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Megasquirt and Koso Digital Dash
ChrisLeary - 19/8/13 at 09:25 PM

Evening all,

I'm currently wiring the engine for Megasquirt. It's a 2l zetec on gsxr TB's. The wiring for MS is done, but I'm going to be using a Koso RX1N digital dash.

Can anyone tell me where I can connect to get a reading for RPM? I have the choice of two cables that came with the installation kit, one (I think) connects to the trigger wheel and crank sensor? The other seems to be connected to the ECU and to the HT lead.

Hopefully someone can help, I'm on the verge of a first start!

Best regards,

Chris

dave_424 - 19/8/13 at 09:47 PM

Not sure what kind of signal your dash wants, I know that you can use one of the megasquirt IAC wires to give a pulsed 12v signal which is what I needed for my ZX9 clocks, there are also other outputs that will do pulsed 5v I think.

If your digital dash connects to the crank trigger, then there must be a way for you to tell the dash how many teeth you have on your crank wheel so that it can calculate your RPM

From this manual http://www.kosonorthamerica.com/instructions/BA011W02.pdf it looks like you can do it 3 ways, connect into your crank sensor, connect into the + side of your coil, or wrap around your HT lead.

I would either connect into your crank sensor wire (be careful as it may introduce noise into the crank signal that megasquirt sees)

Or it looks like you could either wire it up in the B configuration getting a signal from your positive wire on your coil, or if you aren't using an idle air control valve, you can get megasquirt to send the dash a pulsed 12V signal.

Dave

shaunod - 12/9/13 at 09:45 AM

If you have a tacho out from the MS then that should provide a low amplitude 5v pulse. This may be enough to drive the clocks but if it isn't look for a TachFix on ebay .. that will convert the 5v pulse into a 12V square wave (similar to a negative coil pulse) that should work for most clocks.

baz-R - 6/10/13 at 02:28 PM

with any luck your dash will be able to be set to work on 1 rev 1 pulse if so conect the tach cable to only 1 of the coil triggers from the ecu

wombat - 27/3/14 at 12:35 PM

Chris,
What did you do to solve this ?

ChrisLeary - 27/3/14 at 01:06 PM

quote:
Originally posted by wombat
Chris,
What did you do to solve this ?


Wombat, I spliced into the 12v feed for the coil and have a stable reading on the koso dash now. The car isn't back on the road, but it's been running and when revving the engine it matches the MS reading on the laptop.

ATB,

Chris