Fuel Gauge

Got the new sending unit installed this morning. As the tank is currently full, I won't be able to truly test it until I hit the road in Feb. What I can report is being full, it is showing the equivalent of just over 1/16 past full. It's been a couple of years since it worked right, but I seem to recall full used to be more spot on than that.

As long as it is accurate on the bottom end is what is really important. The new units from Centroid are micro-controller based and are not field-adjustable, but can be adjusted at the factory they say. These also have some logic in them they call "AutoCal Full" that uses "Full Detection" at each fill-up. Will see how that works over time....

I sent my test results to Centroid. They got back to me same day saying that the results were consistent with the gauge being pegged past full and that the wiring and gauge were likely fine. The voltage across the two aluminum tubes that go into the tank was too high, indicating to them the voltage regulator in the sending unit had failed. Will get a replacement sending unit ordered after the holidays - their business office is closed this week.

Finally this weekend started looking at my sending unit - doing the testing suggested by Centroid. The next step is to remove it from the tank. I have taken out the 5 screws, but it won't even budge when I try to twist or rock it. Is there any secret to getting it out without messing something up? Like gently twist with some channel locks?


NEVER MIND!

I got it. Just slight pressure with a pipe wrench is all it took to break it loose.

While I am at it, thought I'd post a couple of pix...

billseal wrote:
Replaced sender and used rig this past weekend; all worked well. Thanks to all who replied. This problem is solved; now if I can get jack fixed I'll be good to go again. BFS

WOO-HOO! Thanks for the update billseal!

I still haven't found the time to crawl under there and take a look, but I look forward to getting this fixed.

Replaced sender and used rig this past weekend; all worked well. Thanks to all who replied. This problem is solved; now if I can get jack fixed I'll be good to go again. BFS

I don't know much about DP's, I'm still on my first gasser, but I have been told my 75 gallon tank is only going to fill 80% due to the filler neck joining the tank on the side, not the top. Also due to the air bubble.
When gassing-up after running on fumes, I can tip the rig toward the passenger side with my left rear jack and force feed it up to 65 gallons, but that's about tops. a 150 gallon tank might top-out at 120+ under the same conditions. Just wanted to mention it.

The sender on my 2005 HR Ambassador is on the driver's side.

The Centroid sending unit in Monaco coaches are adjustable and often, just readjusting solves the issues you are having. The sending unit is mounted on the driver's side and as stated, the side panel hinges up for easy access. (On a side note, I removed the screws and added locking clasps to the under side of both fuel door panels. I use the area above the tank on both sides for storage of items I rarely use like tire chains and a blue tank).

There are some adjustment screws on the top of the centroid unit along with some wires that are held on buy nuts. Clean the wires and make sure the nuts are tight. One of the screws is for the empty tank adjustment and shouldn't be touched. There is another for the FULL tank adjustment. This one should be adjusted with the tank full and the coach on level ground.

Clean the adjustment screws with chemical like Goof Off or Goo Gone to get rid of the undercoating that Monaco sprayed on everything. I found on my coach and others that if you adjust the FULL mark to where the needle is about an 1/8" past the FULL line, this gives you a fairly accurate reading of your fuel.

Each time the adjustment screw is turned, you need to turn on the ignition and wait 30 seconds for the unit to stabilize and then check where the needle has moved to.

I adjusted my sending unit when the coach was new. About 5 years later the unit became irratic. I called Centroid and they told me that it was likely that the sending unit had algae on it. I knew this wasn't the case and I readjusted the unit again. It has worked fine since. I think Centroid is too quick to tell people the unit needs replacement.

BTW, billseal - what side of the rig was your sending unit on?

grumpy1 wrote:
I don't want to hi-jack the thread but I have a similar problem on a 2003 American Tradition. My problem is the specifications say I have a 150 gallon tank,the gauge seems to work correctly but when it registers empty I can only put in about 100 gallons, never more than 104 and usually 90-100.It has been this way since we got it 4 years ago.It may seem like a small problem but knowing I could go another 200- 300 miles could be the diference in making it to a state with less expensive fuel.

But you did hijack the thread that I half-hijacked myself! :B

Sounds like you need to find out who made the sending unit for your rig and then go from there. Centroid was fully aware of what model years of Monacos their sending units are on, so you could email them and ask if they made yours.

From what I have learned about the Centroid units there could be a few reasons for your issue. Maybe the sending unit is defective, not sending the right signal. Maybe the wrong sending unit was installed and it is not long enough for your tank. Maybe it is not properly calibrated. Centroid sending units can be calibrated for both empty and full readings.