Oil Gauge is pegged above 120 when running

[tomgagne]

I've read several posts regarding this issue and just wanted to confirm the details. There are 2 oil pressure sending units on Monaco coaches of my vintage. One is a cummins part and it sends info to the ecu, any failure of the sensor will force a warning light and possible stop engine. The other sending unit was added by Monaco and it only feeds the dash guage. If the Monaco sending unit fails the guage will have incorrect readings. Are my statements correct? Also where is the Monaco added sending unit located? 2001 build diplomat isc

[BennieH]

Just had the same problem. Sending unit is top right side of the engine when you're looking at it from the top facing the back of the coach. Summit racing has them, it is a VDO 0-160 psi unit. Search the forum, that's how I figured it out. Lots of posts about it. Cost was $45 if my memory is correct.

[tomgagne]

Thanks for the feedback, I ordered the sender unit from eguages.com and hopefully it's easy to spot/find once I open up the hatch.

[tomgagne]

Finally got the time to search for the oil pressure sending unit feeding the dash guage. Easy find right above the oil filter on my isc. I had ordered the sending unit from eguages. Once I found the unit I noticed the wire had broken away at the connector. I replaced the sender unit anyways since I had it. All is working thank you to the people on this site as well as Rex, your old posts are still helping all of us! God rest your soul. Here is the sender unit info
2002 Diplomat
Part 360-004
10-180 Ohms
0-150 PSI/10 Bar
1/8-27 NPT

[TMan59]

I installed the scan guage d and all my gauge problems went away.
My monaco dash guages seem to have a mind of their own.

[bailiff]

2000 ISC Cummins here. About 1 1/2 years ago, we left a campground and the oil pressure gauges pegged. A restart corrected it. A few weeks later, it pegged again followed by a zero reading. I check the oil, full. About 30 miles later, the check engine light came on, as I turned off the U.S. highway, the engine quit. Called roadside assistance, determined it was a sending unit gone bad. $600 later, I was back on the road with a unit that doesn't read actual oil pressure. Seems Cummins now only supports a sending unit reading 55 lbs psi at any rpm.