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Distributor to Coil Pack Tachometer Conversion
Topic Started: Aug 13 2014, 02:41 PM (2,584 Views)
aaronvincent
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Mr Mojo Risin'

If you're like me and own a 1998+ Metro you will find that it uses coil packs instead of a distributor. If you buy an instrument cluster with a tachometer it has to be one that works with the G13BB engine (made on or after 1998). THIS GUIDE IS TO HELP YOU CONVERT 1995-1997 TACHOMETER CLUSTERS TO WORK IN A 98+ MODEL. I bought a 1997 instrument cluster that uses the pulse signals sent via the distributor to display engine RPM. My engine with coil packs has no clue what to do with those signals making the tachometer non-functional. If you want your tachometer to be functional you must follow the steps below. Please be aware this isn't the easiest task and if you choose to attempt it I am not responsible for any damage that may occur. Ready? Here we go

STEP 1: Flip the cluster over after removing the plastic face-plate and locate the three screws holding in the tachometer to your left. Remove all three (they are all phillips heads).

Posted Image

Here it is removed with the stuff I'm using for the conversion. You will need a soldering iron, 1 Silicon Diode (just for the long wire bit), and some 60/40 ROSIN-CORE solder.

Posted Image

STEP 2: You should now have the tachometer in front of you. Take a look at the underside of the circuit board and locate the transistor circled in red.

Posted Image

STEP 3: Remove said transistor because it controls the signal sent by the distributor. We don't need that, we have coil packs and we're just going to jumper the connection to loop it out of the system.

Posted Image

STEP 4: Buy a cheapy $1 diode from radio shack and use the metal wire bit to jumper the connection. You will NEED a soldering iron for this to remove the remnants of the resistor and solder the jumper in place.

Posted Image

Here it is with the jumper soldered in place of the transistor. Now when the signal comes into the cluster it will simply skip this part and go directly to the tachometer. I'm not sure of the logistics entirely but I know that for some reason it works. You now have a working cluster for a 1998+ model with coil packs. Put it back together and enjoy. BE AWARE THAT IF YOU DECIDED TO REMOVE THE NEEDLE TO GET TO IT YOU'LL HAVE TO INSTALL THE CLUSTER WITHOUT THE CLEAR BIT AND PUT THE KEY TO THE "RUN POSITION". Then you may put it back together or it will not calibrate correctly.

Posted Image

And that is how you get an instrument cluster with a tachometer from a 1995-1997 4 cylinder engine to work on a 1998+ metro with a 4 cylinder engine. It's difficult but it does the job :rocker
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Mythstae
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:holycrap :omg
Is that seriously all it took to make it work?!
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aaronvincent
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Mr Mojo Risin'

Yep. Big fat thanks to member geopat of both Teamswift and GMF for pointing me in the right direction. I would never have guessed it would be such a simple little thing to make it work. Also big thanks to Mike Cove of 3tech for helping me get in contact with geopat to figure all this mess out. Thanks guys! It's installed and working so hopefully I can enjoy this cluster forever now! :rocker

Here is the original thread over on Teamswift from 2007 where geopat explains how it all works.

http://www.teamswift.net/viewtopic.php?f=30&t=32836&start=25
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Woodie
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Nice job and nice writeup aaronvincent. Same on the odometer rollback, these should be stickied. You keep wobbling back and forth between resistor and transistor above, it's a resistor.

I knew someone had posted the fix for this, just didn't know where and haven't had the time to find it. Glad you were able to.
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nathan298
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Geo Resurrector

:thumb That's awesome! Never thought it would've been that simple to convert. Glad you got it to work.
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Stiffchezze
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Sir Metrologist

Can confirm, 100% works! (even with a 1.6L B-) )

Great guide, almost lost to photbucket. :rasp

aaronvincent, I miss you man. :(

(Edited to save pics on the Forum)

Also, wear gloves to prevent fingerprints. It will drive you insane if you see one after you put it back together. :banghead

aaronvincent
Aug 13 2014, 02:41 PM
If you're like me and own a 1998+ Metro you will find that it uses coil packs instead of a distributor. If you buy an instrument cluster with a tachometer it has to be one that works with the G13BB engine (made on or after 1998). THIS GUIDE IS TO HELP YOU CONVERT 1995-1997 TACHOMETER CLUSTERS TO WORK IN A 98+ MODEL. I bought a 1997 instrument cluster that uses the pulse signals sent via the distributor to display engine RPM. My engine with coil packs has no clue what to do with those signals making the tachometer non-functional. If you want your tachometer to be functional you must follow the steps below. Please be aware this isn't the easiest task and if you choose to attempt it I am not responsible for any damage that may occur. Ready? Here we go

STEP 1: Flip the cluster over after removing the plastic face-plate and locate the three screws holding in the tachometer to your left. Remove all three (they are all phillips heads).

Posted Image

Here it is removed with the stuff I'm using for the conversion. You will need a soldering iron, 1 Silicon Diode (just for the long wire bit), and some 60/40 ROSIN-CORE solder.

Posted Image

STEP 2: You should now have the tachometer in front of you. Take a look at the underside of the circuit board and locate the resistor circled in red.

Posted Image

STEP 3: Remove said resistor because it controls the signal sent by the distributor. We don't need that, we have coil packs and we're just going to jumper the connection to loop it out of the system.

Posted Image

STEP 4: Buy a cheapy $1 diode from radio shack and use the metal wire bit to jumper the connection. You will NEED a soldering iron for this to remove the remnants of the resistor and solder the jumper in place.

Posted Image

Here it is with the jumper soldered in place of the transistor. Now when the signal comes into the cluster it will simply skip this part and go directly to the tachometer. I'm not sure of the logistics entirely but I know that for some reason it works. You now have a working cluster for a 1998+ model with coil packs. Put it back together and enjoy. BE AWARE THAT IF YOU DECIDED TO REMOVE THE NEEDLE TO GET TO IT YOU'LL HAVE TO INSTALL THE CLUSTER WITHOUT THE CLEAR BIT AND PUT THE KEY TO THE "RUN POSITION". Then you may put it back together or it will not calibrate correctly.

Posted Image

And that is how you get an instrument cluster with a tachometer from a 1995-1997 4 cylinder engine to work on a 1998+ metro with a 4 cylinder engine. It's difficult but it does the job :rocker


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Woodie
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Wish I had known this 15 years ago. I put like 5 different clusters in trying to find one that worked. Finally cut one to bits and mounted an aftermarket tach in there.

Is it safe to assume that he means resistor when he says transistor?
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Stiffchezze
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Sir Metrologist

Woodie
Oct 19 2017, 04:45 AM
Is it safe to assume that he means resistor when he says transistor?


Yep. B-) Edited in the one I quoted.
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WiscoMetro
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Seeking the Science of MPG

aaronvincent
 
BE AWARE THAT IF YOU DECIDED TO REMOVE THE NEEDLE TO GET TO IT YOU'LL HAVE TO INSTALL THE CLUSTER WITHOUT THE CLEAR BIT AND PUT THE KEY TO THE "RUN POSITION". Then you may put it back together or it will not calibrate correctly.

I did this when I recently did my 4 to 3 cylinder tach conversion. I think a better plan would be to use a Scanguage or similar to see the rpm and put the needle on then at that rpm. And more importantly confirm it is correct before putting the clear bit back on...

Just turning the key to on and pushing the needle on at 0 led mine to be a constant 300 rpm above. But until I have a better reason to I'm not taking the cluster back out... :x
Edited by WiscoMetro, Oct 19 2017, 11:58 PM.
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