Fuel gauge stops at 3/4

[Stephen Walsh]

2008 Monaco Cayman XL

the fuel gauge only goes to 3/4 when we fill up. We know we have 1/4 more than what the gauge is showing. We have to stop more often to fill up because when the gauge gets below 1/4, it shuts off the fuel to the generator even though we really have 1/2 tank!

Any ideas why? It sat for a couple years before we bought it. Needed a turbo right away with only 32,000 miles.

 

Edited July 31, 2022 by Stephen Walsh
Forgot to mention turbo was bad when we bought it at 32k and sitting for couple years might have had something to do with it.

[Dr4Film]

Your generator fuel supply line is not controlled by your fuel gauge. The generator will no longer work once the fuel in your tank gets to a level where the generator fuel pickup line can no longer reach the diesel fuel. That can vary significantly depending on how long the fuel line was installed at the factory by the person doing the task at the time.

Basically, it sounds like you need to recalibrate the fuel sender in your tank.

[Stephen Walsh]

2 minutes ago, Dr4Film said:

Your generator fuel supply line is not controlled by your fuel gauge. The generator will no longer work once the fuel in your tank gets to a level where the generator fuel pickup line can no longer reach the diesel fuel. That can vary significantly depending on how long the fuel line was installed at the factory by the person doing the task at the time.

Basically, it sounds like you need to recalibrate the fuel sender in your tank.

 

[Paul Busch]

I had the same problem with my sig. there is a sending unit on top my tank and I had to adjust it with a short Philips screwdriver past full and then back it off till correct according to my manual. Good luck.

[Cousin Eddie]

On my 03 Dynasty with a dual-fill full-width fuel tank I have noticed that if I fill from the “low” side of the coach that I can only get about 3/4 to 7/8 full but if I fill from the “high” side I’m able to completely fill the tank with the gauge showing full. Take note of which way the coach is leaning when stopped in the fuel lane and fill from the high side. (You may also have a sensor that needs to be recalibrated but this may help solve the problem). 

[Lenny D]

My fuel gauge will stop dropping at 1/2 a tank. I found out when my genny and my Aqua Hot both quit. The Aqua Hot one day, the genny the next. As Richard said, both Gen and AH are fed from the main tank with their fuel lines positioned at about 1/4 tank level. When I dropped below that they were denied fuel. In my defense, I didn't know that my gauge was not working properly. I think its something we forgot to go over when I purchased her or something we did go over and I forgot .. Since the rigg was sitting parked for a month and I was just running the genny and AH I figured 'Wow, the genny and the AH don't burn much fuel at all..lol" ... So, after reading these posts I'm going to look into re-calibrating the sensor. . . Or to be honest, I would rather fuel up at 1/2 a tank anyway. I have the Silverleaf system plugged into my diagnostic port and I can set up a miles driven vs fuel consumed readout and just keep it real from there. Fun Fun Fun ..  never knew how much fun it was to own a Class A DP .. Actually . I love it !!

Happy and safe motoring.

Lenny DePiano

2002 Monaco Windsor (Richards buyer)

[Frank McElroy]

On 7/31/2022 at 10:45 AM, Stephen Walsh said:

2008 Monaco Cayman XL

the fuel gauge only goes to 3/4 when we fill up. We know we have 1/4 more than what the gauge is showing. We have to stop more often to fill up because when the gauge gets below 1/4, it shuts off the fuel to the generator even though we really have 1/2 tank!

Any ideas why? It sat for a couple years before we bought it. Needed a turbo right away with only 32,000 miles.

 

Please post a picture of the top of your fuel sending unit.  Around about 2008, Monaco changed their fuel sending units.  On my coach, they went with a sending unit that had a circuit board inside.  These sending units are much different than the centroids used in earlier Monaco coaches.

On my 2008, the sending unit has a circuit board with about 20 reed switches activated by a magnetic float all internal to the round cylinder.  There is no calibration.  If you have this type of sending unit, one bad solder joint can cause a resistance error in the gauge readout.

[jacwjames]

On 7/31/2022 at 12:21 PM, Lenny D said:

My fuel gauge will stop dropping at 1/2 a tank. I found out when my genny and my Aqua Hot both quit. The Aqua Hot one day, the genny the next. As Richard said, both Gen and AH are fed from the main tank with their fuel lines positioned at about 1/4 tank level. When I dropped below that they were denied fuel. In my defense, I didn't know that my gauge was not working properly. I think its something we forgot to go over when I purchased her or something we did go over and I forgot .. Since the rigg was sitting parked for a month and I was just running the genny and AH I figured 'Wow, the genny and the AH don't burn much fuel at all..lol" ... So, after reading these posts I'm going to look into re-calibrating the sensor. . . Or to be honest, I would rather fuel up at 1/2 a tank anyway. I have the Silverleaf system plugged into my diagnostic port and I can set up a miles driven vs fuel consumed readout and just keep it real from there. Fun Fun Fun ..  never knew how much fun it was to own a Class A DP .. Actually . I love it !!

