[DeTomaso] Oil Pressure Gauge

Tomas Gunnarsson guson at home.se
Thu Sep 1 02:46:33 EDT 2016


I'd think that a light switch is closed when engine is off and open when
engine is up and running.
 
Tomas

<-----Ursprungligt Meddelande----->

 	  	 From: Joseph F. Byrd, Jr. [byrdjf at embarqmail.com]
Sent: 1/9/2016 4:36:10 AM
To: detomaso at server.detomasolist.com
Subject: Re: [DeTomaso] Oil Pressure Gauge 

Just saying....When I google NAPA OP6091, I get a SWITCH. 
You could use a DMM and see if not running you have "open" and once
cranked 
"closed". A sender would have about 70 ohms not running and approaching
0 
running. 

I would still want a mechanical gauge locally. ( I like Marshell's for 
automotive) 

Joe/NC 

-----Original Message----- 
From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On
Behalf 
Of Mike Drew via DeTomaso 
Sent: Wednesday, August 31, 2016 20:37 PM 
To: mbefthomas at comcast.net; detomaso at server.detomasolist.com 
Subject: Re: [DeTomaso] Oil Pressure Gauge 


In a message dated 8/31/16 17 26 15, mbefthomas at comcast.net writes: 


> I'm trying to figure out why I'm getting a pegged reading on my oil 
> pressure gauge.  It will show normal pressure as the car starts, but 
> soon after pegs to the right and stays there.  Everything runs fine 
> otherwise.  I've swapped out the pressure sender, NAPA OP6091, and 
> it's still pegging, so I'm suspecting the gauge.  Anything else I 
> could check? 
> 

>>>Calling Bill Taylor! That is, assuming it's an electrical. You can't 
make that assumption though. 

I *think* I may have stumbled across something. Doing some primitive 
Google research, I confirmed what I thought I knew, which is that the
oil 
pressure gauge works by taking 12V power in, which runs across the
gauge, 
then out 
to the sender unit, which is a variable ground. The reading given by the
gauge depends on the resistance of the sensor unit; this in turn is 
determined by the engine's oil pressure. 

Extremely high readings after a cold start, if they are accurate, mean
the 
pressure relief valve near the pump and filter has probably stuck. The 
engine should be switched off or the oil filter could burst. 

I have a mechanical oil pressure gauge which threads into the hole
normally 
occupied by the electric sender. It is used to 'sanity check' the 
readings on the gauge. It's the first troubleshooting tool; if the 
mechanical 
gauge reads high, you have an engine (or at least oil filter) problem.
If 
it 
reads normally, you have an electrical problem. 

I could mail it to you tomorrow and you would have it by the weekend?
Let 
me know if you would like to try it out. 

Mike 

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-------------- next part --------------
   I'd think that a light switch is closed when engine is off and open
   when engine is up and running.



   Tomas
   <-----Ursprungligt Meddelande----->

       From: Joseph F. Byrd, Jr. [byrdjf at embarqmail.com]
   Sent: 1/9/2016 4:36:10 AM
   To: detomaso at server.detomasolist.com
   Subject: Re: [DeTomaso] Oil Pressure Gauge
   Just saying....When I google NAPA OP6091, I get a SWITCH.
   You could use a DMM and see if not running you have "open" and once
   cranked
   "closed". A sender would have about 70 ohms not running and approaching
   0
   running.
   I would still want a mechanical gauge locally. ( I like Marshell's for
   automotive)
   Joe/NC
   -----Original Message-----
   From: DeTomaso [mailto:detomaso-bounces at server.detomasolist.com] On
   Behalf
   Of Mike Drew via DeTomaso
   Sent: Wednesday, August 31, 2016 20:37 PM
   To: mbefthomas at comcast.net; detomaso at server.detomasolist.com
   Subject: Re: [DeTomaso] Oil Pressure Gauge
   In a message dated 8/31/16 17 26 15, mbefthomas at comcast.net writes:
   > I'm trying to figure out why I'm getting a pegged reading on my oil
   > pressure gauge.  It will show normal pressure as the car starts, but
   > soon after pegs to the right and stays there.  Everything runs fine
   > otherwise.  I've swapped out the pressure sender, NAPA OP6091, and
   > it's still pegging, so I'm suspecting the gauge.  Anything else I
   > could check?
   >
   >>>Calling Bill Taylor! That is, assuming it's an electrical. You can't
   make that assumption though.
   I *think* I may have stumbled across something. Doing some primitive
   Google research, I confirmed what I thought I knew, which is that the
   oil
   pressure gauge works by taking 12V power in, which runs across the
   gauge,
   then out
   to the sender unit, which is a variable ground. The reading given by
   the
   gauge depends on the resistance of the sensor unit; this in turn is
   determined by the engine's oil pressure.
   Extremely high readings after a cold start, if they are accurate, mean
   the
   pressure relief valve near the pump and filter has probably stuck. The
   engine should be switched off or the oil filter could burst.
   I have a mechanical oil pressure gauge which threads into the hole
   normally
   occupied by the electric sender. It is used to 'sanity check' the
   readings on the gauge. It's the first troubleshooting tool; if the
   mechanical
   gauge reads high, you have an engine (or at least oil filter) problem.
   If
   it
   reads normally, you have an electrical problem.
   I could mail it to you tomorrow and you would have it by the weekend?
   Let
   me know if you would like to try it out.
   Mike
   _______________________________________________
   Detomaso Email List is not managed by POCA
   Posted emails must not exceed 1.5 Megabytes
   DeTomaso mailing list
   DeTomaso at server.detomasolist.com
   http://server.detomasolist.com/mailman/listinfo/detomaso
   To manage your subscription (change email address, unsubscribe, etc.)
   use the links above.
   Members who post to this list grant license to the list to forward any
   message posted here to all past, current, or future members of the
   list. They also grant the list owner permission to maintain an archive
   or approve the archiving of list messages.


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