil pressure monitoring system
> (DOPMS) (which has a built-in 2K RPM threshold.
> Moreover, the DOPMS uses a wire coming from the motor
> to the dash cluster with RPM data (pulses from the
> coil?) for monitoring the engine speed and sounding
> the buzzer if low oil pressure occurs above 2K RPM.
> This same signal is probably used for the tachometer
> if installed.
> My 1990 GL doesn't have a tachometer, and I don't want
> to replace the instrument cluster as some suggested.
> Does anyone know (or has a working solution) of a
> simple way to:
>
> 1. Monitor some signal in the engine (not so good,
> will have to route a wire) or instrument cluster
> (prefered) and derive from it RPM data (possibly with
> a simple external circuit) for display via a few
> simple LED's or for alerting purposes with a buzzer
> (e.g. over-revving the motor). I'm not talking about
> full blown tachometer, but rather a simple indicator
> for some RPM important (e.g. 2K or 5K).
> A example of a simple method I could think of would be
> to insert a switch in series with the high (0.9 bar)
> oil pressure switch. Disconnecting it over 2K rpm
> (with the switch) would sound the built-in buzzer of
> the DOPMS and serve as a 2K RPM indicator. Now how to
> do the same thing without all that noise and no
> switch?...;-)
> Maybe there are other RPM related signals out there
> that could easily monitored with LED's?
>
> 2. A simple Tachometer circuit that interfaces with
> the standard dash RPM signal. I'd prefer a small,
> electronic one with either a LED for each range (e.g.
> <1K, 1-2K, 2-3K, 3-4K, 4-5K etc.) or a small LCD
> circuit (oops, no! LCD displays might TOAST due to the
> heat from the sun on the dash) or LED display. Again,
> simple is beautiful...(and also, good things come in
> small packages...). Not a large, mechanical one. Maybe
> a Frequency-to-Voltage (F->V) circuit that can be used
> along with an analog meter (also used with the famous
> DIGITOOL ECU analyzer?).
> I know it's doable, but why re-invent the wheel? Heck,
> I'm sure there's even a cheap kit for this available
> (either F->V or direct LED output)?
> As far as I've seen, some signal conditioning must be
> done on the tach signal as I suspect it's not a low
> voltage if it's coming from the coil.
>
> 3. Any other interesting ideas on the subject?
>
> **if possible, please send me a copy via p-mail too
> since I often miss responses on this very active list.
>
>
> =====
> Cheers,
> TinkerMan
>
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