Ociliscopes + W signal = universal tach converter/controller

[Smokey Eddy]

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.

[blackdogvan]

Dude, check out the Dakota Digital diesel tach modules. Cheap & easy.

[blkboostedtruck]

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

[Vincent Waldon]

http://www.vwdiesel.net/phpBB/viewtopic.php?t=13499&highlight=terminal

for starters. :wink:

[Smokey Eddy]

Ooooooooooooo
thanks guys
hahaha


(would still be neat to see it on the scope)

[Smokey Eddy]

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...

[53 willys]

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...

[Smokey Eddy]

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

[53 willys]

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..

[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?

[53 willys]

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