Guage Replacement (mdc removal) questions

[Sammamish Skier]

My guages are super flaky. Hit a small wave, and the gauges go kaput. I'm going to go through the the debug/cleaning procedures, but I'm wondering if anyone has removed the MDC completely, and if so did you have to make any sender changes?

I've searched through the forums, and not found any info.

[Wet-N-Frugal]

If they all go erratic at once, I strongly suspect undervoltage into the MDC. The standard fix that has worked for many of us is upsizing the wire runs from the battery to the dash. Run a second #10 wire for both the Battery+ and Battery-.  Further, which may be just as important, is improve the power bonding nodes (where the main power wires distribute to the local devices). I introduced two new #10 or #12 Stainless Steel screws (one for plus and one for minus) protruding down out of the inner dash pocket; use two nuts: one to hold the screw, and the second to captivate the wires/rings. Cut off the old rusting ring lugs, and attached new ones. The end result is a very inexpensive, santitary interconnect.

A Second Battery with Isolator is another excellent step.

-WNF-

[Capt Rick]

99 boats don't have a DECC to control accessories. The issue is the MDC get wet from sped o hose and kills the circuit. Suggest unplug and clean each pin connector. 
Plug the hose for the speedometer and use a phone app for speed.

MGA0010911   MDC,1999InstrumentationCompute,Early7GaugeDash,99,00MY   $449.00
There are only a 2- MDC left .

A good project would be a change all switches and gauges to Analog gauges w/o computers and Digital switches.

Capt Rick

[Sammamish Skier]

That's the project I'm contemplating.  Does anyone know if the tach/oil senders in our motors are analog compatible? The rest of the guages should be simple assuming I can find ones that look good in the dash

[FreeLance]

How many computers do our boats have and what do they all do?  Is there a specific one that is most important that allows the egine to run and all of the others are nice to have but would not doom our boats if they failed?

[ATXChris]

@FreeLance There is an Toyota ECU that controls the engine and it is rock solid, you rarely hear of issues.  The MDC is the guage cluster computer and 2000+ year boats have a DECC ( which may be considered more of an electronic switching unit than a computer.

@SammishSkier I would recommend cleaning out the connections to the MDC with electrical parts cleaner as mentioned by Capt. Rick.  The fact that problems are intermittent leads me to believe your problems are all connection related.  Once you get that fixed as well as good power and ground connections those guages should be solid.  The pitot speedometers are kindof flaky just due to their design so you can either use the smartphone app if you're cheap or upgrade to perfect pass speed control or their just gps speedometer ( which both fit right in to the dash ).

[FreeLance]

Thanks ATX!

Would it be a possible solution to use a bluetooth ODBII sensor connected to the port on the engine and run the gauge information on your phone using Dashboard Command or Torque?

[skibeau]

I got no clue dude, but it's an awfully creative idea. I like it!

[Capt Rick]

The  senders are analog. The tach is off  a 4 pole signal a direct connect to the wires under dash for oil, water and fuel, and alarm can go to a standard  analog  gauge.
 Then you would get remove the Digital Display unit. The MMDC and the MDC both change signal from Analog to digital.


The switch's need a panel made with Circuit breakers( or inline fuses)  and switches to plug into white harness plug. I guess to have a kit ready for the accessory controls first.

[toyotafreak]

This is the thread I always come back too: http://www.epicmarine.com/forum4/index.php?topic=2188.0

That was back in '12...not sure what ended up with it.

I still only have low voltage readings/alarms, and neither have been bad enough to get me off the couch.

[ATXChris]

@FreeLance Unfortunately the Epics are not OBDII compliant even though the connector is the same so the OBDII tools typically won't work.  The only way to read data off the diagnostics port is with the Toyota scan tool ( talk to Capt Rick if you are interesting in renting ) or to use Techstream in Japan region mode ( search the forums for more info on this ).

[Sammamish Skier]

The  senders are analog. The tach is off  a 4 pole signal a direct connect to the wires under dash for oil, water and fuel, and alarm can go to a standard  analog  gauge.
 Then you would get remove the Digital Display unit. The MMDC and the MDC both change signal from Analog to digital.


The switch's need a panel made with Circuit breakers( or inline fuses)  and switches to plug into white harness plug. I guess to have a kit ready for the accessory controls first.

That's great info. Thanks! Should make rewiring easy.

Going to try to find the bad connection in my dash first, and if that doesn't resolve it, the search will start for guages that look as good as the ones Toyota originally installed

[Sammamish Skier]

Update on this. The new gauges are in, and function very well, I have a bunch of pictures of the installation I need to post when I get a chance.  If you are going to try this, expect it to take a couple of days to do the install unless you are a whiz at making wiring harnesses.  While I was at it I removed the #10 power and ground and replaced them with 6guage wires, so that made the job take a bit longer.

The overheat/low voltage alarm is now going off, anyone have any recommendations?  Should I buy a new alarm module?  I'm wondering if the alternator is hosed as the battery reads 13.8v with the engine running. I'm used to 14.6 in a 12v system.

[Capt Rick]

MEM0010806   Alarm,Engine,PlugInType,OldStyleDash,99MY,12v           108.33    $15.00 

[cyclone]

Tach is a two pole (2ppr) signal there Capt Rick dude. I know because of what I did to help Perfect Pass implement their system on our boats. Use 4 cyl mode for an aftermarket tach.

If you are reading 13.8 vdc at battery your alternator is good. If it croaks, don't use an auto one, they fall apart in 6 months, or at least mine did. Get old one rebuilt.

Might try the obd2 to bluetooth, cellphone to ipad to satellite to home stereo connection in stealth Japanese mode, I know some of the ancient art of Karate, maybe my nunchuck skills will help. Or bowhunting skills.