Suzuki MFD gauges with older engines (2006)

[gofishin]

Not the first time I have heard of counter rotator's using a bit more fuel. Don't know the reason why but it could explain the variation. Fuel burn via the engines ECU's isn't "metered" as such as far as I know. It's estimated off typical injection volume and RPM which for a given powerhead would be the same - regardless of what is actually happening. I'm not sure if throttle position is somehow factored in but if it isn't - that could be the variation - ie - more fuel to achieve the same RPM.

scottar I was under the impression that for some time now with EFI the fuel is precisely delivered, with many sensors monitoring all sorts things, to help meter the exact amount of fuel... but ... maybe not, as it then should only be simple math for the ECU to do a time-based summation of L/h to get L


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[seastrength]

Not sure of your TG engine model but assume it’s not the AP (fbw) model Seastrength? Was the engine harness changed as well, or just the gauge?


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Hi gofishin. The 2015 TG model is setup for slow speed trolling. I assume TG stands for trolling guide or something similar. I am not sure what AP means, pardon my ignorance on technical matters. The TG unit allows for 50rpm changes to boat speed under 1200rpm. I have kept fuel usage records since the MFG upgrade last year to show an 8-9% underestimation of fuel flow. Prior to the new MFG gauge, the engine harness was changed three times with the old round gauge to correct NMEA data error. I understand that the TG model was not compatible with the older gauge. The new square MFG gauge has internal software with no need for the calibrated harness? At least that is what I am told. There are several technical gurus on the site who can probably better explain the finer detail. My plan is to have the fuel system software recalibrated when the next service in due in August. SS

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[seastrength]

Hi gofishin. The 2015 TG model is setup for slow speed trolling. I assume TG stands for trolling guide or something similar. I am not sure what AP means, pardon my ignorance on technical matters. The TG unit allows for 50rpm changes to boat speed under 1200rpm. I have kept fuel usage records since the MFG upgrade last year to show an 8-9% underestimation of fuel flow. Prior to the new MFG gauge, the engine harness was changed three times with the old round gauge to correct NMEA data error. I understand that the TG model was not compatible with the older gauge. The new square MFG gauge has internal software with no need for the calibrated harness? At least that is what I am told. There are several technical gurus on the site who can probably better explain the finer detail. My plan is to have the fuel system software recalibrated when the next service in due in August. SS

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TG model is fly by wire.

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[gofishin]

TG model is fly by wire.

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Ahhh, ok. They must have replaced the previous ‘Troll Mode’ (separate/dedicated rocker switch to control the troll speed) and is now in the gauges.

Why I asked about the harness, was that ‘from what I understand’ with the old gauges (pre SMG4), the interface was part of the harness, but in the SMG4 it is in the gauge. Hence if you had old harness + new gauge, the two interface firmware could be confusing the data.

Grant (Moonlighter) is this correct?

As far as I am told, there is no calibration possible for the new gauges, even buy a Zuke tech with a flux capacitor PC ☹️

PS. Sorry for hijacking your post james1!


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[seastrength]

Ahhh, ok. They must have replaced the previous ‘Troll Mode’ (separate/dedicated rocker switch to control the troll speed) and is now in the gauges.

Why I asked about the harness, was that ‘from what I understand’ with the old gauges (pre SMG4), the interface was part of the harness, but in the SMG4 it is in the gauge. Hence if you had old harness + new gauge, the two interface firmware could be confusing the data.

Grant (Moonlighter) is this correct?

As far as I am told, there is no calibration possible for the new gauges, even buy a Zuke tech with a flux capacitor PC

PS. Sorry for hijacking your post james1!


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Thanks for that explanation gofishin. Your information is in agreement with what I have been told by the Suzuki technician, except for the MFG gauge recalibration. They may have feedback errors to Suzuki Japan for advice? Cheers SS.

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[scottar]

scottar I was under the impression that for some time now with EFI the fuel is precisely delivered, with many sensors monitoring all sorts things, to help meter the exact amount of fuel... but ... maybe not, as it then should only be simple math for the ECU to do a time-based summation of L/h to get L


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Probably but that's also the problem - the fuel burn is done by math - not by measurement. The system knows what "should" be happening by the sensors - intake temps, throttle positioning, rpm and so on and works out the amount of fuel to inject which is then estimated by injector opening times and rail pressures (that's my extremely basic understanding from discussions with a Caterpillar tech) . It doesn't know what is actually happening - it's not actually measuring the amount it does put in.

[Moonlighter]

Not the first time I have heard of counter rotator's using a bit more fuel. Don't know the reason why but it could explain the variation. Fuel burn via the engines ECU's isn't "metered" as such as far as I know. It's estimated off typical injection volume and RPM which for a given powerhead would be the same - regardless of what is actually happening. I'm not sure if throttle position is somehow factored in but if it isn't - that could be the variation - ie - more fuel to achieve the same RPM.

Its far more sophisticated than that Scottar - its not based on a “typical” Injection volume. It is based on actual fuel injected. The ecu takes into account input from every engine sensor including throttle position, which then determines how much fuel it injects.

The resulting data is transmitted to either the SMG4 gauge or to the Interface cable, depending on which system you have, and I think the accuracy problem then occurs in the software in the SMG4 gauge and how it uses the actual data from the engine to then calculate and display fuel flow and fuel used results.

In the “old” Suzuki system that uses the interface cable, there was the ability to calibrate the fuel data to eliminate any inaccuracy that was found in the fuel data. Whereas the SMG4 gauge, which effectively does the functions that the interface cable used to do, doesnt have that capability. Why? You would have to ask the Japanese engineers who designed it.

