Go Back   TeamTalk > Maintenance Tips, How-tos and Refurbishing Topics > Electrical

Reply
 
Thread Tools Display Modes
  #1  
Old 08-14-2012, 01:24 PM
Spimbo Spimbo is offline
TT Newbie
 
Join Date: Jul 2012
Boat: Mastercraft, Maristar, 2004 Indmar 350
Location: Northeast
Posts: 7
Mmdc

I have a 2004 Maristar and am having the following issues, which all showed up at teh same time?
1) SPEEDO INOP
2) CHECK ENGINE LIGHT COMES ON, AND AUDIBLE ALARMS SOUNDS FOR 2 MINUTES.
3) RADIO INOP

My votgage gage is only reading 10.5v, even thou i just replaced the batter. I understand that the system in teh boat will shut down the radio if and when the voltage guage reads below 11.5v. This is to ensure you hear the low battery alarm that sounds. I am thinking the issue is the MMDC, but wanted to get your thoughts? And any way , short of replacing it, to test the MMDC?
Reply With Quote
  #2  
Old 08-14-2012, 04:31 PM
ricford's Avatar
ricford ricford is offline
MC Fanatic
 
Join Date: Feb 2011
Boat: 1996 Prostar190
Location: Muskoka, Canada
Posts: 552
Use a multimeter and check the voltage across the battery. When boat is off, it should read about 12V. With the engine running it should be around 13.5V or so. If it's reading low when running I would guess alternator.
Reply With Quote
  #3  
Old 08-14-2012, 04:34 PM
ricford's Avatar
ricford ricford is offline
MC Fanatic
 
Join Date: Feb 2011
Boat: 1996 Prostar190
Location: Muskoka, Canada
Posts: 552
Truth is, I only clicked this thread to find out what an MMDC was. I guess I still don't know.
Reply With Quote
  #4  
Old 08-14-2012, 05:22 PM
Spimbo Spimbo is offline
TT Newbie
 
Join Date: Jul 2012
Boat: Mastercraft, Maristar, 2004 Indmar 350
Location: Northeast
Posts: 7
Multiple Module Data Computer - MMDC.
Reply With Quote
  #5  
Old 08-14-2012, 09:09 PM
ricford's Avatar
ricford ricford is offline
MC Fanatic
 
Join Date: Feb 2011
Boat: 1996 Prostar190
Location: Muskoka, Canada
Posts: 552
Ahh. I'd still start with the alternator. You can remove it and have it tested at a motor rewinding shop.
Reply With Quote
  #6  
Old 08-14-2012, 09:27 PM
Spimbo Spimbo is offline
TT Newbie
 
Join Date: Jul 2012
Boat: Mastercraft, Maristar, 2004 Indmar 350
Location: Northeast
Posts: 7
Yep, did that, in fact i changed the alternator, but no joy...
Reply With Quote
  #7  
Old 08-14-2012, 10:40 PM
ricford's Avatar
ricford ricford is offline
MC Fanatic
 
Join Date: Feb 2011
Boat: 1996 Prostar190
Location: Muskoka, Canada
Posts: 552
The computer would be the last thing I would change, because of the cost. Next I would remove and clean all the connections from the battery to the alternator, and starter. Also do the ground at the battery and the block. Then check your voltage with a multimeter. Don't trust the voltmeter on the dash.
Reply With Quote
  #8  
Old 08-15-2012, 10:36 AM
bturner2's Avatar
bturner2 bturner2 is offline
MC Devotee
 
Join Date: Mar 2008
Boat: Maristar 200VRS w/ X2 Package, 2007, 310HP
Location: Brighton, MI
Posts: 2,292
MDC should have no effect on voltage and typically when you have a problem it's with gauges not working at all. I'm thinking grounding which tends to be the number one culprit. Start at the block and clean every connection, check every connector for condition to see if you have corrosion or a loose connection. Work your way from the engine (the ground source) to the battery then to the dash. Not fun but it's typically where you'll find the problem.
Reply With Quote
  #9  
Old 08-15-2012, 10:31 PM
Spimbo Spimbo is offline
TT Newbie
 
Join Date: Jul 2012
Boat: Mastercraft, Maristar, 2004 Indmar 350
Location: Northeast
Posts: 7
I have check the ground on the block to the battery. I will check to the dash. i agree, it just does not seem like the MDC to me.

Thanks!
Reply With Quote
  #10  
Old 08-16-2012, 07:50 AM
bturner2's Avatar
bturner2 bturner2 is offline
MC Devotee
 
Join Date: Mar 2008
Boat: Maristar 200VRS w/ X2 Package, 2007, 310HP
Location: Brighton, MI
Posts: 2,292
As you're probably aware you're basically looking for where the voltage drop is occurring. If you have 12 volts at the battery and 10.5 at the terminal block under the dash somewhere between the two points you're dropping 1.5 volts. Running temporary wires for ground and hot (one at a time) and checking voltages for change will tell you which of the connections is having issues.

Like wise eliminating circuits and checking voltages will help in determining if you have a short that is drawing down the voltage. I've heard that bad diodes in the alternator can cause some weird electrical issues but it sounds like you've already eliminated that.
Reply With Quote
Reply

Tags
mmdc, speedometer

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 10:32 PM.