Happy and safe motoring.

Lenny DePiano

2002 Monaco Windsor (Richards buyer)

It's always good to know how much fuel the genny or your Aquahot use before they cut off.  I found out pretty quick as right after we bought the coach I decided to change my flooring and didn't have a power source so was running the generator quite a bit until it died.  Drove the rig to the fueling station and it took 100 gallons of my 128 gallon tank to fill it up. 

I also use my Silverleaf to monitor fuel consumption and plan my fillups on that.  Don't even look at the dash fuel gauge anymore.  My rig has the Centroid sending unit, I did try to do the adjustment that helped but not much.  My last trip when I knew I was below 1/2 tank my gauge was still reading 3/4 full.

 

FWIW, I've been communicating with Dr4Film ever since I bought my 2002 Windsor, he is a great resource for information and I know that he took great care of his coach.  You definitely got a winner. 

Edited August 2, 2022 by jacwjames

[Lenny D]

8 minutes ago, jacwjames said:

It's always good to know how much fuel the genny or your Aquahot use before they cut off.  I found out pretty quick as right after we bought the coach I decided to change my flooring and didn't have a power source so was running the generator quite a bit until it died.  Drove the rig to the fueling station and it took 100 gallons of my 128 gallon tank to fill it up. 

I also use my Silverleaf to monitor fuel consumption and plan my fillups on that.  Don't even look at the dash fuel gauge anymore.  My rig has the Centroid sending unit, I did try to do the adjustment that helped but not much.  My last trip when I knew I was below 1/2 tank my gauge was still reading 3/4 full.

 

FWIW, I've been communicating with Dr4Film ever since I bought my 2002 Windsor, he is a great resource for information and I know that he took great care of his coach.  You definitely got a winner. 

We had to have looked at over a dozen other coaches before we settled on Richards 2002 Windsor. . . Some of the other coaches had some pretty extensive interior upgrades and they were later models in the same price range .. .. But there was always something about the seller that turned me off. I'm gonna say this. I found Richards Windsor via a broker, Pop RV .. In all honesty, Pop did a decent job helping us find the coach but the reason I went for this Windsor was Richard. We still talk regularly and he continues to impress me with his knowledge and insight .. I fell we were very fortunate to find an seller who took such good care and pride in their coach. I agree. Definitely a winner.

[Guest Ray Davis]

9 hours ago, Frank McElroy said:

Please post a picture of the top of your fuel sending unit.  Around about 2008, Monaco changed their fuel sending units.  On my coach, they went with a sending unit that had a circuit board inside.  These sending units are much different than the centroids used in earlier Monaco coaches.

On my 2008, the sending unit has a circuit board with about 20 reed switches activated by a magnetic float all internal to the round cylinder.  There is no calibration.  If you have this type of sending unit, one bad solder joint can cause a resistance error in the gauge readout.

 

Thanks Frank, great info.  I like the idea of reed switches rather than the capacitance principle of my 03 Windsor gauge.  I never really feel like I can trust mine.

I have seen senders on Amazon with reed switches but as I recall they only have 5 switches, I was a little skeptacle if 5 was enough, 20 switches seem much better.

Do you know if a sender like yours will work in an older coach like mine?   I'm guessing I have 2 areas to consider,  will it fit the hole,  and will it function properly electrically with my dash gauge. 

My Trip Tek gives me tons of info including gals used but for fuel level I prefer to use my gauge,  I guess I'm old school.

[jacwjames]

35 minutes ago, Lenny D said:

We had to have looked at over a dozen other coaches before we settled on Richards 2002 Windsor. . . Some of the other coaches had some pretty extensive interior upgrades and they were later models in the same price range .. .. But there was always something about the seller that turned me off. I'm gonna say this. I found Richards Windsor via a broker, Pop RV .. In all honesty, Pop did a decent job helping us find the coach but the reason I went for this Windsor was Richard. We still talk regularly and he continues to impress me with his knowledge and insight .. I fell we were very fortunate to find an seller who took such good care and pride in their coach. I agree. Definitely a winner.

JFYI

Back in 2010, while Monaco was in bankruptcy, they let the security on their dealer website lapse.  Someone posted a link to the site that allowed you to go in and search for parts using the coach number.  There were hundreds of parts pages available and I spent several days reviewing and downloading ones I thought might be useful.  Wish I could have got them all but I had to do one at a time so it took a while but I got about 100 parts pages in my files.  Some are very useful as they have the Monaco part number which you can usually still use on the https://revrvparts.com/rev-recreation-group  But in most cases it has the vendor parts number. 

