Author Topic: Tach  (Read 106404 times)

Reply #45March 09, 2006, 10:31:49 am

regcheeseman

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« Reply #45 on: March 09, 2006, 10:31:49 am »
I know sod all about TDI's but i'd guess that there would be a better signal available than the one from the W term to drive a tacho. Bit of a pointless exercise converting to W term operation.
If you can find the tacho drive signal, I can help you make it work with the old dash.

Reply #46March 09, 2006, 11:03:01 am

RabbitGTDguy

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« Reply #46 on: March 09, 2006, 11:03:01 am »
i'm not using any of the TDI electronics, I'm using a mechanical pump, etc. so there is not ECU, etc.
I had played with the idea of using the crankshaft sensor that comes on the TDI...but from what I've read its a digital signal more than likely and I'd have to convert from digital to analog.

The other option is just to run the optical setup I have...
 
I'd like to make this early tach work either way though... either off the W, optically or even with the TDI's crank sensor (which I still have :) ) if it was at all possible...

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #47March 09, 2006, 11:38:47 am

regcheeseman

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« Reply #47 on: March 09, 2006, 11:38:47 am »
Run with the crank sensor, you need a digital signal - not an analogue one.

Go with the 4crawler optical circuit, it should be the same, except you have a factory sensor  :)

Reply #48March 09, 2006, 12:34:08 pm

RabbitGTDguy

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« Reply #48 on: March 09, 2006, 12:34:08 pm »
very cool...i'll have to see if it would work. I thought I'd have to have some sort of convertor to make it work...but it is possible that the TDI unit could work...and it'd be a "clean" install def. If it uses the same number of pickups... Rogers optical setup uses 4 pickups i believe...i'll have to count the cutouts on the VW sensor plate (on crank) to see how many it has. Would be cool if i could use it that way!

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #49March 09, 2006, 03:45:50 pm

mortskeg

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« Reply #49 on: March 09, 2006, 03:45:50 pm »
You're the man, regcheeseman!
Not that it must matter if it would get removed, but it looks like the C? has a 10.3 or a 103 printed on it, it is pretty faded.  The majic pink box is sans adjustment screw, unless it's on the bottom :P   It just has 2 terminals that go through the board.  The top is placarded 0,22K250-R1/  Thanks again for doing the interpretation/conversion post; hopefully it will be of some help to the US guys.   :D

Reply #50March 10, 2006, 04:18:04 am

regcheeseman

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« Reply #50 on: March 10, 2006, 04:18:04 am »
Quote
Rogers optical setup uses 4 pickups i believe...i'll have to count the cutouts on the VW sensor plate (on crank) to see how many it has. Would be cool if i could use it that way!


Four? Seem a bit odd.

I could imagine it having four zones on the detector plate to give 2 pulses per rev and thus match the normal input from the gasser's coil.

Can you link me to any information?

Chances are your engine will have a single pulse or possibly two or more or varying duration.

Reply #51March 10, 2006, 03:20:41 pm

mortskeg

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« Reply #51 on: March 10, 2006, 03:20:41 pm »
Not to step on GTDguy's toes- but maybe this is the link you wanted?
http://www.4crawler.com/Diesel/CheapTricks/Tachometer/index.shtml
Hope this helps. :)

Reply #52March 10, 2006, 06:21:12 pm

RabbitGTDguy

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« Reply #52 on: March 10, 2006, 06:21:12 pm »
i should have clarified i guess.... 4 on, 4 off. but thanks for posting the link, was about to do that here.

I'm just wondering if it could work on the TDI's sensor base, I'll take pics of it and it's pickup wheel here tonight...

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #53March 11, 2006, 10:37:18 am

johnny

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« Reply #53 on: March 11, 2006, 10:37:18 am »
This is the pic of a motometer gastach from a '86 mk2. I hope there is some similarity with the US-tachs so this can also be converted to work on a diesel.



