fluxuating oil pressure gage

[batman69]

Turn on key to start engine. Oil pressure gage bounces from 20 to 40 and back....alarm comes on and chk eng light comes on....can start engine and runs fine......disconnected oil sending unit. Same symptoms.. 2003 Dutch Star...Cummins 350 ISC on Spartan Mountain Master Chassis.....ordered new gage thought was only thing left....plugged in new gage same story.....am hearing eng may have 2 sensors for the oil....can't find but 1.....Called Spartan. They said had heard of such a thing....Talked to Cummins said on had 1 oil sensor listed....Help and Thanks.....

[Bikeboy57]

Can you clarify if the gauge fluctuates with key on engine off? And key on engine on?

The fact that it fluctuates with sender disconnected has me checking the ground on the gauge. Run a new ground wire to a chassis point and see if that changes the behavior.

[Robbie_Welch]

I had a similar problem. Gauge started acting up. I replaced the sender and couldn't get the gauge to read correctly (not the correct sender for the gauge). I couldn't get a matching gauge for the sender during the pandemic so I replaced it with a mechanical gauge located in the engine compartment and mounted the backup camera to view it. Works awesome. I may leave it that way even after I get the electrical gauge back in.

[Stim]

The first thing I would do is "T" in a mechanical gauge and mount it somewhere in the engine bay to confirm problem is not the engine.

[Ivylog]

I would look into a Silverleaf monitor... probably less than taking it in.

Silverleaf

[batman69]

Thanks Haste Maker... looks like getting there with everyones help..Have a great day...

[haste_maker]

Be best to take it to a Cummins shop, some of their engines use a oil pressure relief value that is inside the engine & they will know how to check it.

[batman69]

Sending unit disconnected...same symptoms ..thanks

[batman69]

Rgr on trip to shop....trying to avoid but....seems to be in my future....thanks

[enblethen]

Could be defective sending unit

[Lwiddis]

That’s what gauges are for...a warning.

[2oldman]

A fluctuating gauge may need a trip to the shop.