Hank

Well, it's finally that time. I have my megasquirt all assembled and ready to go with all required mods as on DIYautotunes install article. I put together the wiring harness based on the Kag's install writeup.

I picked up my LC1 from work today and will get that installed in the morning. Is there a writeup for how to wire the LC1 into the MS? Does it replace the factory O2 sensor or do I run with both the factory and the LC1 in a different bung later down the pipe?

My miata is a 90 running stock right now. I have the Gm iat and clt, but will most likely just use the stock clt sensor and easytherm, at least to try to get going anyway.

I really need some help on the wiring into the car. I want to control fuel, spark, and idle, but keep the stock ecu in for fans, ac and what not. What wires are shared by the ECU's and which wires go only to the MS and no longer to the stock ECU? I dont care much about being able to flip a switch and switch back and forth. I am wiring everything color coded and with spade connectors so that I can unplug the MS wires and plug back the wires for stock if in a pinch to get work on Monday. There really is an overabundance of info on wiring, but it sucks trying to put together info from 10 different websites and writeups to make sure I am doing it correctly. It really has gotten confusing and I am a little overloaded with trying to sort through all this.

Thanks for the help. I'm sure I'll have more questions. Any advice or input is much appreciated/needed.

Aussie Driver

Attach your DB37 connector to the corresponding wires from the factory harness.
Power goes to power (for the factory ECU) and it is shared
Grounds go to the ECU grounds and they are shared
Cut the injectors from the factory harness and replace the connections with the ones from your DB37
Cut and connect the CAS wires from the harness to the DB37
Cut and connect the spark wires from the factory harness to the DB37
Run a new wire to the GM IAT
Share the wire for the CLT
Cut and connect the O2 sensor wire from the harness to the DB37
Cut and connect the idle wire from the harness to the DB37
Let the AFM keep control of the fuel pump for the time being and
Cut and connect the TPS wire to the DB37 connector.

If you need any wiring diagrams use http://www.madracki.com/miata/wiring.html

Hank

Thanks aussie. I got a little confused looking at kag's pinout for what color ecu wire goes to what pin on the db37. I guess that is a little different since its wired in as full stand alone and plug and play. I just wasnt sure what signals needed to be shared and which ones get replaced. I need to make another radio shack run for some different connectors and I will get started on this again today. So hopefully, there will be another megasquirted miata in the next day or so.

So, I do use the factory narrowband O2 sensor input? Where do I wire in my wideband then? Thanks again

shuiend

iTrader: (24)

Page 2 of the sticky has kags list of what wires go where along with color coding. I found that very helpfull in doing my wiring last weekend. Allthough for the 94 some wires are diffrent colors then he had.

I would go with the switches for MS. I was going to do the spade connections but that came to be a big pain to unplug and replug. The switches make it alot easier especially if you have to have it done by monday.

Hank

Update:

Everything is wired in. I am rereading the DIYautotune article to make sure I am on track. I have to wire the resistor thing into the PWM valve or whatever and load some base msq's then I'll cross my fingers and turn the key I guess. I have not yet messed with the wideband. I'll try to get it to start and then I will mess around with that to get it dialed in.

One thing I am confused about though. On kag's wiring, he refers to coils 1b and 2a, but the diy install it just calls them A and B. Is A really 1B or 2A? I want to make sure I dont get them switched. Thanks.

Hank

Alrighty. The megasquirt is in, but I have not taken control of anything yet. Still an exciting step in the right direction. I am having a problem with the rpm signal though.

I found a discrepancy in the wiring colors and could use some help.

Kag's writeup says the two rpm signal wires are white and black/white on the factory harness. My car would not run with the signal wire hooked to the black/white wire. I found another writeup on here that says to hook the wire up to the blue/yellow wire. The car runs with it hooked up to that wire, but it isnt reading correctly. Which wires are the correct signal wires to hit on the stock ecu harness.

Everything else is reading ok. I have not setup easytherm yet, so the coolant is not correct and I havent run my vac. line for the map sensor yet. Trying to sort out the rpm issue. All the wiring is setup and it will only take me about 5 minutes to take control of fuel and spark once I get to that point. Pretty cool stuff.

richard_ha

Heres one I started to make earlier

Hank

Thats looking good. Nice to have something a little more miata specific. I am pretty sure that I hooked into a blue/yellow, and not yellow/blue. I'll have to check. That would certainly cause a problem if so. It was a long day, so by that point it's totally probable that I did something stupid like that. Thanks for the help.

I have come up with 3 more questions that I need a little clarification on. First of all, I have seen some people say to hook up the TPS wires on a 1.6 and other people say not to. Which is the correct way?

Secondly, according to the diyautotune writeup, i need to install a diode across the pwm valve for idle control. Where is the valve located and what exactly needs to be done with the diode? I was a little confused by the instructions.

In Conclusion, where might I find good basemap msq's for a stock 1.6 to get started. I have been searching for them no here but havent found them for some reason. Is there another website where everyone hosts thier msq files?

I just a have a few more things to take care of here and I will try to take control of everything pretty soon and start tuning. Again, I appreciate the help. The learning curve for this thing is a bit of verticle wall, but I'm enjoying the experience. What takes a month the first time could be done in a day the second time.

Al Hounos

dont hook up the tps, just ground the signal with a resistor.
heres a pic of the diode. don't bother with idle till everything else works, one step at a time.
you can use my map or aussies but remember to change the fuel constants.

Hank

Thanks al. The idle control will be the last thing I do, I just want to get everything wired so that when I am ready to start controlling stuff, I just need to plug it into the megasquirt harness and take over fuel, then spark, then idle.

So, I dont hook up either of the two tps wires to the megasquirt? Theres tps and tps vref. Do I ground the signal wire on the miata ecu harness, or ground the signal wire coming out of the megasquirt. I still have the tps hooked up to the factory ecu and was just tapping in to share the inputs between the two ecu's.

Al, where are your's and aussies msq's located? I must have missed them. Are they posted on here somewhere.

Sorry for all the questions, just trying to sort all this out. Thanks.

Aussie Driver

Send me a pm with your email address and I'll send you my .msq

Hank

Aussie. PM sent. Thanks.

I double checked my wiring for the rpm signal input and I did tap into the yellow/blue, so that's not the problem. I'll check my board mods and reread diy's article and see what I am missing. Hopefully I will be able to get things sorted out a bit and start taking control of stuff soon.

shuiend

iTrader: (24)

Do you have d1 and d2 jumpered? I didnt have D2 jumpered on my board and was not getting rpms. Jumpered that and rpms started wroking fine.

Hank

Yes, they are both jumpered. I was pretty sure all the board mods were correct, but now I have to recheck everything. It may be something setup wrong in megatune for all I know. It's reading rpm, it just says I'm turning 90k or something rediculous at idle.

So, just to make sure I am correct here the wiring diagram on kag's writeup is incorrect. It says to tap the white and black/white wires for rpm. I do in fact need white and yellow/blue. Correct?

shuiend

iTrader: (24)

Go back over everything in the megamanual to make sure u didnt leave nething trivial out. Thats what I did and it messed me up a bit. I will let you know what wires i used tommorow. I will also look into the 90 wiring diagram to check. for you.