Here is the big pic: http://gallery.vwcaddyforum.nl/albums/userpics/10067/gastach.JPG

Reply #54March 13, 2006, 03:38:11 am

fatmobile

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« Reply #54 on: March 13, 2006, 03:38:11 am »
That's the first one I've seen that doesn't used the SAK 215 chip.
 That looks like a texas instruments chip but I can't see the part numbers ....or get the big picture to fully load (bad dialup connection I think).
Tornado red, '91 Golf 4 door,
with a re-ringed, '84 quantum, turbo diesel, MD block

Reply #55March 13, 2006, 05:02:49 am

regcheeseman

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« Reply #55 on: March 13, 2006, 05:02:49 am »
Read the 4 crawler link and a lot of it seems hypothetical. Maybe his 4 pulse application worked but every 4 cylinder single coil motor I've ever worked on had 2 pulses per rev...

Oh no. I've just sussed it... probably should have read the text it may have been explained.

He was taking a signal from the injection pump and the injection pump runs at half engine speed hence doubling the pulses!

Let me know the TDI setup.

Johnny,

If you can photograph the other side of the board I may be able to help but I doubt it very much - it has the wrong chip.  :(

Reply #56March 13, 2006, 04:32:29 pm

RabbitJockey

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« Reply #56 on: March 13, 2006, 04:32:29 pm »
good info, would the golf gti tach that regcheeseman be the same as a cabriolet tach?  cause i could get a cabriolet tach pretty easily, and it slip right into my car since jettas and cabbys had the same dash.
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Reply #57March 13, 2006, 09:46:58 pm

RabbitGTDguy

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« Reply #57 on: March 13, 2006, 09:46:58 pm »
Quote from: "regcheeseman"
Read the 4 crawler link and a lot of it seems hypothetical. Maybe his 4 pulse application worked but every 4 cylinder single coil motor I've ever worked on had 2 pulses per rev...

Oh no. I've just sussed it... probably should have read the text it may have been explained.

He was taking a signal from the injection pump and the injection pump runs at half engine speed hence doubling the pulses!

Let me know the TDI setup.

Johnny,

If you can photograph the other side of the board I may be able to help but I doubt it very much - it has the wrong chip.  :(


As and you shall receive. I have not had alot of luck with finding info on the sensor specifically...however, I do have pics.

1z TDI crank sensor



crank "pickup" wheel  You can see the pickup wheel on the left side of the crank against the rear seal housing as well as the "cut" in it. There are 4 of these...


I know its not much info... but I'm working on getting more :)

Joe
1979 Rabbit mTDI crazy $*(\%& bunny...
1972 VW Westfalia
2009 VW Tiguan SE 2.0T (Wife's car)
2001 Audi TT 225 Quattro Roadster (something newer :) )

Reply #58March 14, 2006, 07:01:58 am

johnny

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« Reply #58 on: March 14, 2006, 07:01:58 am »
I will try to disassemble it further so you can see the other side of the printing circuit and take some pics.
What you see on the pic is the whole tach assembly, you can click it right in your cluster. On the tach you have four pins (+,-,ZA and ZE), I don't know where ZA and ZE stand for. Maybe someone can help me out ?

@ fastmobile
Is this maybe the first european tach you see ?

Reply #59March 14, 2006, 09:22:22 pm

biobill

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PCB from 93 Cabriolet with MotoMeter tach
« Reply #59 on: March 14, 2006, 09:22:22 pm »
OK, I've dug in and found the board for my tach!
Hopefully not too different, despite the unique chip - TI 9236XRX and the little thing below R3 & R2 - I believe the board says ZD1 (obscured) and BZX (very small) is written on the component. Here are the pictures:


from my poor decoding skills, I'm guessing
R1 = 23k
R2 = 220
R3 = 2.2k
R4 ? 210? help!
R5 = 82
R6 + 100
R7 = 25k
R8 = 22k variable

C1 = 2200
C2 = 0.22 uF
C3 = 22M
C4 ? 220T

I've tried to sketch out the schematic and it seems to share many characteristics of schematics already presented by regcheeseman. Pardon the low tech sketch.


Have I got a chance??  Thanks in advance for any/all help, and let me know if you need more info to decipher!
'93 Cabriolet Turbo Diesel - in process!
'96 Passat TDI Wagon - 237k miles
'05 Jetta TDI Wagon - 36k miles (wifes car)