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12 V92 Ta's and DDEC, no throttle in gear on one engine..

Discussion in 'Engines' started by captsam54, May 27, 2012.

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  1. captsam54, Jun 1, 2012
    #21
    captsam54

    captsam54 Member

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    Going to do a test today... Replace the fried batt w/a brand new 8D.. That should give me 25/+ volts across the board.... I have a portable 12 volt charger that I can top them off and see what my DDEC will get from that...
  2. Pascal, Jun 1, 2012
    #22
    Pascal

    Pascal Senior Member

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    I dont understand why you feel you need a portable charger! Your alternators should keep the batteries charged. Have you checked them? After start up bring them to fast idle or whatever is needed for voltage to rise

    Just disconnect the charger output to the engine batteries, the batteries should hold their charge if the alternators work. If the boat sits for more than a few days, turn off the batt switches.
  3. captsam54, Jun 1, 2012
    #23
    captsam54

    captsam54 Member

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    Thanks.. don't think I have to disconnect the charger leads from the batteries as they go thru the equalizers and Ignition.. Did you see the schematic?? Here is the legend.. Also just using the charger to top them off, 1) because we are not running anywhere at the moment, 2) because the constavolt is shot.

    I will be checking my alternator output.. LOL. and other sensor issues I am having w/ the DDEC system....

    Attached Files:

  4. Bamboo, Jun 1, 2012
    #24
    Bamboo

    Bamboo Senior Member

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    Off topic a bit here but what year did DDEC come out? '89?
  5. Jimbo1959, Jun 3, 2012
    #25
    Jimbo1959

    Jimbo1959 Member

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    DDEC 1,2, or 3

    Which version of DDEC are you running? The ecm's have different fuse locations and sizes.
  6. Capt J, Jun 3, 2012
    #26
    Capt J

    Capt J Senior Member

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    The house batteries are relevant. DDECs are very finnicky to a varying power supply and if they don't get un-interrupted voltage when the engine is turning over, they will not start. So typically the DDEC (computers) are wired to a different power source than the starting batteries, such as the house batteries.
  7. captsam54, Jun 4, 2012
    #27
    captsam54

    captsam54 Member

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    Yes.. It all comes in at the equalizer feeds.... And the operating voltage for the DDEC system is 12 volts....

    I heard recently form another Capt. that they switched to 24 on the last version because the 12 took so much power from the alternators..

    I replaced the battery that had the low voltage... And now my DDEC will shift and throttle up in gear.. Also my La Marche 24 volt constavolt appears to be working semi correctly again....

    Is operating around 28 amps out and the batts show a voltage of 31.1 etc.

    So it all comes down to Really good batteries and voltage to operate the DDEC system....
  8. Pascal, Jun 4, 2012
    #28
    Pascal

    Pascal Senior Member

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    "batts show a voltage of 31.1 etc."

    that sounds VERY high to me! i usually see around 26v with the engines running (Cat 3412Es). Is that with the charger on or just on alternators?

    at 31v, you're going to cook those batteries in no time.

    i really dont' like needing a house bank to power engine controls, lousy set up from a reliability stand point. a better option would be to have a dedicated battery feeding the engine controls.
  9. Capt J, Jun 4, 2012
    #29
    Capt J

    Capt J Senior Member

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    Do not use your current charger. The voltage is too high on DC, and I can bet you money that if you put your meter on AC voltage that the charger is leaking a lot of AC voltage through due to a bad diode, which will cause batteries to grenade when you try to start them. I had this happen on a boat I managed a long time ago, the DC was a touch high (not what you're seeing) but around 27.6-28.1 volts, and when the owner tried to start the boat it literally grenaded 2 batteries with pieces strewn ALL OVER the engine room.....The charger was leaking around 100 volts AC through it.........I would get a new charger, and change batteries in banks, not just 1 from a bank or so forth.......

