1jz coils, which side is negative?

[lojik]

I want to use the coils to drive my tacho, I have the circuit using a few diodes to run the tacho from the -ve side of the coils.
Each coilpack has a black/orange wire and a coloured wire. The coloured wires all run into the ignitor, are the coloured wires -ve?
I'm assuming the black/orange wires are a common +ve for all coils.

[wilbo666]

I think you are going about wiring your tacho the wrong way!

There is a tacho output from the ignitor that is a 12V square wave. If need be you can convert this 12V output to a simulated coil with a very simple circuit. Have a search for the circuit!

That should make it much easier to get your tacho working!

Cheers
Wilbo

[lojik]

Cheers wilbo.
I already have a tacho booster, which Im guessing is similar to the circuit you are referring to. The tacho drops out above 3k, but works fine below. The tacho booster is being driven by a 12v square wave from an aftermarket ecu.
The only reference I found to a similar problem lead me to the diode circuit.
The tacho is the stock digi dash one in an ma61.

[mrshin]

MA61 tacho's are a bit of a mongrel... but by pulling the cluster apart and have a bit of a fiddle, it is possible to make them work straight off the igniter. I'm not sure exactly what is done, but I know it can be done and don't think it'd be too hard to work out if you're slightly handy with electronics.

[wilbo666]

I'd suggest building the circuit that is around. Perhaps the tacho booster that you have isn't up to the task? The circuit costs almost nothing to build so you don't have much to loose really (perhaps a bit of time)

Cheers
Wilbo

[The Witzl]

Contact Jason Purcell (aka "JP") on these forums and Twincam.org forums..... he modified his tacho on his GX81 to accept the ignitor's tacho output on his 1JZ-GTE conversion.

I think his website, www.rollamods.com even has a tech article on this mod somewhere
If i find it, i'll put it in the FAQ

[The Witzl]

haha!!

I have links, courtesty of Mr JP himself

http://www.masa-ya.jp/bike/jzx70g/tacho.html

http://www.rollamods.com/tech/ae86gzetacho.pdf

you should be able to use the first link as a guide to modifying the MA61 tacho

[lojik]

ta Witzl,
So going from those links I need to change a few components on the tacho board, and then the tacho will be correctly driven from a 12V square wave, which I can get from the ignition module or the ecu?
Are the images in the first link are from the ma61 tach or similar?

[wilbo666]

ta Witzl,
So going from those links I need to change a few components on the tacho board, and then the tacho will be correctly driven from a 12V square wave, which I can get from the ignition module or the ecu?
Are the images in the first link are from the ma61 tach or similar?

Looks nothing like a MA61 dash. Good luck tracing it in a MA61. I had a quick look at it and couldn't work it out easily Not to say that you can't.

Cheers
Wilbo

[lojik]

In that case, any hints on where I can get that circuit you were speaking of Wilbo?

[wilbo666]

http://www.toymods.net/forums/showth...=tacho+booster



Serch and ye shal find

Cheers
Wilbo

[lojik]

Ta,
Reading through that thread, I came across this post:
http://www.toymods.net/forums/showpo...7&postcount=25
Which I will steal the image from:

The image above is the two coil version of the three coil circuit I was originally wanting to use.... I've already bought all 70cents worth of the diodes/resistors
If that circuit is suitable I'll just use that, in which case, I still need to know which wires from the igniter I can use as -ve's from the coil.
My understanding is that the haltech diode circuit is just combining the three coil inputs into a single output for the tacho. Whereas the other circuit takes a 5 or 12v pwm and converts it into a coil type output for the tacho.

[ViPeR_NiPPleX]

http://www.toymods.net/forums/showth...=tacho+booster



Serch and ye shal find

Cheers
Wilbo

I really want to redraw this circuit, values aren't accurate. However, simple parts list...

1N4007
12v relay coil (approx 300ohm impedence... gut the thing unless you love clicking noises)
BC546 small signal transistor
2k2 / 2k7 / 3k3 1/4w resistor

there you go. get a prototyping board, tag strip, or even just solder the legs together and tape it up

[wilbo666]

You can do what you desire, your method seems to me to be a little harder, and more invasive (connecting to the coil wires), but upto you

Cheers
Wilbo

[lojik]

Yeah I suppose it comes down to that really doesnt it, I just thought I'd avoid the tacho booster as the one I have doesnt work properly.
I'll see how I go.
Thanks everyone for your input.
I'll throw the +rep around.