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General Information => FAQ/Tech Tips/Please Read First => Topic started by: bgrunhaus on August 01, 2012, 11:42:03 pm

Title: Definite tach solution for a, sorry, ANY diesel engine
Post by: bgrunhaus on August 01, 2012, 11:42:03 pm
Hello guys!

i belive in giving, you know, you've gave me so much(the forum and all of your contributions)

here's the info:

i want a tach on my diesel! dont we all?

i started reading and reading and reading and didnt find anything concrete!

so i decided to do it myself

i had a Crankshaft position sensor of a VR6, found the pinout online and is like this

with the two notches pointing up terminals are 1 2 3
1: 12v input
2: tach output(here you connect the tach)
3: ground

so as instructed you have to provide the 12v( better to be switched, so take it from the shut off solenoid), the ground from wherever and send a cable from the tach to the #2 terminal on the plug of the CPS.

add two nuts to the damper, welded glue whatever you like, build a bracket and that's it!

there you go!

here's a video! it's in spanish but is self explanatory! http://www.youtube.com/watch?v=DpT7qOaRco0 (http://www.youtube.com/watch?v=DpT7qOaRco0)

let me know what you think!
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on August 01, 2012, 11:48:10 pm
http://www.vwdiesel.net/forum/index.php?topic=30442.0 (http://www.vwdiesel.net/forum/index.php?topic=30442.0)
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on August 01, 2012, 11:48:24 pm
i built that a LONG time ago..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: 8v-of-fury on August 01, 2012, 11:58:15 pm
Very well done, on both accounts. They will BOTH be added to the FAQ sticky. Kev, you probably weren't the first ever ;)lol.
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on August 02, 2012, 12:08:22 am
Very well done, on both accounts. They will BOTH be added to the FAQ sticky. Kev, you probably weren't the first ever ;)lol.

not saying i was the first.. but i was one of the first to openly confirm that it works.. and that it is very easy to accomplish..

i KNOW i was not the first, because ford used to drive their tachs off a mag pickup as well..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bgrunhaus on August 02, 2012, 11:17:29 am
Is not that hasn't been done till now! You did it and probably a lot of guys out there have solutions too!

my contribution here is to give detailed instructions on how to wire the sensor and where to source it.

i stated that i used a volkswagen VR6 crankshaft position sensor but thinking about it the CPS of an ABA engine can be used too!

ill post an update as soon as I get the cluster tach(the cluster was changed by the PO, it now has a gas cluster) working!


Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: 8v-of-fury on August 02, 2012, 11:39:22 am
So that would power the green wire of any typical gas tachometer correct? Coooolio :)
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on August 02, 2012, 01:34:06 pm
So that would power the green wire of any typical gas tachometer correct? Coooolio :)

same thing with the one i built Jer.. negative side of coil to ground. positive side to tach exciter wire.. cool thing about a mag pickup, is you cant wire it wrong..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bbob203 on August 18, 2012, 04:01:44 pm
So this will drive a gasser mk2 tach for sure???
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on August 31, 2012, 06:44:21 pm
So this will drive a gasser mk2 tach for sure???

in a round about way.. ive never gotten my sensor working with a stock mk2 tach.. someone has tho..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bbob203 on August 31, 2012, 09:01:00 pm
So this will drive a gasser mk2 tach for sure???

in a round about way.. ive never gotten my sensor working with a stock mk2 tach.. someone has tho..

I'm not much with electronics. Does it require some sort of way to increase/decrease voltage or amperage/change frequency?
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on September 01, 2012, 03:17:32 pm
So this will drive a gasser mk2 tach for sure???

in a round about way.. ive never gotten my sensor working with a stock mk2 tach.. someone has tho..