    At least DDEC controls are not nearly as unsafe as the old microcommanders with low voltage. The DDEC's will usually not stay in gear like you're seeing. The old microcommanders with low voltage would usually go in gear on their own, and accelerate and all kinds of crazy things I've seen.......
  10. captsam54, Jun 4, 2012
    #30
    captsam54

    captsam54 Member

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    Yep, It's a frickin nightmare... I use the constavolt to juice them up about a minute before starting then cut it off.. Want the boss to get a new one or have someone in the know look at it.. I half ass know what a diode looks like but can't tell one end from the other... It will drop down to 24 volts if I leave it on for a bit.. But it will start out at 46 or so and then drop down.. But the batt voltage goes up...
  11. captsam54, Jun 11, 2012
    #31
    captsam54

    captsam54 Member

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    Well, checked and cleaned all the grounds and swapped some of the sensors from engine to engine...

    Did a start up but I get the same readings, fault codes.... PORT. 61, coolant pressure, 48, fuel pressure low, 41,timing reference sensor.. STDB. 43, coolant level low.. 42, sync ref sensor.

    Going to do a sea run tomorrow and see what happens off the dock..
  12. Capt J, Jun 11, 2012
    #32
    Capt J

    Capt J Senior Member

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    It sounds like a circuit board is fried.
  13. Capt Ralph, Jun 11, 2012
    #33
    Capt Ralph

    Capt Ralph Senior Member

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    What symptoms have changes? What symptoms did not move? What symptoms are new (induced)?
    Moving stuff around and not noting what has changed is not help you or helping anybody helping you.
  14. captsam54, Jun 12, 2012
    #34
    captsam54

    captsam54 Member

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    LOL, nothing changed.. Still identical codes.. So It's apparently not some of the sensors.. Have some different tests I want to do today running offshore for a bit and we will see...
  15. captsam54, Jun 12, 2012
    #35
    captsam54

    captsam54 Member

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    AHH but what board....?/ I can start pulling the covers off the modules and looking for burn marks....
  16. Pascal, Jun 12, 2012
    #36
    Pascal

    Pascal Senior Member

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    The first thing you need to fix is your charging problem. Those voltage spikes are the primary suspect to all your issues.

    Did you ever check your alternators output? Again this is key to good voltage underway
    You have to stop using that questionable charger... You know it s bad. This is why checking your alternators is important

    With all these problems I m not sure I d take the boat out for a sea trial... It s not like your chasing a power or fuel problem and need to be under load.

    I know getting parts thru customs can be a pita in the islands but not replacing that old charger is costing you a lot more than ordering a new one and shipping it over.
  17. captsam54, Jun 12, 2012
    #37
    captsam54

    captsam54 Member

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    Thank you for the reply... I am asking the owner for a new Charles 24 volt 60 amp charger, which he can bring on the plane from Lauderdale.... He wants me order a diode and solder it in and all will be fine.. (LOL. which one where??) It's a nightmare in there and I would not know where to start... (see pic)

    I am testing the alternators today and if all is correct, I will go out in ft. of the marina and do some under load testing...

    Now.... I only use the 24 volt charger to boost initial charge into the batts for cranking... I turn it off before I turn the ignition switches.. Now there are systems that do run off the 24 volts.. Blowers etc. but nothing that directly affects the engines after starting... The DDEC 3 system I have runs off the 12 volt batts and thru the load equalizers...

    Doing some inspecting and cleaning of terminals of the ERIM.. and the 2 engine MM's... So far they look fine... But you never know.. A little contact spray and checking connections..

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  18. Pascal, Jun 12, 2012
    #38
    Pascal

    Pascal Senior Member

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    i see a lot of rust and corroded terminals in that picture... this is where you have to start.

    some of those cables (the green pair in the middle, and the red and blacks on that rust block in the bottom look like they're solid copper.

    seems like this picture explains the owner's reluctance to replace the charger :)
  19. Marblehead01945, Jun 12, 2012
    #39
    Marblehead01945

    Marblehead01945 Member

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    Whats the board in the lower right corner of the picture? There may be a diode on there that we can't see but I don't see any in the picture.
  20. captsam54, Jun 12, 2012
    #40
    captsam54

    captsam54 Member

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    Here's a better picture of that board,and yes there are Diodes on it.. The owner knows this was sprayed w/ saltwater 2-3 years back... The boat was built in 98, but this La Marche Constavolt techonology is from the 70's....

    Attached Files:

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