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.

[MichaelU295]

Thank you so much On_the_road 

Your works, measurements, and guidance are so great.

I am able to pinpoint to and replace my bad sensor and not the gauge.  

Thanks,

Michael

2001 Executive 

[cbr046]

@MichaelU295 I'm not sure if we have the same engine, but let us know if that fixes your problem. 

My 2003 ISC is reading hi oil pressure, enough to trigger the warning light.  From my reading Cummins had a batch of senders in early 2000's that prematurely failed without an available replacement.  Their fix was to install a pressure switch, a new harness and re-program the ECM . . . . at a cost of hundreds of dollars.  $400 comes to mind . . . .

If there's a sensor somebody knows about . . . .

- bob

[jacwjames]

Bob, is this the dash gauge reading or ECM reading to some sort of monitor?

The dash gauge is a Monaco install along with the sending unit.  Here is the parts page for my Monaco installed sensor.

Cummins also changed their sensor to a switch which does require software change and will cost ~$450 to do it.  If you go to the Cummins Quickserve site and look up the part it will be superseded to a new part number which is the switch.   But if you go that route and use some sort of monitor (I use a Silverleaf), the oil pressure will read 55psi.  I want to know what my oil pressure is, don't want a dummy light or false reading.

There was a discussion on IRV2 about this and someone posted that you can use a sensor from a 5.9 and it works.  The individual actually bought one and tried it.  I went ahead and bought one to carry. 

Oil Pressure Sensor 4921511 for Cummins Dodge 5.9L 24V 1998 - 2002

See picture

1 Oil Pressure Sending Unit.pdf

[Paul J A]

Paul Whittle, a member on this site repairs  gauges. Don't know if he does oil pressure ones. 

[cbr046]

7 hours ago, jacwjames said:

Bob, is this the dash gauge reading or ECM reading to some sort of monitor?

Both.  ECM is turning on the warning light.  Dash gauge is reading higher than normal.

The baffling part (to me) are 2 senders, one on each side of engine.  Why does it need 2?  One is like in your hand and the other similar to your link, except mine has 2 terminals (both connected).  I'm guessing the 2nd contact is for low press warning (7 psi).

I couldn't find them on my Quickserve site, either one!  Installed by Monaco maybe . . .

- bob

[jacwjames]

Monaco installed the sensor feeding the dash gauge and Cummins for the ECM.  You won't find it on your Quickserve because it is engine specific, in this case a 5.9.   NOTE, I have not tried the part but individual on IRV2 said he did. 

Not sure what pressure would trigger a high pressure warning.  I know that my cold start up the pressure will exceed 60 psi. 

Might be worth getting a gauge and or scanner to see what the pressure it. 

I looked at the Quickserve site and they did have a procedure to check oil pressure regulator.  see attached

Attached is a page showing where the regulator is, looks like right next to oil filter, attached is a page showing where it is, item 14

Also is a picture showing the part & number

 

In my past life working in mining we used Deutz and Cat, but not many Cummins.  We could adjust oil pressure if we starting seeing lower pressure, never saw higher pressure.

When was last time oil was changed????

 

Oil Pressure regulator.pdf Item 14 pressure regulator location.pdf Genuine Cummins Parts.pdf

Edited April 5 by jacwjames

[cbr046]

48 minutes ago, jacwjames said:

When was last time oil was changed????

Too long ago, in excess of 15,000 miles 😮 .  I changed oil & filter last week but only idled the engine.  I'll take it for a drive (get oil hot) soon.  If it still persists I'll look at cleaning the "regulator" and spring. 

Still having trouble finding some of the documents you found (except the regulator).  Finding the "Training" doc is a mystery using Quickserve.

And I should have a scanner . . . . liking BlueFire or ScanGaugeD simply because VmSpc is no longer available. 

Thank you for your advice.

- bob

 

[Benjamin]

4 hours ago, cbr046 said:

...The baffling part (to me) are 2 senders, one on each side of engine.  Why does it need 2?  One is like in your hand and the other similar to your link, except mine has 2 terminals (both connected).  I'm guessing the 2nd contact is for low press warning (7 psi)...

- bob

Exactly, one is a low pressure warning switch, and one is the pressure sender for the gauge. 

Even with an oil pressure gauge, low oil pressure switch, coolant temp gauge, coolant high temp warning light switch, I still have two or three more senders on my engine for the gauges at the back, and something else still? 

