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The Great Kruso
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This all started a few years ago when I was doing retro's on the clusters. I would go to put the faces back on and attempt to calibrate them. I thought I was getting tachs that were broken cause I couldn't calibrate them. So on my dollar, I replaced them. Fast forward 2 years later, I dug these old tachs out and ran them with a Dakota Digital converter. All 3 work perfectly as NA tachs. So what I thought were bad tachs ended up being (probably) a NA-T conversion car and they never told me. So 3 people got a sweet deal!

But my assumption was these were all TT harnesses, but now I am not sure. As far as converting a NA tach to work on a TT car, I have yet to find away to do this. Other than buying a Dakota Digital converter for $80, then your golden. Toyota has totally different guts between these 2 tachs as I have studied them enough that adding/deleting a resistor wouldn't do squat for converting.
Sorry for late response, I've been inundated with my schedule and only come to SF to get away from it. Here are bits of known configurations that work a hundred percent. This is all first hand verified by me personally...
*TT tach in a NA-T car with USDM TT harness and TT ECU will work without any mods.

*NA tach, USDM harness and ECU with a jumped resistor will work, just like Kirk pointed out towards the beginning of the thread.

*NA-T car with JDM Aristo or JDM MKIV harness retrofitted to it will NOT work unless you bring in the tach signal from the ignitor plug into the chasis and plug it into the chasis harness (70% sure that was with a resistor bypass implemented aswell but try it both ways as I can't remember exactly what I did as it was too long ago). This one was the most time consuming find because there is a ton of incorrect information on this board primarily led by all hearsay which derails progress. This last configuration is what I'm currently running on my MKIV.
 

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Raising the BAR
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I'm 100% sure it is with the resistor bypassed and the wire being run from the igniter to the tach.
 

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The Great Kruso
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I'm 100% sure it is with the resistor bypassed and the wire being run from the igniter to the tach.
I wanted it to look stock so I traced the wire to the plug near the ECU DJ, not to the tach directly. Taking it directly from the ignitor to the cluster would look "tacky" (pun intended).
 

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Raising the BAR
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I was just saying the resistor jump is 100% with that setup. I know you can just run the igniter wire the way you mentioned.
 

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Ok so I have two dead tachometers.
1. A JDM TT using AEM V1. The original jdm TT Tach wont work.
Setup:
1993 JDM 2JZ-GTE automatic
2JZ-GTE Engine
1993 JDM 2JZ-GTE Engine Harness
AEM V1 EMS (GE vesion running wated spark of course)

2. JDM GE with JDM TT ecu mod. Have not tried to get it working as yet. Any suggestions.
 

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936 Posts
Ok so I have two dead tachometers.
1. A JDM TT using AEM V1 ge version. The original jdm TT Tach wont work.
2. JDM GE with JDM TT ecu mod. Have not tried to get it working as yet. Any suggestions.
Ok I think just bridging the JDM GE tach should work as it did for MR Ree NZ, he too has a JDM GE with JDM TT ecu mod. That should solve dead tach #2. Will test it befor next weekend and report back.


The TRD tacho is working now, as we just unsoldered the resistor, and replaced it with a wire. Im not sure if it is perfectly calibrated but it seems to be as I took the car up to 6800rpm and the emanage was saying the same, so all seems good there.
Take out the tach and look at the circuit board. See the 33K ? resistor on the top right hand corner. Jumper the resistor with a wire. Put it all back together. Hook up the wire from the TT Igniter A1 terminal (ext) to the blk/wht wire on the Diag connector (tach) and your good to go.
this may come in handy: http://www.toymods.org.au/forums/showthread.php?t=46365&p=1164226&viewfull=1#post1164226
 

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Ok so I have two dead tachometers.
1. A JDM TT using AEM V1. The original jdm TT Tach wont work.
Setup:
1993 JDM 2JZ-GTE automatic
2JZ-GTE Engine
1993 JDM 2JZ-GTE Engine Harness
AEM V1 EMS (GE vesion running wated spark of course)

2. JDM GE with JDM TT ecu mod. Have not tried to get it working as yet. Any suggestions.
Ok, I got both tachs working.

1. For the JDM 2JZ-GTE with the AEM and HKS twin Power, all I had to do was run a wire from the A1 pinout of the GTE igniter to the #29 pin on the big orange body plug harness next to the ECU in the passenger foot-well. http://i224.photobucket.com/albums/dd108/wilbo666/II1.png
This being a 2JZ-GTE car originally, the tach already had the correct resistor.



2. JDM GE with JDM TT ecu mod, all I had to do was jump the GE tach resister. I used a 10k resister instead of a jumper wire.

Thx Guys.
 

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Yeah that fix will work for you, I looked into doing this when I was considering an aristo swap. No reason to waste money on a TT tach unless your'e going auto to manual or vice versa or just want a sexy TRD tach
 

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HMOOB VWJ NYOB MINNESOTA
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1,352 Posts
Here is mine:

USDM NA 5spd to USDM TT 6sp/harness/


Stop by Radio shack and pick up some 22k with 1/2w.


Measure the length:


Took out stock NA 43k Resistor and solder in the 22k:


Test it and looks to match up pretty good, low and high RPM:
 

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HMOOB VWJ NYOB MINNESOTA
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1,352 Posts
Didn't do anything, just remove the NA Resistor and solder in the 22 resister. I use the OEM USDM 6sp harness.
 

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Sorry to bump this up guys but though it be better than starting a new thread

I did a jdm aristo engine in my 93 na 5 speed.im using a obd1 6 speed harness, aristo ignitor, with a aem v1.i swapped tach out for a 6 speed one and when i turn key tach jumps to 2k and will read rpm signal from there..im kinda stummped on this issue cause i thought just swapping to a 6 speed tach would take out all the headache..some help on where to go with this issue would be great
 

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Stock Twins King
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4,396 Posts
Sorry to bump this up guys but though it be better than starting a new thread

I did a jdm aristo engine in my 93 na 5 speed.im using a obd1 6 speed harness, aristo ignitor, with a aem v1.i swapped tach out for a 6 speed one and when i turn key tach jumps to 2k and will read rpm signal from there..im kinda stumped on this issue cause i thought just swapping to a 6 speed tach would take out all the headache..some help on where to go with this issue would be great
Odd..for the hundreds of tachs I have dealt with, what your saying is exactly how a NA tach acts up in a TT car. Your sure you got a TT tach?
An NA car gets the tach signal direct from the igniter. A TT car gets its tach signal from the main ECU and not from the igniter. I would make sure that the AEM is configured properly for the tach out put signal to the combo meter A16 is the ECU tach output. I would check for continuity from A16 to the back of the tach "IG-" screw.
 

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Odd..for the hundreds of tachs I have dealt with, what your saying is exactly how a NA tach acts up in a TT car. Your sure you got a TT tach?
An NA car gets the tach signal direct from the igniter. A TT car gets its tach signal from the main ECU and not from the igniter. I would make sure that the AEM is configured properly for the tach out put signal to the combo meter A16 is the ECU tach output. I would check for continuity from A16 to the back of the tach "IG-" screw.
I got the tach off a forum member so idk 100 percent sure it was correct..i havent yet slapped back in the na tach to see how it reacts.i also havent gotten into the aem yet to see if there is a adjustment in the ecu for this..im new at all this and basicaly have relied on forum to aid me in this swap..maybe im missing a step or something..do you think my issue could be in the v1 not being set up correctly?
 
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