Date:         Wed, 14 Dec 2005 12:34:09 -0800
Reply-To:     mark drillock <drillock@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         mark drillock <drillock@EARTHLINK.NET>
Subject:      Re: New instrument cluster in '84 Vanagon
In-Reply-To:  <6da579340512140906q3cde334dl92b52a483f90ee19@mail.gmail.com>
Content-Type: text/plain; charset=us-ascii; format=flowed

Actually, it does not work quite the way you say. The dual oil switch
circuit board never ignores the low pressure switch. It does ignore the
high pressure switch when the engine is at lower rpms, below 2000 or so.
Above that rpm it watches both switches and blinks the LED if either has
a bad reading and also rings the buzzer if it is the high switch with a
bad reading. As for a gauge being preferred to an idiot light, no way. A
good supplement perhaps but not a substitute. I have had my engine saved
by the blinking light. Traveling on the freeway one night with my SO
driving, she says "what's this blinking red light?" I lean over, look,
and yell pull over! I get out and find oil dripping off the back of the
Van and no oil reading on the dipstick. A valve cover gasket was leaking
on one side. Not a big leak but enough to drain the engine after a few
hours of highway driving. I had checked the oil level at the last fuel
stop and it was fine then. Do you think she would have noticed a low
pressure reading on a gauge in time to save the engine? No way. A
suddenly blinking red light, yes. I drove that engine for many years
after that event.

As for disabling the tach feed when using the later cluster there is a
better way than cutting a trace. Simply bend the male pin over a few
millimeters. So the connector misses it when put in place. There are 6
pins in the connector on the back of the speedo, a group of 2 and a
group of 4. The outside pin of the group of 4 is the tach signal to the
oil warning board. Bend that pin to the outside and push the connector
back on the remaining pins. Then only the low pressure switch will be
monitored.

Mark

John Bange wrote:

>
>
>Well, ideally you'd want to go in and cut the trace feeding the tach signal
>to the "dynamic oil pressure sensor" circuit board. Above 2000RPM the board
>ignores your .3bar sensor and just watches a ground loop where the .9bar
>sensor should be. Cutting the RPM signal to the board would make it think
>you were always below 2000, thus keeping your .3bar sensor "in the loop" all
>the time. Realistically though, it shouldn't matter. If your oil pressure
>drops far enough to trip the .3bar sensor when you're above 2000RPM, the
>light is essentially a "pull over and swap engine" signal. I mean, maybe if
>the pump was sucking air because of a major leak blew all your oil out you
>might be able to pull over before your engine goes feet up, but more than
>likely not. The idiot light is better than nothing, but not much.
>Personally, I think an oil pressure gauge is the only really sure way to
>know when things start "heading south". The Vanagon oil light reminds me of
>the TEMP light in my awful 82 Olds Cutlass-- it really should have been
>labelled "THAR SHE BLOWS".
>
>
>
>
>--
>John Bange
>'90 Vanagon - "Geldsauger"
>
>
>
>