Mercedes Om617 with tachometer(fix?) Using alternator.

Discussion in 'General Tech' started by Fortitude4wd, Oct 14, 2018.

  1. Fortitude4wd

    Fortitude4wd

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    I had a heck of a time finding any information on this subject. I'm doing an om617 swap and am using the Dakota digital dsl-1e unit. In order to get a signal from the alternator you need a "w" connection, well the stock Benz alternator and the Saab 900 alternator don't have one stock so you need to make your own. This is kinda a how to, but really just putting the info out there to help anyone else who needs it.

    You got to install a "w" wire to get the reading for the Dakota digital. From what I gather the wire is a connected straight to one of the windings before regulator (uninterrupted a.c. current) so I soldered a wire to the winding. Ran the wire out a hole in the back of the casing. Put a vacuum hose around it to keep it from chafing. And connected it into the Dakota digital unit.

    I say fix? Because the unit is getting a signal and my tachometer moves but i have yet to get it calibrated correctly to the point of accuracy. If I get it working I'll update this post. And if I can't get it I'll delete it. Anyone want to correct me on it and I'll learn something.

    My truck is a 1986 4runner with the turbo gauge cluster (analog)

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    RoaringFork likes this.
  2. Fortitude4wd

    Fortitude4wd

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    Update: it works. I can't believe it took me so long to get it right, my issue was wiring the Dakota digital, having to jump the "none used" position with the "high power" position. So confirmed way to make a om617 work with the stock sr5 gauges with 22re.

    The rats nest is all cleaned up now

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  3. Rainy Day FZJ

    Rainy Day FZJ

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    Can you please show how the Dakota is hooked up to the OEM wiring? I'm almost finished with the exact same swap, and am about ready to dive into this. I have removed all of the un needed wiring from under the hood. IE distributor, Injector wiring, etc.
     
  4. Fortitude4wd

    Fortitude4wd

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    Rainy day fzj. I didn't use any of the truck wiring to make the tach work. I made and ran each individual wire for the swap.

    To find out what position is the "tachometer" on the 3 connectors on the back of your dash, just look in the fsm or find it on a another thread.

    The best I can do is show you a picture of a drawing. I made.
    The hardest wire to make is the "w" signal wire from the alternator like I showed above.
    The rest just run them from wherever you can get a 12v and ground the easyiest

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    Rainy Day FZJ likes this.
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