Ociliscopes + W signal = universal tach converter/controller - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• Ociliscopes + W signal = universal tach converter/controller by Smokey Eddy on 14 Nov, 2008 01:03
• Could an oscilloscope be used to determine the conversion needed to make a universal converter controller that will make any gasser aftermarket tach work off the "W"?
  
  
  I have an oscilloscope and some knowledge on signals, frequencies, electronics and programing but i just am unfamiliar with what the "w" signal actually is...
  
  is it the frequency of the alternator doing 1 complete revolution?
  
  I feel confident i could program a controller to do this that you would simply add to the alternator to make it usable for aftermarket tachs.
  
  but i need to know what im dealing with off the bat. If anyone could explain what the W signal is I'd appreciate it. I don't want to get into schematics of the alt. and all that if someone already knows.
  
  Thanks! I hope i produce something useful.
  
  
  If no one knows i can figure it out but it would save me a lot of time if someone already knew. Thought i'd ask.
  
  
  I have NOT looked for vw vortex for something like this.
• #1 by blackdogvan on 14 Nov, 2008 09:00
• Dude, check out the Dakota Digital diesel tach modules. Cheap & easy.
• #2 by blkboostedtruck on 14 Nov, 2008 09:07
• you will end having a converter box in the end some should have the link to roger brown's site that should answer all your questions ! i have one of his kit also he sells them!
  Duane
• #3 by Vincent Waldon on 14 Nov, 2008 10:12
• http://www.vwdiesel.net/phpBB/viewtopic.php?t=13499&highlight=terminal
  
  for starters. :wink:
• #4 by Smokey Eddy on 14 Nov, 2008 10:21
• Ooooooooooooo
  thanks guys
  hahaha
  
  
  (would still be neat to see it on the scope)
• #5 by Smokey Eddy on 14 Nov, 2008 10:26
• I'm thinking now after reading your thread vince, that there is something screwy with my W terminal....
  
  
  when contacted with my tach it reads nothing. If i graze the terminal with the wire the tach will flutter about. At no setting on my tach will it read something useful. What does this sound like?
  
  I just thought the W was putting out something totally un-usable. Not just simply different V and frequency.
  
  Is my alt. unusable?
  
  ps. I've seen the digi ones before but i already have the tach and i wouldn't want a digital read out. numbers are so arbitrary and deceiving.
  
  pps. I did use the search on here and i couldn't find anything useful...
• #6 by 53 willys on 14 Nov, 2008 10:45
• this probably wont help..but I thought I would throw it out there...I have to goose my accelerator pedal to get my W terminal to read..basically you need to "excite the alt" on my car...the guys on here say that normal....mine has to be "excited" every time I turn the car off and then back on...does not matter if it's warm or cold...
• #7 by Smokey Eddy on 14 Nov, 2008 10:51
• so when you're idling at a light it will read 0?  :?
  i think im confused...
• #8 by 53 willys on 14 Nov, 2008 11:05
• Quote from: "Smokey Eddy"

  so when you're idling at a light it will read 0?  :?
  i think im confused...

  
  when I start the car it reads zero until I step on the gas pedal...then it reads after that...but it reads low..
• #9 by Smokey Eddy on 14 Nov, 2008 11:22
• oohh
  weird... I never tried that i just tried to get an idle to read. I'll have to try that when i put it back together. You use a converter or a VDO diesel tach?
• #10 by 53 willys on 14 Nov, 2008 11:56
• Quote from: "Smokey Eddy"

  oohh
  weird... I never tried that i just tried to get an idle to read. I'll have to try that when i put it back together. You use a converter or a VDO diesel tach?

  
  yeah that would suck if it just needed to be "excited" and you didn't know..
  
  I'm running a motometer diesel cluster with stock tach....mine came from Tyler in Canada so it's KPH right now...but I'm gonna swap in my old MPH speedo...soon