I have also accumulated a lot of other information for my coach so if your looking for something let me know, I may have it.

[Frank McElroy]

29 minutes ago, Ray Davis said:

Thanks Frank, great info.  I like the idea of reed switches rather than the capacitance principle of my 03 Windsor gauge.  I never really feel like I can trust mine.

I have seen senders on Amazon with reed switches but as I recall they only have 5 switches, I was a little skeptacle if 5 was enough, 20 switches seem much better.

Do you know if a sender like yours will work in an older coach like mine?   I'm guessing I have 2 areas to consider,  will it fit the hole,  and will it function properly electrically with my dash gauge. 

My Trip Tek gives me tons of info including gals used but for fuel level I prefer to use my gauge,  I guess I'm old school.

The manufacturer of my fuel sending unit is ISSPRO.  https://isspro.com/page_Level_Fuel_Senders.php

Because of the larger diameter tube, you can't tilt it to remove from the tank like you can with the Centroid units.  So, what I did was to remove the top cap and slide out the circuit board from the metal tube housing.  I used a spring clamp to keep the metal housing from falling into the fuel tank.  The bolt pattern is pretty common for a fuel sending unit.  As for compatibility with the fuel gauge, if the resistance matches what you have there is a good possibility that it would work.  Customer service as ISSPRO should be able to help if you can tell them the resistance range of your existing sending unit.

If you look closely, one end of the circuit strip has the reed switches closer together.  This is the area from E to about 1/3 full.  So in that range you have the highest gauge resolution of fuel level in the tank.  The picture below gives you an idea of how long the sending unit is.  In my case, empty leaves about 40 gallons of fuel still left in the tank.

[Guest Ray Davis]

Yeah,  I was afraid it wouldn't fit physically.   Here is a picture of one on Amazon which looks like it might tilt sufficently to go in.  I haven't decided if I want to try one or not.  Resolution is still a concern.   My Centroid just seems to become random in it's reading.   It sort of lies to me.  LOL   I would prefer it would stop all together then I  would know my gauge is not working.  

[Lenny D]

1 hour ago, jacwjames said:

JFYI

Back in 2010, while Monaco was in bankruptcy, they let the security on their dealer website lapse.  Someone posted a link to the site that allowed you to go in and search for parts using the coach number.  There were hundreds of parts pages available and I spent several days reviewing and downloading ones I thought might be useful.  Wish I could have got them all but I had to do one at a time so it took a while but I got about 100 parts pages in my files.  Some are very useful as they have the Monaco part number which you can usually still use on the https://revrvparts.com/rev-recreation-group  But in most cases it has the vendor parts number. 

I have also accumulated a lot of other information for my coach so if your looking for something let me know, I may have it.

 

2 hours ago, jacwjames said:

It's always good to know how much fuel the genny or your Aquahot use before they cut off.  I found out pretty quick as right after we bought the coach I decided to change my flooring and didn't have a power source so was running the generator quite a bit until it died.  Drove the rig to the fueling station and it took 100 gallons of my 128 gallon tank to fill it up. 

I also use my Silverleaf to monitor fuel consumption and plan my fillups on that.  Don't even look at the dash fuel gauge anymore.  My rig has the Centroid sending unit, I did try to do the adjustment that helped but not much.  My last trip when I knew I was below 1/2 tank my gauge was still reading 3/4 full.

 

FWIW, I've been communicating with Dr4Film ever since I bought my 2002 Windsor, he is a great resource for information and I know that he took great care of his coach.  You definitely got a winner. 

 

1 hour ago, jacwjames said:

JFYI

Back in 2010, while Monaco was in bankruptcy, they let the security on their dealer website lapse.  Someone posted a link to the site that allowed you to go in and search for parts using the coach number.  There were hundreds of parts pages available and I spent several days reviewing and downloading ones I thought might be useful.  Wish I could have got them all but I had to do one at a time so it took a while but I got about 100 parts pages in my files.  Some are very useful as they have the Monaco part number which you can usually still use on the https://revrvparts.com/rev-recreation-group  But in most cases it has the vendor parts number. 

I have also accumulated a lot of other information for my coach so if your looking for something let me know, I may have it.

Thank you. Actually what I'm currently looking for is a new sending unit for the cruise control and a new emblem for the outside entrance and the rear cap. Mine are faded out. The cruise control wasn't working when I purchased her. Richard told me what and where the issue was. I'll need to reach out to him for more info. . Thank you very much.