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StephenNewby · 04-04-2016, 01:15 PM

I have a 2002 Fleetwood Discovery 330hp Cat diesel. Last time I used it (about 1 month ago), all was fine. Today, when I go to use it there is no indicated oil pressure on the guage. Check engine light is not on, down a little on the dipstick, but nothing major. Any thoughts?

**TonyDi** · 04-04-2016, 01:32 PM

Hi Stephen

There could be many issues but the easiest is to check that the electrical connection is good. That the gauge has a good ground. After that it could be a bad sensor. Do all your other gauges work?

StephenNewby · 04-04-2016, 11:46 PM

Hi Tony - Thanks for the response. I have pulled the gauge cluster out and everything seems OK behind there. Thinking that it would be a simple 2 wire gauge..... Not so! I have checked with the ign on and there seems to be power at the red wire to the gauge. All others work OK, so I crawled under the coach and I believe that I have located the sensor high up above the starter side of the motor. I am going to go down to the local Freightliner store in the next day or so and buy a new sensor. Seems the most logical way to go.....

Skip426 · 04-05-2016, 12:16 AM

Welcome to iRV2.
Your Cat diesel , uses boosted oil pressure to make the fuel injectors work ; so without oil pressure it won't run.
I'll ask what chassis your coach is built on?
But at the same time I'll assume Freightliner, and pass along info on testing Freightliner gauges.
Then ask if you have a side radiator, or rear? It makes a difference as to where the oil pressure sending unit is mounted. The sender is mounted remotely due to clearance issues, caused by the side rad's fan motor's, hydraulic pump.
Assuming it's a rear rad the sender will be in the location shown in the diagram below.

EDIT: Sorry I didn't read your second post where you mentioned Freightliner.

Skip426 · 04-05-2016, 08:05 AM

A second thought ; I always have them.

If it's only the gauge that's not working; your not getting an oil pressure warning light or an engine protect light; then the engine ECM must be seeing a reading from the sender, so I'd be 99% sure your problem is the gauge or it's connections.

StephenNewby · 04-07-2016, 10:13 AM

Hi Skip - Thanks for that. I did go down to the Freightliner store and buy a Sending Unit. (Spendy little things!) I have not installed or even crawled back under the coach to remove the old one. I will also check the ground on the gauge before going any further.

Fred Cooper · 04-11-2016, 08:19 PM

Before I spent time installing the new sending unit, I'd swap the leads between the bad instrument and any other instrument on the panel and see if the symptoms move. This is one of the procedures in the document that Skip provided. (all the instruments get all of the data, and simply select what they need).
Fred

StephenNewby · 04-12-2016, 11:07 AM

Thank you Fred - I have just got back to work on the coach and have determined that the connection to the gauge was at fault. I confirmed that the power was good to the red wire and then ensured that the black wire was a good ground. Re-plugged everything and Voila, the gauge works again. Many thanks to all who replied to my quandry. I never opened the package for the sending unit, so I can return to the dealer!