In respect of the current generation of counter rotating engines and fuel economy, as Gofishin said, most likely the first place to look to explain variation would be the propellors - its becoming more well known that no 2 props are the same even when made by the same company and same model and size.

Every tiny variation in any prop manufacture, whether that be blade surface area, thickness, diameter, pitch, cup ...... will end up having a measureable impact on prop performance and therefore on fuel use. Add in the need to have one LH and one RH prop and making mirror reverse props identical gets harder again.

I do know one Suzuki dealer who insists on having both props computer scanned and tuned to as close to identical as is possible whenever he fits twin engines - because it eliminates stuff that annoys people, like resonance and vibrations. I dare say that fuel economy would be a side effect benefit of doing that as well.

[scottar]

Its far more sophisticated than that Scottar - its not based on a “typical” Injection volume. It is based on actual fuel injected. The ecu takes into account input from every engine sensor including throttle position, which then determines how much fuel it injects.

The resulting data is transmitted to either the SMG4 gauge or to the Interface cable, depending on which system you have, and I think the accuracy problem then occurs in the software in the SMG4 gauge and how it uses the actual data from the engine to then calculate and display fuel flow and fuel used results.

In the “old” Suzuki system that uses the interface cable, there was the ability to calibrate the fuel data to eliminate any inaccuracy that was found in the fuel data. Whereas the SMG4 gauge, which effectively does the functions that the interface cable used to do, doesnt have that capability. Why? You would have to ask the Japanese engineers who designed it.

In respect of the current generation of counter rotating engines and fuel economy, as Gofishin said, most likely the first place to look to explain variation would be the propellors - its becoming more well known that no 2 props are the same even when made by the same company and same model and size.

Every tiny variation in any prop manufacture, whether that be blade surface area, thickness, diameter, pitch, cup ...... will end up having a measureable impact on prop performance and therefore on fuel use. Add in the need to have one LH and one RH prop and making mirror reverse props identical gets harder again.

I do know one Suzuki dealer who insists on having both props computer scanned and tuned to as close to identical as is possible whenever he fits twin engines - because it eliminates stuff that annoys people, like resonance and vibrations. I dare say that fuel economy would be a side effect benefit of doing that as well.

Propellers and the like will certainly have an impact on efficiency but shouldn't create an error in fuel management as it's all "downstream" of where that happens. I've run quite a few different props on my E-Tec - none of which created an error in fuel management but they did have vast differences in the economy. If the fuel management software isn't reading accurately in enough cases, it stands to reason that they are using a value somewhere in their calculation that is off. I can't imagine why running a counter rotator would be a cause - once again it's all downstream and shouldn't have an effect if indeed they are "measuring" the fuel - but it seems the addition of the counter rotating motor is the common denominator in fuel management issues. Either that or they have an issue with their math adding the two together.

[Dignity]

Propellers and the like will certainly have an impact on efficiency but shouldn't create an error in fuel management as it's all "downstream" of where that happens. I've run quite a few different props on my E-Tec - none of which created an error in fuel management but they did have vast differences in the economy. If the fuel management software isn't reading accurately in enough cases, it stands to reason that they are using a value somewhere in their calculation that is off. I can't imagine why running a counter rotator would be a cause - once again it's all downstream and shouldn't have an effect if indeed they are "measuring" the fuel - but it seems the addition of the counter rotating motor is the common denominator in fuel management issues. Either that or they have an issue with their math adding the two together.

And it is always the port motor that uses more fuel, mind you my sample rate is not big as I only know of 3 people who have bothered to keep track and it seems to be around the 5% variation, for example twin 600 litre tanks, the port tank will take more fuel every time.

[james1]

Yep, my port motor uses about 10% more that starboard. Consistently. I run a flowscan system that is accurate to within a litre over 400litres.

[gofishin]

Yep, my port motor uses about 10% more that starboard. Consistently. I run a flowscan system that is accurate to within a litre over 400litres.

James good to know re accuracy. I looked at a few fuel monitoring systems, think Floscan was one. Another was Maretron. There was one that seemed good, but then found some gripes on various forums, none of which showed them any praise. Can’t remember the dud brand, but good to hear re Floscan.

In the end I canned the extra expense, hoping Suzuki would eventually work out a fix. I mean, it’s 2020, surely it can’t be that hard!

PS. I guess that also means you don’t get any engine info via NMEA 2k. That’s a bummer. First calibration my STB used a lot more than PT, which is contrary to info I now have available (but have also changed props).

However since setting up my engine data on MFD, I can see revs and fuel flow to much higher accuracy. Hence I set my revs differently to get the same L/h to within a few tenths. Since then have used same both sides in last calibration check.

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[gofishin]

Thanks for that explanation gofishin. Your information is in agreement with what I have been told by the Suzuki technician, except for the MFG gauge recalibration. They may have feedback errors to Suzuki Japan for advice? Cheers SS.

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SS, fyi heard from my Zuke mechanic today that he had a single install with calibration/fuel use errors. He fixed it by replacing the gauge, and the client is saying his consumption is now spot-on.


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[seastrength]

SS, fyi heard from my Zuke mechanic today that he had a single install with calibration/fuel use errors. He fixed it by replacing the gauge, and the client is saying his consumption is now spot-on.


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Thanks for that info gofishin. I was planning to get the gauge recalibrated at the annual service in August. Will be interesting to hear Suzuki's response as the motor will be out of warranty by then. Cheers SS

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[scottar]

Interesting. Is the gauge software updateable or do they replace to update - anyone know?

[gofishin]

Interesting. Is the gauge software updateable or do they replace to update - anyone know?

Oops, pressing buttons with no reading glasses... got the right one (Quote) in the end .

The Interface is within each gauge, and the firmware can’t be updated or reflashed etc I am told, so replace the gauge is the answer Scott.


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