GreenMachine

buying my first new standalone ecu, there is a great local deal on an new assembled ms3x, im having my harnesses assembled by somebody and I'm wondering if the ECU board needs to be modified or changed to run my rotary

thank you

ACR_RX-7

iTrader: (1)

The short answer is yes. There are jumpers and pots that need to be set.

How To Megasquirt Your 2nd Gen RX-7: Modding And Setting Up Megasquirt MS3X

GreenMachine

Ok thank you, that page is contradictory though, the first paragraph says no changes need to be made. Then it describes what about it you have to change?

Aaron Cake

iTrader: (1)

There are no hardware changes needed if you are using the V3.57 board and the MS3X expander board. Generally this is the configuration of assembled MS3Xs as sold. All you need to do with the ECU is set the correct jumpers and turn all the pots fully counterclockwise.

Your harness will need to be modified for shielded cable if not already supplied that way, as described in the link.

GreenMachine

Yes the ECU was originally purchased from diy with the 3.57, I have never made any changes what so ever to a board like that what are some precautions and margin of error?

Before you say maybe the diy aspect of megasquirt isn't for me, I'm determined to save the money and utilize the features available at such a price point compared to say haltech/aem, plus I find the tuning software fun and easy haha

Aaron Cake

iTrader: (1)

Setting the jumpers on the boards and turning the pots is a pretty easy operation. Just open up the case and follow the instructions on the page in my writeup linked above. Only thing is that the end stop on the pots isn't obvious so go slowly and concentrate on listening for the faint click and feeling the faint stop.

Tap something grounded (like a metal outlet cover) before handling the boards, just as a precaution. I've personally never found static to be an issue.

Make sure the person assembling the harness is aware of the possible need to add shielded cable.