Date: Mon, 7 Dec 2020 22:20:13 -0500
Reply-To: Larry Alofs <lalofs@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@GMAIL.COM>
Subject: Re: Blinking oil pressure light
In-Reply-To: <CAFdLW6=SiLJEENXoO-cPszGdu3rqnCPMtxin8cQQiOTE2xK-iw@mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
Dan,
On page 97.126 of the Bentley Manual, the circuitry for both sensors is
shown. With no pressure the low pressure sensor is a closed circuit; the
high pressure switch is an open circuit. In my Bentley, there are two
different pressures written near the high pressure switch: 1.8 bar and 0.9
bar. The lower value is the correct one. It should switch at about 0.9
bar, about 13 psi. This confusion may be the reason that VW parts counters
sometimes give you the wrong one. The VW supplied sensors I have seen have
the pressure stamped along the edge.
Anyway, a sensor is just a switch that is connected between its body and
the terminal where the wire attaches. Find a way to connect the leads from
your ohm meter to the spade terminal and the threaded end that screws into
the engine. With no pressure applied the low pressure sensor should have
very low resistance, close to the resistance of your meter leads
themselves. The high pressure should show infinite resistance, as if your
meter is not connected to anything.
These results should reverse if you apply a reasonable amount of pressure
(say 20 psi.) to the opening of the threaded end. Depending on how much
equipment you can gather, this may require 3 or 4 hands ( a helper). A
valve stem from an old bike inner tube can be held firmly against the
sensor while pumping air thru it, for example. A one-person approach might
need some small hose and screw clamps. If you want to actually measure the
pressure needed to make a sensor switch, you need a pressure gauge, more
hose and clamps and a tee. A pressure gauge that goes up to 50 psi or so
could also be helpful some day in checking fuel pressure.
Have fun,
Larry A.
On Mon, Dec 7, 2020 at 12:20 PM Dan N <dn92610@gmail.com> wrote:
> thank you Larry,
>
> I have an ohmmeter and bicycle pump... could you please give me
> instructions on how to test the oil pressure sender?
>
> btw.. the instrument cluster has never been touched for many years but I
> don't rule out it went bad... I will check it today
>
> thanks again
>
> dan
>
> On Mon, Dec 7, 2020 at 6:29 AM Larry Alofs <lalofs@gmail.com> wrote:
>
>> VW dealers sometimes give you the wrong sensor when you replace the high
>> pressure one. If you still have the original sensors, try putting them
>> back in.
>> Find the connectors in the engine compartment for both sensors,
>> disconnect them and use an ohm/continuity meter to see what they are doing
>> with the engine off and running at various speeds. One is normally open
>> the other normally closed. See the Bentley.
>> It doesn't seem that work on the engine should have changed the
>> connection at the instrument cluster.
>> With some determination, a pressure meter, an ohm meter, and a
>> bicycle pump, a person can check the operation of a pressure sensor. :-)
>>
>> Larry A.
>>
>>
>> On Sun, Dec 6, 2020 at 8:25 PM Stuart MacMillan <stuartmacm@gmail.com>
>> wrote:
>>
>> > Best to install an oil pressure gauge so you lnow what’s really going on
>> > with this engine. I’ve installed this kit on two vans with good
>> results:
>> > https://www.vancafe.com/KT-9981901-p/kt-9981901.htm
>> >
>> >
>> >
>> > Stuart
>> >
>> >
>> >
>> > From: Dan N <dn92610@gmail.com>
>> > Sent: Sunday, December 6, 2020 4:52 PM
>> > To: Stacy Schneider <vwcrewman@gmail.com>; Stuart MacMillan <
>> > stuartmacm@gmail.com>; Vanagon Mailing List <vanagon@gerry.vanagon.com>
>> > Subject: Re: Blinking oil pressure light
>> >
>> >
>> >
>> > Stuart... I will check the connection on the foil... Thanks
>> >
>> >
>> >
>> > Stacy... I keep the original switch.. it has the numbers on it .. the
>> one
>> > I bought has no number.. I don't think the switch is bad... I'd think
>> > either wrong oil 10W40 instead of 20w50 or as Stuart suggested bad blue
>> > foil... or worse yet the engine is losing oil pressure... but at 5K
>> miles
>> > on rebuild? I am sacred.
>> >
>> >
>> >
>> > thanks
>> >
>> >
>> >
>> > On Sun, Dec 6, 2020 at 4:10 PM Stacy Schneider <vwcrewman@gmail.com
>> > <mailto:vwcrewman@gmail.com> > wrote:
>> >
>> > Did you happen to keep your original switches?
>> >
>> >
>> >
>> > On Sun, Dec 6, 2020 at 10:01 AM Dan N <dn92610@gmail.com <mailto:
>> > dn92610@gmail.com> > wrote:
>> >
>> > Hi all,
>> >
>> > could you please help me to find out why and how to fix this... Thank
>> you
>> >
>> >
>> >
>> > the oil pressure light blinking at idle and at all RPM
>> >
>> >
>> >
>> > Van description: 1989 tintop syncro, rebuilt 2.1 WBX with about 5K
>> miles, a
>> >
>> > lot of peripheral items were replaced at rebuild including the low and
>> high
>> >
>> > pressure senders. Mann oil filter, 10W40 dino oil in winter, 20W50 in
>> >
>> > summer. 10cent (Chris Corkin) oil cooler with fan.
>> >
>> >
>> >
>> > The Problem: The oil pressure light always blinks continuously when I
>> turn
>> >
>> > the ignition on and went away when I started the engine.... until about
>> a
>> >
>> > month ago... it blinks once, (not blinking continuously as before). My
>> >
>> > mechanic said the blue oil pressure sender is bad... so I ordered a new
>> one
>> >
>> > and put it on. And now it blinks continuously, engine running or not at
>> all
>> >
>> > RPM, cold or warm engine... I check the sender wire, looking OK the
>> white
>> >
>> > plastic connector is OK too.
>> >
>> >
>> >
>> > What else to check? Could the high oil pressure sender be bad too? Is it
>> >
>> > safe to drive about 20 miles to the mechanic or get towed to him?
>> >
>> >
>> >
>> > thanks in advance
>> >
>> >
>> >
>> > dan
>> >
>> > --
>> >
>> > 1989 Swedish Tristar with Aluminum gates and Atiwe 16" Wheels.
>> > Oldest son is an Eagle scout.
>> >
>>
>
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