MX83 tacho modification

[mr1jz]

So i have a series 2 mx83 with a 1j and a link ecu (Vipec).
I've searched and i know i can do a tacho booster and i know ray hall has a diagram for a tacho booster on the Vipec site but i want to actually modify the factory tacho to accept the signal sent from the link. I know this can be done as i have the PDF for the AE86 tacho conversion but the problem is i am not much of a electronics wizz.

So i am after someone who is willing to shed some light on the situation. I can do the mods myself but i just need a bit of direction as to what needs to be done.

I've added all the pics i can get to make it easy.

Front of tacho board


Back of tacho board


I have also added the AE86 tacho mod as a pdf. This was hard enough to find on it's own.

Cheers in advance.

[Maverick]

This ought to make it better:

[mr1jz]

Title now fixed. Cheers

[Cuzzo]

Want to update the thread with what fixed it?

[mr1jz]

Sorry, Meant that the title had been updated.

[Cuzzo]

Ahh ok,

Any idea what type of signal the link is sending out?

[rshuwy]

gaugeworks on port rd in adelaide do this modification, i had it done to my dash.

give them a ring maybe?

[mr1jz]

I don't really want to be sending the dash away. I know i can do it myself, i just need an electronics guru for a bit of advice.

This is from LINK.

An auxiliary output configured as 'Tacho' produces a 0-12V pulse to drive a low-level tachometer. There will be one output pulse for each time a cylinder reaches TDC. Connect an Auxiliary Output directly to a low-level tachometer.

G4 ECUs will NOT drive a high-level tachometer. High-level tachometers must be triggered by a coil’s negative terminal. Using a high-level tachometer on a multi-coil engine presents some problems, as each coil is not firing as often as a distributor engine’s coil would. In this case the preferred solution is to modify the high-level tachometer to accept a low-level signal.

[JP]

in Wilbo's thread here: http://www.toymods.org.au/forums/sho....php?p=1165293 the resistor on the signal line is bypassed/lowered. I can't quite make out the pcb tracks in your pic so I'll pull apart my spare cluster to see if it has a similar resistor inline. My car's not running yet so wont be able to test it myself for a couple of weeks.

I put together that PDF in the original post when I needed to make my AE71 tach work with a 4agze ECU, I did a similar thing to my GX70 tach to make it work with a vvti 1JZ ecu also.

[takai]

Works also for the RA65 tacho and a 2JZGE

[mr1jz]

Cheers JP. I thought i remembered something about you and that PDF.

[JP]

I need to trace out the MX83 board properly and figure out what the vertical black 750611-650 component does, I suspect it might be similar to what the resistors and caps do on the input of the older tach driver boards.

Wilbo did an overlay of some new pics I took to make it easier to view what-goes-where, and for reference here's a schematic from one of the guys in japan who traced out a GX70G tach driver board:
http://masa-ya.jp/index.php?plugin=r...ho.png&thumb=1

Overlay: http://www.purcellperformance.com/uploads/overlay.jpg

[mr1jz]

Cheers JP. You are a godsend. Are you going to be doing the same with your's?

[JP]

yep, I hate external boosters.

[mr1jz]

Yeah i'm the same. I wan't to keep stuff to a minimum. I hate seeing cars full of crap they don't need. I have been watching your build and i must say, i'm very impressed with your work. Thing is though, it makes me feel bad that i have not updated mine.