[DeTomaso] Oil Pressure Gauge

MikeLDrew at aol.com MikeLDrew at aol.com
Wed Aug 31 20:36:35 EDT 2016


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
-------------- next part --------------
   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


More information about the DeTomaso mailing list