Re: [alfa] Oil Pressure gauge

["skippatnode" <skippatnode@xxxxxxx>]

Dave,
    The direct reading gauge is a good idea to make sure you are getting oil
pressure!
    Now, let's try a couple more things:
    First, with the engine off and the ignition turned on, pull the wire off
the pressure sender.  The gauge should read Zero.  Then touch the wire to
ground and the gauge should to full scale.  Unless you have an intermittent
loose connection or bad wire, this should tell you the gauge is OK.
    Second, leave the gauge wire disconnected and connect an ohm meter to the
sender.  With your direct reading gauge attached, start the engine and go for
a drive long enough to get the oil hot and the oil pressure to drop and
stabilize.  The resistance on your ohm meter should vary right along with your
direct reading gauge as the engine RPM goes up and down.  If it doesn't and
jumps all over the place, the sender is bad.
    Nothing against IAP.  Senders are mechanical, variable resistors and even
new ones go bad.
Skip Patnode
67 Duetto
Norfolk, Va


Date: Tue, 21 Oct 2003 08:36:05 -0400
From: "Dave Martin" <dwmartin@domain.elided>
Subject: [alfa] Oil Pressure gauge

Dear Alfisti -
I could use some help diagnosing an oil pressure gauge problem on my 87
Spider.
Yeah, those things.
It reads all over the map - sometimes below 0, sometimes (just a minute
later) about 20, then back to 0, etc.  It used to be always about 87 until a
year ago when it first started acting up by suddenly starting to read
extremely high - almost pegged.  But then I replaced the sending unit (IAP
part) and it's still crazy, now reading only low numbers, that are never the
same.
A while ago I temporarily T'ed into the idiot light a mechanical gauge and
read pressure about 80 psi, the idiot light never comes on, the temp is
good, the engine sounds okay, and its been driven for months like this
without self-destructing, so it would seem that the actual oil pressure is
"okay".  But seeing low, fluctuating numbers on the gauge is a bit
disconcerting.  The fluctuations make me think that there is an intermittent
electric connection somewhere and all I need do is to clean it, but the book
isn't too helpful in identifying where the connections might be.

Anybody have any suggestions?

Dave Martin
87 Spider Quad
Endwell, NY
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