For the price of the other sender, I'd try one before checking the oil pressure regulator, but check your wiring harness connector to see if you need to buy a sender with the connector included to splice it in. 

[jacwjames]

I found the info on the regulator by going to the service tab and then looking in the "Symptoms" tab and found the high oil pressure issue, it had a link on how to check and clean.  Found the part number by searching for "regulator". 

If you have a way to check pressure that would be the first thing I'd do. 

[Dave Waters]

I had the same thing on my 2003 Diplomat, gauge went to high and stopped, the mechanic put a pressure gauge on anti showed good pressure, changed the sending unit,  it works good now. The sending unit on the motor 330 cummins was on the right side looking towards the rad, 2 wires.

Edited April 5 by Dave Waters

[MichaelU295]

Hi CBR046,

My engine is ISM500 on a 2001 Monaco Executive.  My sensor includes both signals for G (Gauge) and WK (Switch). I got the same problem as On_the_road.  It pegged full all the time. No dash warning (because the switch side still work).  Without help from On_the_road, I would replace my gauge and still have problem.

Here is what I got from Amazon for quick shipping instead of the original VDO.  It works!

VDO Oil Pressure Sending Unit 0-10 Bar, 1/8-27 NPTF Thread Oil Pressure Sensor

[jacwjames]

What I find odd is that Bob is seeing both a warning light but also a higher reading on the dash gauge.

I know on my coach there are two pressure sensors. 

When I first bought the coach in 2008 the dash gauge was pegging high but no warning lights.  Since I had no history on the coach (no maintenance records etc, I decided to take it to Cummins for a full service and inspection.  I asked them to look at the oil pressure issue, they said that the sensor had been installed in the wrong port, they corrected but since the gauge had been pegged for so long it still reads high.

But at some point during early ownership I got a Silverleaf VMSpc so I had real time readings of all critical info including oil pressure.  I have also set up alarms for low oil pressure, high engine and tranny temp, and low voltage.   I also set up data logging to track 1 minute intervals of engine and tranny temp, boost and voltage as I had trouble with high tranny temps but since have bypassed the internal tranny cooler in radiator and replaced with stand along cooler. 

[cbr046]

I discovered someone had replaced the 3 conductor sensor near the lift pump with the 2 conductor switch + harness. 

I replaced the sensor near the oil filter with VDO 360023 150 PSI Pressure Sender and all is good.  The old sensor measured 17 ohms (should be 10 ohms). VDO 360023 150 PSI Pressure Sender - not as inexpensive as @MichaelU295's $14 Tyenaza sensor but more comfortable with a M10x1.0 vs 1/8x27 NPT threading . . . and VDO branding.  Maybe the metric vs NPT threading is the same . . . maybe not (1.0 mm would be 25 threads / in) 

Thanks to @jacwjames for helping me through the Cummins Quickserve system.

- bob

[jacwjames]

Glad you got it fixed with a reasonably small amount of $$$.  

They've changed the quickserve website quite bit from when I first started using ~13 years ago.  Still have trouble finding things but it is a good resource. 

[Joedarock]

My 2005 HR Ambassador has the same problem.  Gauge pegged high even with ignition switch off.

Does anyone have a picture of what holds the gauge in place, as I'd like pull it out without removing the whole instrument panel.

Joe

[cbr046]

17 hours ago, Joedarock said:

My 2005 HR Ambassador has the same problem.  Gauge pegged high even with ignition switch off.

Does anyone have a picture of what holds the gauge in place, as I'd like pull it out without removing the whole instrument panel.

I would imagine you've done some "heavy tapping" on it . . . .

You might put a volt meter on it (alligator clips work well), start the engine and look for voltage changes at diff RPMs.  This would rule out a problem with the sender permanently pegging the gauge. 

No picture but if memory serves the gauges are held in by a U shaped plate.  The ends of the "U" pinch the gauges against the back of the dash.  Remove two nuts plus elec connections and the gauge can be removed . . . . if memory serves.  This is all done on your back looking up into darkness with no room for hands, arms or elbows. 

Another alternative, depending on where your gauge is located, is to loosen all the dash panel screws and CAREFULLY pry the dash out where you can work on it from above.  You don't remove the entire dash, just enough to get hands in there.

- bob

Edited October 18 by cbr046