Wow, that's cool man, gonna do this to mine for sure!
Hi everyone. If you are like me, and you run coil on plug ignition or coilpacks, you probably have connected the tacho wire and noticed that the tacho doesnt function. Mine would do the odd jump and show different data if you turned the lights on or went into reverse, etc. It never actually worked in the 3 years Ive had a 20v ae71 on the road.
I decided yesterday enough was enough so I found the info for the GZE tacho mod into ae86. I then did a few experiments with my tacho to get it working as it should.
The ae71 has a different Tacho circuit board to any other corolla. It has a variable resistor from standard to adjust the tacho readout which is something that nobody has noticed on other corollas from what I can tell. Its quite cool really.
The process for adapting your tacho so it will function correctly is quite simple and outlined in the below before and after photos.
You will need one 15kohm resistor and and capacitor. If you want a greater range of adjustment you can go to a variable resistor with a greater range of adjustment.
Yes a couple of others have done this and reported it worked great for them to, so go for it eh. Its great to have a little data.
thanks heaps matt, great article
~KEEP DRIFTING FUN~
Could it work for a Mr2 tacho??
would this work for adm ae86 as well?
any info for the digi dash?
Nope, never played with one. Not to say it cant be done, but I would need to look at one and fuck with it, Might be unsuccessful. Just open it up and if it has a similar circuit board to the analogue ones then you could possibly work it out.
Very Cool Matt!
Wish i was a little bit more proficient on the electrical side of things.. will keep this bookmarked for when my motor goes in.
Haha, Im not doing this according to electrical theory. I did my mod based on the ae86 mod info that I found. I related it to the circuitry architecture in the 71 tacho, and worked out what to do by comparing them and the resistor values. I followed and described the circuits and saw how they differed, then was able to select a few values based on the ae86 mod, and it worked. Not rocket science, and from an electrical theory point of view, I cant explain myself, but there really is no substitute for just giving stuff a go. Considering how simple it really is, its kinda shame on all the electrical genius types that assured me its possible and failed at it without ever having actually worked out how to do it. I cannot see why a decent auto wiring guru would let a car leave his sight with this unfinished.