cholag Posted August 4, 2008 Share Posted August 4, 2008 I was thinking of posting this in the electrical forum but since I am using an ms2 I thought this one would be more appropriate. But my questions are how would I wire up lights, dash lights, radio, alternator and things like that, I am thinking that I need to take out my entire wiring harness and make a new. I would have one harness for my engine stuff that will hook up into my relay board and a second one going to all my other stuff, but how would I hook it all up and where? Would I just hook everything up to my battery and then put resisters where they need to go? I think I am making this a lot harder then it should be but I have been wrenching my mind around this situation of mine for some time now. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted August 4, 2008 Share Posted August 4, 2008 The Megasquirt doesn't really affect the rest of the wiring, only the wiring for its own inputs and outputs. The relay board just needs power, ground, and a switched 12 volt source to turn it on - these are the only connections with the non-EFI wiring. The rest of it doesn't connect to the MS at all. Quote Link to comment Share on other sites More sharing options...
cholag Posted August 4, 2008 Author Share Posted August 4, 2008 Alright, so I would have to hook everything up to the battery then? I also forgot to add, that the car is an 1983 280zxt. Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 4, 2008 Share Posted August 4, 2008 It sounds like you feel you need to scrap the existing wiring harness and start over. But why do you want to "hook everything up to the battery"? If you are going to bypass the existing harness for some of the accessories, the proper source for +12V is the output of the alternator, not the positive terminal of the battery. If you use the battery as your source, then the load from the accessories will show up on your ammeter as if the battery is being charged. And make sure you use a proper sized fuse placed close to the alternator. Choose the fuse based on the size of the wire - that's what it's protecting. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted August 4, 2008 Share Posted August 4, 2008 In the s30(don't know about the s130) the stock EFI is in a separate wiring harness than all the lights and what not. You can completely remove the stock ECM and EFI harness and everything else will still work. Quote Link to comment Share on other sites More sharing options...
cholag Posted August 5, 2008 Author Share Posted August 5, 2008 zmanco you are right, I do feel the need to scrap the hole harness and start from nothing. Do you guys think this is a good idea, or should I just work with what I have and cut out what I don't need. Also letitsnow the harness in the s130, is one big peace that hooks to everything in the engine bay. And I have a small electronics back round, but this is my first time doing anything with car wiring, so thats why I felt the need to hook it all up to the battery. But if I can build a motor, I am sure I can do this! Quote Link to comment Share on other sites More sharing options...
COZY Z COLE Posted August 5, 2008 Share Posted August 5, 2008 I suggest to you to go no further with your plan. Go to a speed shop or a good auto mechanic in your area and tell them your plan and see what they think of it.... LARRY Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 5, 2008 Share Posted August 5, 2008 I agree with Cozy Z Cole, get someone experienced with wiring to help you evaluate it. You could easily make it worse, not to mention reduce the value of the car for resale. If I was looking at a car and the seller told me he had rewired it, I'd likely run away from it unless he could demonstrate that he really knew what he was doing. And even then it would have to be a great deal or something I just had to have. Trouble shooting someone else's wiring mess is just not fun. Wiring isn't rocket science, but there are only a few right ways, and a whole lot of wrong ways to get it done. And unlike some other skills where people can write a book or give a quick set of instructions in a post like this, wiring doesn't lend itself to that. Quote Link to comment Share on other sites More sharing options...
cholag Posted August 5, 2008 Author Share Posted August 5, 2008 Just have to say, thanks to all you guys that helped and put your 2 cents in, I will be using everyones advice to help me with this. Quote Link to comment Share on other sites More sharing options...
evildky Posted August 7, 2008 Share Posted August 7, 2008 sounds like you are a bit confused, read adn reread moby'd writeup, then start reading the megamanual, then read it again, the MS needs one constant hot formt he battery, and one swithed hot signal most likely taken form one of the plugs coming from the chassis wiring to the old engine harness which I assume you have removed, this has no bearing on your accessories, if you don't understand after althat readng you might want to hire someon who has a better grasp of whats going on Quote Link to comment Share on other sites More sharing options...
rvandivort Posted November 10, 2008 Share Posted November 10, 2008 This is rather late (11.9.08), But the brain ( megasquirt or oem ecu ) is separate from the other functions. So, the other circuits are going to work as usual. If you have looked at the wiring diagrams..or physically seen them...the brain has its own thing. Lots of ground wires (for individual sensors and other functions)..and a dedicated positive feed. Quote Link to comment Share on other sites More sharing options...
rvandivort Posted November 10, 2008 Share Posted November 10, 2008 See Matt Cramer above! Quote Link to comment Share on other sites More sharing options...
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