dpuma8 Posted July 16, 2014 Share Posted July 16, 2014 I am ready to install Megasquirt but I was wondering what happens with the old wiring. Did you rewire the whole car or am I just keeping everything the same but just unplugging the original Ecu? Quote Link to comment Share on other sites More sharing options...
dexter72 Posted July 16, 2014 Share Posted July 16, 2014 You will have to decide what to do with the original wiring, depending on what your going to do with the car. Buy the megasquirt wiring harness, each wire is stamped for where it goes. Makes install easier. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted July 16, 2014 Share Posted July 16, 2014 Its an involved process either way. Depening on which engine it is will depend on if you leave out the knock sensor or whatever. The real question is what do you need to hook up, not what gets left out. Look at the diagram. Everh sensor needs to get hooked up on that diagram, except the O2. But a wideband is a must for tuning. Its a whole new ECU, so dont think that if a sensor is on the motor, it needsto be hooked up. Definitely chuck the old MAF in the garbage and either get a newer on like I did (Z32) or go speed density, aka MAP sensor. Dont think that a MAF is a hinderence to tuning, those of us who switched to MAF on the MS love it. Quote Link to comment Share on other sites More sharing options...
dpuma8 Posted July 16, 2014 Author Share Posted July 16, 2014 I have everything I need for the Megasquirt side of things which means I have all the sensors, relay board, and labeled wires. I was just wondering about the stock wiring. So just unplug the old ecu and off I go installing Megasquirt? Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted July 16, 2014 Share Posted July 16, 2014 What worked for me on the Z31s I've megasquirted was reusing some of the stock wiring. This took some time and planning but required less rewiring. On my S30 I opted to use one of the fancy wiring harnesses. Totally worth it, especially since the S30 wiring was really archaic, and a lot of wires were the same color. Also, I didn't have to assemble that damned DB37 which in itself was worth the price. So, go with rewiring it with the DIY harness. Keep in mind you'll still have to locate the stock ECU power, ground, CAS, etc. wires. You may also have to rewire a relay or two, IIRC. So first wire up what you need, get it running, then you can remove unneeded stuff later. Quote Link to comment Share on other sites More sharing options...
winstonusmc Posted July 16, 2014 Share Posted July 16, 2014 On my S30, the power is wired straight to the battery and the Sign on signal comes from the fuel pump power wire. I built my own relay board, but the concept is still the same. With the relay board and the DIY harness, all you need in wiring is there. Just remove all of the upper harness and keep the lower harness for the alternator and starter. Run the power wire for the relay board to the starter and find an ign on signal to pull from for the relays. The old wiring can be removed without cutting anything, I would just get it out of the way. Quote Link to comment Share on other sites More sharing options...
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