I'm not much with electronics. Does it require some sort of way to increase/decrease voltage or amperage/change frequency?

i dont know dude.. ive never gotten my setup working with a stock mk2 tach..

i remember something about having to use a magnetic pickup, and magnets to signal it from the crank..

just a chunk of steel doesnt make enough of a voltage spike to signal the stock tach..

that is all i know about it for now. i know mine works great with my 4" autometer tach..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bbob203 on September 01, 2012, 03:21:36 pm
only reason i care so much i can get a gas cluster for a dime a dozen diesel way more $$$
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on September 01, 2012, 03:23:34 pm
only reason i care so much i can get a gas cluster for a dime a dozen diesel way more $$$

dakota digital tach converter..

hook the W terminal from your alt up to it, hook the green wire from it to your tach..

adjust tach for correct reading..

done deal.
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: jimbote on November 04, 2012, 06:36:19 pm
Very well done, on both accounts. They will BOTH be added to the FAQ sticky. Kev, you probably weren't the first ever ;)lol.

not saying i was the first.. but i was one of the first to openly confirm that it works.. and that it is very easy to accomplish..

i KNOW i was not the first, because ford used to drive their tachs off a mag pickup as well..

dang.... look what I found :D .... post 29!!....  http://www.vwdiesel.net/forum/index.php?topic=3741.15
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on November 06, 2012, 02:17:05 pm
i believe im going to play around with my setup a bit more today..

see if i cant get a tach reading from my cluster..

i know the cluster is good..
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: snakemaster on November 08, 2012, 04:37:02 pm
i used the crank pickup on my 1z mtdi ,its in a gasser 2.5 t4 transporter ,but now a mtdi wired up the sencer power from pump sol, and run the wire from no 2 pin to the gas taco , and have my  aftermarket diesel taco on to the w T , to compare gass taco on idle, reads 900rpm and the W one reads 650rpm m van dose ldle low. and  gaser at 3000rpm W at 2000rpm , tryed a small capacitor in line from no 2 pin  then a bit biger one ,just the same , need some way to get the  frequency down . i am not in to  electronics things bobers, but some one may be able to shed some light on this .
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on November 14, 2012, 06:57:14 pm
you positive your diesel tach is accurate?

i would lean more towards the gasser tach being accurate...

if its raining too hard, the diesel tach is in-accurate, and thats not cool..

my old audi 5000TD, the tach would quit working whenever you hit a puddle in the road..

then the belt would dry, and the tach would come back to life..

Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: libbydiesel on November 14, 2012, 09:13:56 pm
The crank sensor on the AHU/1Z will give four pulses per rev.  The gasser 2.5 (5-cyl) tach will be looking for 2.5 ignition pulses per rev and thus the discrepancy.  A gas 4 cyl tach is looking for 2 pulses per rev.  I've been planning on using a flip-flop to cut the crank sensor output in half in order to drive a typical 4-cyl gasser tach. 
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bbob203 on November 14, 2012, 09:28:30 pm
The crank sensor on the AHU/1Z will give four pulses per rev.  The gasser 2.5 (5-cyl) tach will be looking for 2.5 ignition pulses per rev and thus the discrepancy.  A gas 4 cyl tach is looking for 2 pulses per rev.  I've been planning on using a flip-flop to cut the crank sensor output in half in order to drive a typical 4-cyl gasser tach. 

whats this flip flop you are talking about?
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: libbydiesel on November 14, 2012, 09:48:30 pm
It's one of the most basic logic circuits.

http://en.wikipedia.org/wiki/Flip-flop_%28electronics%29
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: bbob203 on November 14, 2012, 10:45:33 pm
After reading some of that I short circuited. lol.. What would one use to implement a flip flop circuit to do what your describing to cut the 4 pulse signal into 2?
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: ORCoaster on November 14, 2012, 11:09:51 pm
I've been planning on using a flip-flop to cut the crank sensor output in half in order to drive a typical 4-cyl gasser tach. 


Well it might be this type of flip flop.  (http://i1087.photobucket.com/albums/j475/Orcoaster/Diesel-Flip-Flops-.jpg)
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: snakemaster on December 23, 2012, 05:44:14 pm
aaa some info there would this flip flop do http://www.ebay.co.uk/itm/FLIP-FLOP-D-TYPE-SMD-74LVC1G175-Part-SN74LVC1G175DBVT-/390460792223?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5ae946dd9f

or can i buy a set up ready to go , we have maplines , and rs hear , no rado shack  :)
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: libbydiesel on December 25, 2012, 12:35:02 am
I'm not particularly electronics savvy, but I think that would work wired correctly. 
Title: Re: Definite tach solution for a, sorry, ANY diesel engine
Post by: R.O.R-2.0 on December 25, 2012, 02:15:49 pm
anyone have any idea about modifying the stock mk2 tach to accept a signal from a mag pickup?