Oil pressure gauge dead?

[On_the_road]

I have been sorting out the wiring of my 2002 Monaco Signature.   While working on the dash wiring, I noticed that my oil pressure gauge was pegged.   It stayed pegged with the engine on or off, with no voltage to the meter.   I can believe that I must have done something to cause this.   This did work so it is probably my screw-up.

Front:

Back:

Are these meters repairable?   There is no manufacturer name that I can see.   I have looked online for a replacement, but the gold bezel is not common.

Thanks,

Pete.

 

[Tom Cherry]

This is a gauge that has a “clock spring” and the electrical signal from the sending unit is supposed to operate it.  The spring may have become damaged.  Ordinarily, it would be at zero.  Generically, there are two questions.  What pushed it all the way to MAX?  Was that an accidental short that sent too much voltage or did the sending unit fail?  I THINK these gauges operate where the clock spring keeps it at “zero” and then when the sending unit is working, there is a reduced voltage and that energizes a magnetic field and the strength of the magnetic field then starts to overcome the spring tension.  Higher the sending unit voltage, the further it moves….  BUT, when power is removed, the Gauge is supposed to return to ZERO.  If you Google there are a lot of videos on YouTube that explain it.

I would try to get, perhaps from Cummins, the part number for the sending unit…as that was supplied by them.  Then chase down that PN and find the specs on it.  You would then measure the voltage and see if it was OK.  

NOW, since there is NO manufacturing info on it, it MIGHT be part of a Gage Cluster system.  Many of the later coaches used a gage package supplied by Medallion or ACTI (?) or maybe others.   The signal from the various sensors (turbo, engine temp, etc) were wired into a “Box” and then the individual gauges were controlled by a central system.

BUT, typically they were designed to work with Cummins supplied sensors or sending units….thus they work with a specific PN…. 

There are shops that can rebuild or repair older gauges.  Do some googling.  Typically they are called “Speedometer” repair shops….but they work on most gauges as well.  They are like jewelers or “watch makers”.  They can disassemble the tiny parts and fix or lubricate and make them new again.

CAREFULLY look behind the dash and see where the other gauges such as temperature are located.  Follow that wire….or follow the wire for this one.  If it I goes into a “box” or harness goes into a box or enclosure, try to get a name off it.  When Monaco purchased the dash clusters, folks like Medallion supplied all the gauges….so  if you find the box and PN and manufacturer….start there.

Sometimes there are car restoration companies that rebuild gauges to keep them “OEM”.  They could probably work on it.

This is the “macro” explanation.  We have, I think, had folks that were knowledgeable or curious  and they have carefully disassembled the gauge.  A LIGHT tapping on one side or near the cover on the back where the clear plastic is….carefully, might dislodge the clock spring or reseat it so the gauge returned to zero.  BUT…that is a big IF.

Hopefully a gearhead that has rebuilt or restored a muscle car will chime in.

good luck…..keep us posted….

 

[Ivan K]

We had an airplane oil gauge rebuilt by ueinstrument.com. Not cheap but could be because of the FAA certification regulations. They list automobiles and boats too. It was a 2 weeks turnaround. They have a quote request form.

[Gary Cole]

Have you tried giving it a really good whack? If that frees the needle then it really doesn't matter much what it reads. They are so inaccurate anyway that they read either no oil pressure or suspicious that you might have some oil pressure.

[jacwjames]

The oil pressure gauge looks like the one in my 2002 Windsor.

The dash gauges are all supplied by Monaco along with the sending unit. 

I had searched for my gauge in the past, mine is also pegged but I rely on the Silverleaf for oil pressure readings so not a real critical issue.  

But the original gauge is a Beede part # 945257, you might try contacting them and see if they have something that will work.  https://fariabeede.com/2-pages/prod_display.php?calledGauge=2_press

[veraken]

Here is a company that repairs gauges.  Maybe they can help.

https://www.instrumentclusters.com/

[dl_racing427]

On 10/4/2022 at 10:58 AM, On_the_road said:

I have been sorting out the wiring of my 2002 Monaco Signature.   While working on the dash wiring, I noticed that my oil pressure gauge was pegged.   It stayed pegged with the engine on or off, with no voltage to the meter.   I can believe that I must have done something to cause this.   This did work so it is probably my screw-up.

Front:

Back:

Are these meters repairable?   There is no manufacturer name that I can see.   I have looked online for a replacement, but the gold bezel is not common.

Thanks,

Pete.

 

How many wires were attached?

The I terminal should have switched 12v from the ignition switch, G is ground, and S is the lead from the sensor.  The L spade terminal is for the light.
Probably nothing connected to the unlabeled terminal.

Connect 12v between the I and G and see if the needle resets to 0.
Some gauges are floating, and use opposing coils to operate.  Those type have no spring, and will float around when unpowered.
Connecting the S terminal to G should cause it to peg.  Best to use a variable resistor to test.  The ohm range depends on the type of sensor, but is usually pretty low, under 1000 ohms.
 

[On_the_road]

I have decided to get to the bottom of the problem with my oil pressure gauge.   I cut it open using my lathe and a lathe bit ground very narrow.   I wanted to cut a very narrow groove almost all the way through, leaving just a thin section that I could easily break.

Here is the result;

The steel can just slides off;

 

The meter is a moving iron movement.   That means that there are no hair springs like used in mechanical watches.   There are two coils that are wound at right angles from one another.   One coil is from the G (ground) terminal to the S (sensor) terminal and measures 175 ohms.   The other coil is from the I (12 volt) terminal to the S terminal and measures 71 ohms.   The movement is very rugged and cannot be damaged by applying 12 volts improperly.

I tested the meter by connecting a potentiometer between S and G.   When I turned the potentiometer to 0 ohms, the pointer moved to 0 PSI.   When the potentiometer was set to 190 ohms, the meter went to 120 PSI.   Here, the potentiometer is set to 100 ohms.   Thus, my pressure meter is working correctly.

I used aluminum foil tape to close the meter back up.   It will seal the casing against dust and should be thin enough to fit back in the dash.   If the tape does not work out, I will use glue.

The original problem was that the meter was pegged at the maximum PSI.   It did not move with the key on or off.   The reason for this is in the nature of the meter movement.   Without a hair spring, there is nothing to move the pointer when the power is off, it stays in the last position   When the power is on, the pointer will peg due to the 12 volts unless a sensor is connected.   The normal range for the pressure sensor is 0 ohms to 190 ohms.   When the engine is stopped, there is no oil pressure and 0 ohms, so the pointer will move to 0 PSI.   Therefore, my problem is not with the meter.   Either the pressure sensor is bad or the wire going to the sensor is broken.   Now I will have to chase that down.

 

 

 

[Ivan K]

The sender PN should be listed in your manual.  I had to replace mine but it had 0-100 ohm range.