New Prostar - Fuel Gauge Issue

[Eljaybee]

I have a 2014 Prostar and there seems to be no consistency to the fuel gauge easing. It seems like the fuel gauge reads 3/4 one minute 1/4 the next and back up to 1/2 the next. Anyone w a new model Prostar experience similar issues? Any help is appreciated.

[Horton]

see old thread...

https://www.ballofspray.com/forum#/discussion/18004/gas-gauge-on-new-prostars/p1

[LoopSki]

welcome to the club!

[Eljaybee]

Thank you Horton. Appreciate it

[epnault]

The biggest thing to remember is that this gauge doesn't like topping off the fuel. What my dealer explained to me is not to refuel until less that 1/2 tank and when you refuel make sure you fill the tank and while doing this make sure the master power switch is off so it resets after refueled.

[Horton]

Starting with the 2018 boat there's an option to use the fuel management system as opposed to the sensor inside the tank. It's a little confusing the first couple times you use it because you have to tell the boat if you've added gas every time you turn it on but it never fails. The system calculates fuel consumption and subtracts that from how much fuel you say you have put in. The whole conundrum of wondering if your fuel gauge is accurate is completely eliminated.

[BraceMaker]

I've not once trusted a fuel sender in a boat, wouldn't trust the fuel management system either.

 

I either lift the seat and look at the tank, or keep a rod on the dock to dip into my tank to check the level. I prefer the rod but new boats don't always have the tank right there.

[Roger]

@Eljaybee - Mine was one of the problem boats that got a new sensor. My gauge has been perfect since then (> 2 years).

[Horton]

@BraceMaker why would you not trust the fuel management system? You do have to enter the gallons when you fuel the boat but if you can do that it works awesome. Every once in a while I really really fill the tank all the way and then set the system to "Full" to make sure I have not goofed something but it has never failed me.

[BraceMaker]

@Horton I have brothers, some are very bad at fuel management. They use my boat.

 

 

[Rednucleus]

Us old guys carry a 2 gallon can for when the gauge lies!

[LoopSki]

@BraceMaker the dip stick or visual check will not work on a ProStar. wish mine had the fuel manager

[Horton]

@BraceMaker bonehead brothers is not a boat design flaw.

 

What year is your boat? You can't use a dipstick or a visual on new boats

[ScottScott]

The problem with the system is that it only calibrates the gas capacitance when its filled up full. So if you put gas in, but don't fill up, that gas may have a different ethanol content and not get calibrated. Ours has gotten out of sync before when we did a partial fill up, and it took a full fill up to get it to re-calibrate and everything worked fine after. For us trailering, its easy to fill up each time we head out. For people on a private lake or ski schools, filling up with 5 gallon cans, you may never see it full. For probably the majority of the people that own these boats, this probably isn't the best fuel gauge system. This fuel management system I guess is an answer to this, but is an unsatisfactory answer. Even tho it doesn't negatively effect us often, I would say this is maybe the one thing that Mastercraft did wrong on this boat.

[lakeho26]

@Horton, can you explain a bit on where to find the fuel management system? I have an 18 and have not seen in the manual or on any of the screens an option for this. Do you need a dealer code?

[Horton]

@lakeho26 It might not have been an option on all of the 2018s. My First one did not and my second 2018 did. My 2019 does.

 

@ScottScott Honestly I have used boats of all brands over the years and gas gauges are notoriously unreliable. The fuel management system seems odd if you do not use it all the time but it works great. I do not understand why anyone would not use it.

[skimtb]

Do you have to 100% fill boat to initiate the system?

How.

Would that be at station using pump until shutoff or w 5 gallon cans until it comes out the vent?

[BraceMaker]

@Horton its not but a 94 prostar has a nice straight shot down into the tank.

 

Works for me. And of course that's no excuse - I'll be the first to sign up for removable fuel tanks in a ski boat.

[Golfguy]

In the fuel management system there is the opton of either telling it you filled the tank, or telling it how much gas you added. On my 2019 when I fill the tank and say the fuel tank says I put in 15 gallons the fuel management system concurs with that every time.

[Horton]

@BraceMaker 94 is a cool boat but NOT what this thread is about. I should give myself a panda for not realizing it sooner.

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

[ScottScott]

@skimtb Fuel level needs to touch at least within 2" of the top of the probe, then it will recalibrate.

[BraceMaker]

@Horton I straight up said I use a dipstick.

 

#1994-2014 when the $ works out.... the. Again I'm kinda a 10K ski boat tiger. 3rd times the charm.

[ROBOT]

@Horton

 

http://media.tumblr.com/fe497dd337d9af8479bb6398b9565d16/tumblr_inline_mg6n5ltl6X1rxe4lt.gif

 

 

 

[BraceMaker]

Is a robot panda a good thing???

