Replacing the MMDC with Analog Gauges

@mikey18605 Now that @ttmott has defined what your calling an MMDC (btw where did you get that term?) as an Instrument Interface Module, here is the link to a new instrument interface module: https://www.sbmar.com/product/qsm-11-instrument-interface-module-12v-4078297/
The "MMDC" is illustrated on the SR schematics - you can see it on what I attached. Is it the same as what Cummins shows on their schematics as an Instrument Interface Module?? I say yes it is...
 
The "MMDC" is illustrated on the SR schematics - you can see it on what I attached. Is it the same as what Cummins shows on their schematics as an Instrument Interface Module?? I say yes it is...

Yeah I saw the port/stb engine to MMDC as signals but didn't see any other reference to MMDC. But to your point, they do lead to the IIM. Curious why the name is changed like that. But the industry name seems to be Instrument Interface Module.
 
Yeah I saw the port/stb engine to MMDC as signals but didn't see any other reference to MMDC. But to your point, they do lead to the IIM. Curious why the name is changed like that. But the industry name seems to be Instrument Interface Module.
I would guess that Sea Ray had some features added / removed from the Instrument Interface Module and thusly call it a MMDC. Essentially and physically they are probably the same BW units; just a different "dash" number.
 
Been following the thread because this sounded vaguely familiar but could not put my finger on it.
Until @ttmott diagrams and last few posts.
MMDC stands for "Multi-Module-Data-Controller" and essentially it should be the IIM
I was a ASE Master truck tech at Freightliner many moons ago and worked the early Detroit, Cat and Cummins electronic controlled engines and trucks.

The engines were going electronic, but the cabs all still had analog gauges. There were no digital "glass" displays yet nor mechanical gauges that were direct digital driven.

Freightliner had the similar issues described her. No gauges, no waning lights. Are you certain the IIM is dead? How did you determine that? For us the MMDC also had built in pressure transducers for the air brake systems. So if the engine information stopped, BUT the air warning system worked we could assume the MMDC was working.

That left CAN signal loss. Frieghtliner had two issues here, the cabs are air-ride, and sit on air bags and rubber hinges so isolated from the chassis. Ground was very important. Loose or corroded grounds to the cab would introduce noise on the CAN bus and cause loss of timing/signals. Second was some poor quality, outside the cab all connectors were Deutsch water proof connectors. But in the cabs they had some none water proof connectors that would get corrosion. And a quality issue were the pins were not fully seated and would back out a little from vibration, losing connections.

Ours looked like this, note also made by Medallion, the ports on the bottom were the air lines.
508062pica_394x.jpg
 
Thanks to all for their endeavors to understand my problem and the easiest way to deal with it. I plan on going to analog helm gauges. The issues are where to put any sensors, as the advice TO NOT USE existing sensors is valid. The one yet to be solved is a temp sender. I see a 3/8NPT plug on the circulating pump that should work. Any other thoughts?

T H A N K S A G A I N T O A L L F O R T H E H E L P!!!!!!!!!
 
Thanks to all for their endeavors to understand my problem and the easiest way to deal with it. I plan on going to analog helm gauges. The issues are where to put any sensors, as the advice TO NOT USE existing sensors is valid. The one yet to be solved is a temp sender. I see a 3/8NPT plug on the circulating pump that should work. Any other thoughts?

T H A N K S A G A I N T O A L L F O R T H E H E L P!!!!!!!!!

So let me ask you another question, what makes you think, after everything that has been said here, that you can actually connect an analog gauge to anything in the current configuration?

As mentioned it doesn't look like you can do this.
 
Yeah I saw the port/stb engine to MMDC as signals but didn't see any other reference to MMDC. But to your point, they do lead to the IIM. Curious why the name is changed like that. But the industry name seems to be Instrument Interface Module.
Good questions -
He stated that he was going to install a set of sensors on the engines (oil pressure and coolant temperature) but there are things standard gauge sensors cannot accommodate like -
Engine Fault Alarm - Buzzer that is activated by the MMDC
Intake Manifold Temperature - Visual Alarm activated by the MMDC
Low Coolant Level - Visual Alarm activated by the MMDC
High Oil Temperature - Visual Alarm activated by the MMDC
Alarm Cancel - Momentary Switch interfaced with the MMDC
Tachometer - Pulse data - provided by the MMDC
Plus other optional things like water in fuel, gear oil pressure, low bat voltage that the MMDC provides.

His boat and best wishes he gets it all straightened out.
 
The addition of sensors for analog gauges is a simple task. Oil goes to a "T" on the engine manual gauge. temp in one of several 3/8" or 1/2" bungs at the pump area. Tach goes to either the "W" or "R" terminal on the alternator.

The Instrument Interface Module sold by SBMAR is not compatable with the Borg Warner MMDC and unique gauges used by Sea Ray from 2000? to 2005?. Their are likely many early Sea Rays with QSM11 engines that are vunerable to this same failure and will have to go with Analog Gauges.

Of all the many statements made on this thread, only TTMOT knew the real deal, THAMKS!
 
Looking at Toms first schematic post, it looks like the engine ECM has J1939 on it. That can easily be converted to NMEA 2000 and go all digital dash. Another way to go.
I believe the J1939 you reference was for cross-engine communications for the C-Cruise system. I seem to remember a note about that somewhere.
 
@mikey18605
Before you start adding the senders and wiring I would pull your dash loose and get the model numbers off you gauges.

Because I think you are right and possibly wrong at the same time. You are right Sea Ray did not use the Cummins IIM they in fact used Borg Warner/Medallion MMDC and there is a significant difference between the two. All the MMDC are customized for a given purpose. The IIM and the MMDC I referred to for Frieghtliner were Digital to Analog. The Borg Warner is in fact the opposite it is a Analog to Digital convertor. Also different is the Sea Ray MMDC has two CAN input Port/Starboard AND one CAN output to the gauge clusters.

These gauges are NOT analog gauges, they are digital driven analog displays, very much like today's Mercury Smart Craft.
Below is a 2004 Borg Warner MMDC pinout diagram from Sea Ray. (2003 was not available)
It takes in digital from both engines, adds to that the analog fuel sensors and outputs digital to the gauge clusters.

To go true analog you may need to add the senders and change the gauges.
upload_2023-3-4_10-40-2.png
 
Thanks to all for the suggestions. I may not have mentioned that the 2003 48 SB I have has Digital Gauges via the Cummins ED-X made by SMX. Same has NEMA input from the Cummins ECM. All engine data is available but no "Fuel Gauge Info" is available, only total fuel used.The MMDC and gauges were a unique system via Borg Warner.
 

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