SMIS CheckSum error and settings reset

[Mawrob]

I recently installed the Suzuki Engine Interface and a 4" SMIS gauge on my twin 2005 DF250s. The primary application is for fuel consumption. Apart from the initial calibration being way off the system works fine about 75% of the time. About 25% of the time I get the following CheckSum Error message and all my settings are reset forcing me to redefine # of engines, # tanks, fuel source etc all over again.

SMIS checksum error.JPG

As you can imagine it is very frustrating.

The issue only occurs intermittently on starting the motors (which powers the network) or powering the NMEA 2000 network with the motors off. The latter auxiliary powering scenario appears to eliminate the problem being a power dip issue messing with the electronics. I power my NMEA 2000 network using the Suzuki quad power node that performs an "OR" on three power sources with auxiliary taking priority. My batteries are in good shape, the voltage at the dash appears solid, and all the rest of my electronics is working fine.

The following is a diagram of my setup.

Suzuke Engine interface network.jpg

I Googled a similar issue here with no resolution: I-Command checksum error - Owners Message Board

Can anyone help me troubleshoot this? (I am an electronic engineer so please do not worry about being too technical with your suggestions).

Thanks for your help.

[Harper]

I had the same problem with my SMIS gauge (on a single DF150) for the first week or so, then it mysteriously went away. I have no idea why it was doing it, but as is suggested in the post on the link you provided, I would also guess it has something to do with power at startup. Mine was installed also primarily for fuel management, and like yours was way out of calibration. I've calibrated three times so far, and each time it gets closer, but is still nowhere near being right on that. One would think that Lowrance could do better with this gauge, since it obviously doesn't just happen on Suzuki engines. That gauge on the link you showed, for an Evinrude E-tec is obviously the same gauge that Lowrance makes for Suzuki.

I'm just hoping my checksum problem doesn't come back. I'm no electronic engineer, but the only thing I can suggest you try is to move the power node connection to the "T" between the gauge and your Raymarine E120.

[Mawrob]

Thanks for your suggestion Mike. I am in contact with the dealer I purchased the system from. They have contacted Suzuki who suggest trying a hard reset and starting over. I think this will blow away my hard earned calibration so I have asked if there is a way to get the SMIS to read accurately without having to recalibrate multiple times. The calibration issue is perhaps due to the firmware not matching the flow sensor. My engines had the ECUs replaced as part of a recall so maybe the year does not match the way the ECU calculates the flow rate. I read they changed the calculation after a certain year.

Not sure at this point but please keep the suggestions flowing.

[Harper]

Mawrob, did you get your gauge from Brownspoint? That's where I got mine this spring. The fuel flow was originally 3.9 gal/hr at idle and 40+ gal/hr at cruise. Off by a factor of around ten, I figure. After three calibrations, it's at 1.2 gal/hr at idle, and that's still way high. Due to circumstances, I've not been able to get on the water since May, and won't again until mid-October. So it's frustrating, and I'm not even sure it will eventually read correctly. I'm thinking that maybe next time I calibrate, if it says I've used ten gallons and I refill with five, I might just enter that I refilled with two or three.

But I ask about Brownspoint Marine, because when I queried them in mid-May about having heard of this calibration issue before, they indicated that they had not.

[Harper]

Mawrob, I've been perusing the internet and found a long discussion (17 pages) on The Hull Truth forum, much of which deals with fuel calibration on the Suzuki gauge, or the Lowrance LMF400, which is the same gauge. The original poster and most informed guy is also a member of this forum, Moonlighter. Lots of info there that might interest you. Here's the link to that thread Suzuki NMEA 2000 newtork + standard Suzuki gauges - it can be done - The Hull Truth - Boating and Fishing Forum

[Mawrob]

Thanks Mike. I found that too and it has some interesting info. It is what led me to think that perhaps the ECU recall had something to do with the new firmware not matching the flow meter.

[Moonlighter]

Hi guys

I am not sure it it will help, but anyone who wants the latest software updates for the SMIS gauge and for the Suzuki engine interface is welcome to email me and I will send them to you. Version 2.5. Released earlier this year, I believe. Simple to install if you have a device on your network that takes a SD card.

Suggest that you check both devices to see what software version they are- network devices menu, select the device and you should be able to find the SW version detail there.

But the downside is that updating software will reset both devices, so you have to start over with settings, calibrating etc.

For Mawrob, the only suggestion other than that I can offer is voltage. These gauges can do weird things if they are not getting a good power supply. Since the SMIS are getting their power fom the network, check the fuse for the power node and make sure it is clean, tight and all wiring connections are solid and all wires and connectors are in perfect condition.

Failing that, try the hard reset. Failing that, send them back because they then must be faulty!

[Harper]

Thanks, Grant. My 4" SMIS gauge has version 2.5 software, and is coupled to the new 990C0-88146 interface cable. Will still be working on that fuel calibration as soon as I can get back on the water.