[Cnewbert]

@Horton According to the Owner’s Manual the ‘20 Prostar has a fuel capacity of 25 gallons. I just filled our boat at the pump and input “Full” then “Save” on the fuel management screen. The fuel management screen now says I have 22 gallons of fuel and it is 100% full. Where are the other 3 gallons? How could a 25 gallon tank be 100% full with just 22 gallons? That’s only

88% full by my math. Any insights you or anyone else can offer will be appreciated. Thanks.

 

 

[skimtb]

@Cnewbert No clue if this applies but my ‘94 had the fuel pickup (in the tank) a bit up from bottom of the tank. Like 5 gallons up... I was told this was so you didn’t pick up the “sludge” (overstatement) off the bottom.

How did you know it was “full”? Pump shutoff?

[dvskier]

22 gallons usable fuel perhaps?

[mmskiboat]

Thinking to start using this feature on our '20, but we are on a lake with no marina so have to jerry can, as others have said I cannot easily fill the tank to full without risk of a spill. Not sure what the steps would be start.

 

 

 

 

 

 

[Cnewbert]

@skimtb yes, the auto pump shut off. Clicked it a couple of times to be sure it was topped off. However, the fuel management system, as I understand it, does not measure actual gas added or fuel tank level. It relies on operator input for the amount of fuel added and adds that to the prior amount For the new total. During operation it measures fuel flow and continuously subtracts that amount from the starting total as you go. My input was “Full” and the system defaulted to 22 gallons. I think you and @dvskier are right... 22 gallons probably represents the useable number of gallons. 3 gallons is probably the amount below the in-tank fuel pick up line. If I find out anything different I’ll be sure to post it. @mmskiboat i think you could carefully fill your boat once from the jerry cans without spilling. Then input Full and Save on the fuel management screen. From that point on make a note of exactly how much gas you’ve put in each jerry can — or if you habitually add two cans, approx 10 gallons at a time, make a note of precisely how much gas you used to fill both cans at the station... maybe 10.4 gallons or whatever. Then completely empty the can or cans into the boat and input that exact number that you filled the can or cans. I think you would be good to go. All you need is that one time Full input as your starting point and maintain accurate inputs from then on.

[skimtb]

@mmskiboat Worry about it next year. Unless you think you are way off. 5 gal is approx 1/4 tank. Go ski.

[PeteTag]

Just bought a 2020 Prostar and having these same issues. Had my dealer turn of the Fuel Management System before I realized I had this issue. Anyone know how to turn it back on?

 

[mmskiboat]

@Cnewbert @skimtb Thanks for the input and I think I will just wait till I pull the boat to a station for fill up so probably will be next year.

 

@PeteTag Not at boat and it is undercover at the moment but it is under the menu preferences. Just have a look around and you will find it.

[jpwhit]

Other than using it on my Mastercraft and watching how it behaves, I don't have any inside info on exactly how Mastercraft implements their fuel management algorithms. I do have experience with how automobile companies implement it and suspect there are similarities.

 

In the automotive world, the algorithms are much more sophisticated than what folks describe here. I suspect this is also the case for the Mastercraft implementation. Typically, the algorithm does rely on data from the in-tank fuel sender as well info related to how much gas has been added.

 

In automobiles, it's very rare to prompt the user asking how much fuel was added. That's because people typically completely fill their cars pretty often. Therefore there is no need to ask the end customer if they added fuel. The computer simply watches the in-tank fuel sender and when it goes from something below full to something very close to full, the computer notices that event and decides that the tank was filled. This lets the computer automatically re-calibrate the fuel quantity based on knowing the capacity of the tank. This is how modern cars show data like "distance to empty" fairly accurately. If you think they are doing that from the in-tank fuel sender, that is not the case. The sender simply isn't accurate enough.

 

And if you're curious how the engine ECM calculated fuel usage, that is pretty easy and accurate on a fuel injected engine. It's derived by summing injector open times along with estimations of the injector flow rates from the algorithms and injector maps that keep the fuel/air ratio accurate.

 

In a boat, where there are certainly use cases where the user often doesn't fill the boat regularly, I suspect they felt the need to ask the user how much fuel was added. But like in automobiles, I suspect the computer still does pay attention to the fuel sender input. It just doesn't use that input alone to decide what to display on the fuel gauge. But I bet it does use that input to help keep the system somewhat calibrated. The advantage the computer has in watching that fuel sender input, is that it can watch it all the time, keep a history of the values, and apply analysis to that data. We all know that the fuel sender data jumps around a lot based on motion of the boat. As a user that only glances at the gauge now and then, it can be difficult to interpret that data accurately. Using computer-based fuel management, the computer can do a good job of interpreting the fuel sender input, the computer's internal tally of how many gallons it thinks is in the tank based on user input or detecting a fill-up, as well as the fuel usage reported by the engine ECM. Then it can display a much more consistent and fairly accurate fuel level.

