Date: Thu, 1 Oct 2015 13:30:36 -0700
Reply-To: vw_van_fan_Mark <madvws@COX.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: vw_van_fan_Mark <madvws@COX.NET>
Subject: Re: Oil Buzzer advice
In-Reply-To: <AE4CBDAA-ABF9-404D-B49A-587939E4D257@gmail.com>
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That problem comes down to 1 wire in the dash cluster. The yellow wire,
to the 14 pin connector. If that yellow wire is broken or not making
contact in that connector then the oil alarm/buzzer will happen every
time the engine rpms get over 2000.
The oil warning circuit board also gets tach pulses and when it sees
rpms at about 2000 or more it then looks for pressure indication on the
second oil switch. If it doesn't see that indication it sounds the
audible alarm and flashes the led.
There are 2 oil switches. The second switch works backward from the
primary switch. The second switch sees an open condition until oil
pressure rises to about 10-15 psi and then the switch closes and
connects to ground to signal good pressure. When the wire to the switch
is broken or not making good connection that grounding never happens.
The cluster oil warning circuit board expects to see that grounding
whenever rpms are above 2000. Otherwise the alarm sounds.
Mark
Aaron wrote:
> Hello all.
>
> We have a ’91 automatic that is currently giving us an oil buzzer warning and I think it may be a false alarm, but perhaps not.
>
> History:
> • 200,000 miles. Original engine.
> • Has occasionally given the buzzer when on hot, long trips coming off freewa.. Typical vanagon. Not too concerned
> • 3 weeks ago oil cooler seal failed pumping 2.5 quarts out the back over about a mile & leading to an oil buzzer, immediate shutoff, and a short tow home.
> • That was fixed and the van has driven fine since then. No oil buzzer
> • 20w50 and Mahle? filters.
>
> So, one might ask “Where there any unusual events that might trigger this sudden oil pressure light?”
>
> As usual…probably me. Over the weekend, I started finishing the brake work which means a new master cylinder and rear brakes. I swapped out the master cylinder, put the dash back together, and took it for a spin. Oil buzzer went on as soon as I started driving it up the road. I stopped it. started up again, and same thing. Oil light comes on once I rev past 2000 or 3000 (can’t remember) RPM’s. Due to the fact that things were fine BEFORE I tore apart the dash, it might indicate that perhaps there’s gremlins in the electrical.
>
> I did some checking and my hope is that this is because of an electrical issue related to my “handiwork” on the brakes. I cleaned the contacts at the big plug where the oil pressure sender wire is with no change in the behavior. All contacts look good anyway. I was careful with the dash bits and hopefully didn’t damage anything.
>
> If this is indeed electrical, are there “typical” issues that can help me to diagnose whether the warning is an electrical issue or actual oil pressure issue? Please don’t answer “get an oil pressure gauge”. I’m hoping for some multimeter readings etc...
>
> Meanwhile we drive the spare.
>
> Thanks!
> Aaron
>
> ’91 Carat (daily driver)
> ’87 Westy
>
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