hooking up outputs with megasquirt-I got a question-

[big-phil]

for example, for hooking up a tacho, I kinda understand the wiring, and resistors and such. BUT see where the wire goes to the tacho? how does that wire get from the inside of the ECU to my tach? Do I solder it to one of the pins going to the cable that goes to my relay board, and then from the relay board to the tach. Also for the same for fan control and such.

[z-ya]

You need to use one of the spare pins in the DB37 connector. Then you need to add another wire to your DB37 cable. If you are using a relay board, the spares are available on the terminal block, otherwise you just need to run it directly to your tach. You need a 73' or new tach to use this output BTW.

[big-phil]

OK thanks! mine is a 78 so it should work.

[Matt Cramer]

You can use one of the IAC jumpers on a V3.0 board (on a V2.2, it's X11 through X14 instead). The IAC wires are in a normal relay cable, but not used for idle control on a 280ZX.

[Raami]

You need to use one of the spare pins in the DB37 connector. Then you need to add another wire to your DB37 cable. If you are using a relay board, the spares are available on the terminal block, otherwise you just need to run it directly to your tach. You need a 73' or new tach to use this output BTW.

 

 

How can I use my original tach with my MS?

My car is 240z -72 and I have understand that I can't use that diagram in big-phil's post.

My MS already has that wiring but the stock tach doesn't work with it.

I have searched but haven't find answer.

[big-phil]

How can I use my original tach with my MS?

My car is 240z -72 and I have understand that I can't use that diagram in big-phil's post.

My MS already has that wiring but the stock tach doesn't work with it.

I have searched but haven't find answer.

Thats the magic question, my tach still don't work.

[Raami]

I really would like to leave that stock tach.

I will try some other diagrams and I will let you know if I can make it work.

[Raami]

Have anyone tried this?

[z-ya]

Your 72' tach is a current sensing tach. MS is not compatible with it. as per my original post, you can get a 73 or later S30 tach, and use the tacho output from the MS.

 

Are you using a single coil? If you power it from the factory black/white wire, your 72 tach should work (as long as you are not using an MSD).

[Raami]

I'm using wasted spark coil pack so I don't have single coil.

I made 6-1 triggerwheel so I don't have distributor anymore.

So I just have to find -73 or later tach.

[Noddle]

I'm using wasted spark coil pack so I don't have single coil.

I made 6-1 triggerwheel so I don't have distributor anymore.

So I just have to find -73 or later tach.

 

 

Would this work ?

 

http://www.gweeds.net/carpage2/RevCounterCircuit.pdf

 

Nigel

[Raami]

Would this work ?

 

http://www.gweeds.net/carpage2/RevCounterCircuit.pdf

 

Nigel

 

 

I have to find out could this be used.

[Noddle]

I have to find out could this be used.

 

This might work also,

 

http://www.megamanual.com/ms2/EDIS.htm

 

look at the info at the bottom of the page.

 

I spotted this when I was researching MS with EDIS

 

Nigel

[mobythevan]

I am using the tach circuit in the first post to drive the tach in my 86 rx7. I know that doesn't help much for the datsun tach, but one thing to note is that I don't quite get the correct reading. At 2500rpm in megatune my tach reads like 2800rpm. I think it is noise so I am going to try adding a capacitor to the line. Just in case you guys see results like this.

[z-ya]

You are missing my point.

 

The 70-72 tachs are CURRENT sensing, not VOLTAGE. I am not going to educate you here on the difference between current and voltage. You will need to do that on your own.

 

All modern tachs are VOLTAGE sensing. To build a circuit that will properly OR (logical) CURRENT from three different coils would be very difficult. An easy thing to try is to power all three of the coils from the black/white coil wire. This will provide power to all three coils THROUGH the wire loop on the back of the 72' tach. So each time a coil fires, a current pulse will flow through the wire loop on the back of the tach, causing the needle to deflect.

 

If this doesn't work, get 73-78 tach. Then you can either use the tacho output or the circuit below if you are using all of the outputs from MS:

 

 

Pete

[mobythevan]

You are missing my point.

 

huh?

[z or bust]

HAHAHAHA dont worry Moby i'm lost too.

[Raami]

You are missing my point.

 

The 70-72 tachs are CURRENT sensing, not VOLTAGE. I am not going to educate you here on the difference between current and voltage. You will need to do that on your own.

 

All modern tachs are VOLTAGE sensing. To build a circuit that will properly OR (logical) CURRENT from three different coils would be very difficult. An easy thing to try is to power all three of the coils from the black/white coil wire. This will provide power to all three coils THROUGH the wire loop on the back of the 72' tach. So each time a coil fires, a current pulse will flow through the wire loop on the back of the tach, causing the needle to deflect.

 

If this doesn't work, get 73-78 tach. Then you can either use the tacho output or the circuit below if you are using all of the outputs from MS:

 

 

Pete

 

 

I understand that.

That might work what you said and it really is easy to try. I will let you know if it works.

I have opened that type of tach and I know how it works.

[z-ya]

huh?

 

HAHAHAHA dont worry Moby i'm lost too.

 

Are you guys just yankin' my chain or what?

[mobythevan]

Are you guys just yankin' my chain or what?

 

just razzin you, I think I read the posts out of order