 

If someone is really dying to know how sophisticated the Mastercraft algorithm is then I think it's possible to figure it out through experimentation. Just bring a small gas can along and tell the computer bad data about how much gas you added over a period of time. If I'm right, it'll handle that scenario better than you may think. If I'm not, then oh well now you know.

 

Personally, I'm pretty much on the same page as Horton. I tell it how much fuel I added, and it just seems to work pretty well. Therefore, I don't worry about fuel level and I just focus on skiing....

 

[Cnewbert]

@jpwhit very interesting stuff. Thanks. So based on your speculation about the coordination between the fuel management system and the in-tank sender, do you suggest that if the fuel management calculated I had, say, 6 gallons of fuel remaining, and I then added 10 gallons but didn’t input that data and just hit cancel when asked if I added fuel, that the fuel manager, using input from the in-tank fuel sender, would adjust the remaining fuel upward to something toward 16 gallons? That would certainly be easy enough to check. Since I always trailer my boat, next time I add fuel at about 6 gallons or so, I’ll add roughly 10 gallons from the pump but won’t input that amount. Then if the fuel manager remains at the original amount, even while the analog gauge climbs past 1/2 full, then it would appear the manager gets no input from the sender. But if the manager now displays a higher value than prior to adding gas, then there must be some level of communication between the two. Do I have this right?

[skibug]

It is TOTAL BULLSH*!$%!!T!!!!!!!!!! that an $80K boat not have a fuel gauge that works! I have a 2015 Prostar. We had the fuel sending unit replaced twice under warranty....still the same issue. Ran out of gas in the middle of the lake 2 weeks ago and the gauge was reading 3/8 of a tank. We are diligent in fueling at the end of every day. We knew the gauge was off because it would go from 1/2 to pegged on full with only adding 5 gallons, and we tried to manage it so we wouldn't overflow. Then, I said F%$#ck it!!! I am going to fill it until it overflows. This "seems" to have somewhat reset the sending unit, but for how long???? Again, total BS!!! And, you can't see through the tank to get any type of visual on level.

 

A burnt up fuel pump will set you back about $1000 or so at the dealer. Not good Mastercraft!!!!!!

 

I suggest making the tank less opaque and get rid of the gas gauge all together (save the time and money), it would be more effective and accurate.

 

Fuel Management system is just a poor, redundant band-aide of an excuse for the real problem and another thing adding variability to the root cause. And, another thing to go wrong!!

[ScottScott]

@skibug I agree 100%. As much as I love our Prostar, and am a Mastercraft fan. The fuel gauge is an abysmal failure, and the fuel management is a ridiculous work around (which I don't have, and not sure if a firmware update will give us.) I understand the '21 has fixed the issue? I'm curious as to how, and whether that can be retrofitted to older models. (If so then Mastercraft should do that for all '14-'20 boats at no cost.) The fuel sender design is no good for a boat in general, but especially a ski boat that is most often filled with 5 gallon cans, and is impractical to fill to full each time.

 

[jpwhit]

@Cnewbert that pretty close. But with fuel management turned on the physical gauge on the dash no longer shows simply what the in-tank fuel sender is reporting. On all the newer boats, all the "manual" gauges are 100% controlled by the computer. With fuel management turned off, the computer simply reads the signal from the fuel tank sensor and tell the gauge to display that info in raw form. With fuel management turned on, the computer tell the gauge what to show based on the algorithms I described above.

 

So with the experiment you describe, I wouldn't expect the gauge to change much immediately after adding fuel. The part that would be interesting, is what does the gauge show after that as you use up the fuel in the tank. If it simply goes down as the computer thinks you've used up 6 gallons and shows empty when there are really 10 gallons left, then I'm wrong and the algorithm is very simple and not that similar to what is implemented in most modern cars.

 

If the algorithm is more sophisticated, then what I expect may happen, is it won't go down much as you use the 6 gallons and may actually go up some as the computer analyzes all the input data it collects over time. But in the end, it may show empty in the ballpark of when you've used up 16 gallons total.

[PeteTag]

So I'm new to this forum. Anyone ever hear an official statement from MC on this? Love my 2020 Prostar, but agree this is total bullshit. Sold my old MC with gas guage issues, and never dreamed I'd have them in a brand new boat!

