Oil Pressure Guage

[hermanmullins]

IZ NEEDS SUM HEP!!!!!

My oil pressure guage is pegged past 120 psi. I purchased a new guage and installed it. The minute I turned on the key it pegged again. I installed a new Sending unit. Guage is still pegged. I was able to reset the guage with a 9 volt battery. Reconnected it turned on the key and it pegged again. Has anyone out there had a similar problem? How was it fixed? It seems to be sending 12 volts straight to the guage.

PS: New sending unit was a superseded P/N and had to have an adapter cable wired in pin K on the plug.

2002 Monaco Dynasty, Cummins 400 ISL, Allison 6 speed.

:o

[wolfe10]

Herman,

There are so many different sender units/gauge packages that it would be virtually impossible for us to know how yours is set up.

I would start by calling Monaco and asking them how to troubleshoot this problem.

They should be able to give you a step by step process-- may be as simple as disconnecting the wire at the sender and verifying reading, touching that wire for an instant to chassis ground and verifying reading, etc.

Could be the sender to gauge wire grounding somewhere.

Please let us know what you find, so the next person with your chassis/coach will know what to do.

Thanks.

Brett

[hermanmullins]

I contacted Monaco Tech. Service. Was told that the sending unit wire must have a dead short and that the best I could do was to replace(run) a new wire. I said 40 plus feet. "Yep" he said. The wire runs down the chassis rails. I wonder if they make a Bluetooth guage and sending unit. I will try to check out the obvious places where the wire could be grounded. Will let you know what I find.

[wolfe10]

Herman,

If, as the tech told you, that ground on the sense wire= high PSI, before concluding the cause, disconnect the wire from the sender. If the gauge goes to zero, that would suggest that the sender unit is faulty (even though new).

If disconnecting the wire still gives a high gauge reading, he may be correct and the problem is likely in the wiring.

BUT, if you can isolate that wire at the gauge and remove it, you can check with an ohm meter between the wire and ground and also see if the gauge shows zero pressure with the wire disconnected.

Brett

[hermanmullins]

Brett, I was able to zero the guage by using a nine volt battery.

When I connected the guage with out power it stayed on zero.

But when I turned on the key the guage pegs out.

My next try is to remove the sending unit wire from the guage, zero out the guage again and turn on the power with out the sender connected.

If the guage stays zeroed then I will assume the sending unit wire or sending unit itself is grounded.

My next step will be to reconnect the wire at the guage then unplug the wire from the sending unit reset the guage and turn on the power. If the guage still pegs out I will know there is a dead short some where in the wire, however if the guage doesn't move then I can assume the new sending unit is bad.

Do you agree?

[wolfe10]

Yes, I agree. But suspect it may be easier to access the sender unit on the engine. Same diagnostic logic applies-- you are right on.

Brett