[Cnewbert]

@PeteTag personally I’m not saying I have any issues at all with my system. Just an incomplete understanding of how it works. If anything is total bullshit it’s the pathetic owner’s manual MC provides to people spending 10s of thousands for their otherwise great boats. For this somewhat confusing subject of the fuel management system, it’s theory and practical use, I can find absolutely zero mention of it anywhere in the manual. Though the manual is so cluttered with irrelevant information on completely different MC models, perhaps I’ve overlooked it. In the Prostar section I can, however, find information on the 2nd ballast tank or the trim tab settings and position — neither of which is even available on the Prostar. (Someone should lose their job.)

 

On a positive note, I will say that since I filled my tank for the first time and entered Full and Save on the fuel management system screen, my fuel manager and the analog gauge have been perfectly matched.

[Cnewbert]

Just a follow up to my post almost 2 weeks ago: my Fuel Management System and my analog gauge continue to be effectively in precise agreement with each other on remaining fuel ever since I topped the tank off a while back at 22 gallons. And after careful monitoring it does appear as though the two might communicate with each other as @jpwhit suggested. I only say that because there is a very slight difference in the % of remaining fuel displayed in the FMS and the purely mathematical result one would get by dividing the total gallons shown in the FMS by a full tank of 22 gallons. But that percentage is virtually identical to what the analog gauge shows (i.e. 7/16 remaining = 44% of a full tank while the FMS might show the same 44% and 9.5 gallons remaining, though 9.5 gallons would actually be 43% if it relied solely on a straight mathematical result).

 

Anyhow, however it actually works, it’s proving thus far to be, hands down, the most accurate fuel gauging system I’ve ever had on a boat. Mind you, we only have 45 hours on our new Prostar, so the durability of the system is yet untested. But for the time being, I love it.

[Dacon62]

Have said it before. Gauge sucks. Should be redesigned to work properly. You can buy a POS car that has better gauge accuracy.

It needs to be fixed. Everything else I love about my 17.

[Laz]

Hi all. 2023 Mastercraft here with < 30 hours.  Fuel gauge said 35% yesterday morning which I think was somewhat accurate.  Now keeps hovering around 95% to 100% with no fuel added.  I have not been using the fuel management system.

Any suggestions?  I usually fill with jerry cans so it’s not usually completely full.

[dave2ball]

@Laz this is known issue for  prostars. Try filling it full and see if it resets the fuel gauge. 

Edited June 18, 2023 by dave2ball

[Broussard]

A representative from Centroid (MasterCraft's supplier for electronic fuel senders) has suggested that the boat be filled completely (with the key off) in order to help calibrate the unit. Additionally using a consistent grade of fuel with consistent level of ethanol (or lack thereof) will result in a more accurate reading.

[Horton]

personally, I have preferred to use the fuel management system. it does require a few extra touch screen presses every time you fire up the boat but as far as knowing what if you will level is it is foolproof.

[skihacker]

I suspect the fuel management system wouldn't work for our boat? We're not on a private pond, courses aren't right off our dock. Especially in fl lots of travel to get to the ski sites. It actually hasn't been that bad to recalibrate the gauge once in a while even if it's annoying. Run the tank down pretty low then usually take around 20 gallons to fill with switch off, the last 5 gallons I pour slowly out of smaller cans till fuel is visible in the lower part of the fill tube. 

[lpskier]

We can build a boat that knows how fast it is going within 1/100 th mph and knows within 2 cm of where it is in the course, but engineers still can’t build a fuel gage for a ski boat that is worth a damn. 

[JackQ]

I have to call BS on” using a consistent grade of fuel with consistent level of ethanol (or lack thereof) will result in a more accurate reading.” The grad of fuel about of ethanol should have no effect on a “fuel level reading” it should be accurate if you put water or motor oil, it does not measure density. 

[Horton]

@skihacker no reason why I fuel management wouldn't work in that situation or I don't understand why not. when you put 20 gallons in you tell the computer you put 20 gallons in. it's not brain surgery. 

you shou

[Broussard]

@JackQ 

Quote

"This is Joel, an engineer at Centroid Products. We make fuel senders for MasterCraft. I'll give some background info and them hopefully do some science with y'all to figure out what's up.

We make fuel senders that measure capacitance between their two concentric tubes. The more fuel there is between the tubes, as opposed to air, the more capacitance and the higher the reading. There's a microcontroller in the sender's head to convert the capacitance into a Send voltage for the gauge. The selling point is no moving parts in the sender. Plus the microcontroller lets us do averaging of the output to smooth out chop, and MC has us doing 12 seconds of averaging.

Ethanol in gasoline complicates things for measuring capacitance, though. Gasoline with 10% ethanol has twice the capacitance of gasoline without ethanol, and the percent can be anywhere between 0-10%. To correct for this there is a Full Detection stinger in the top couple inches of the sender to detect when the sender has been powered up with a newly filled tank and correct the Full cal if needed."