I'm in the process of building a DIY Megasquirt, and I'm trying to decide which of the three options talked about in the DIY thread is best for my application. The thread seems to do a decent job outlining the three, but it doesn't really tell me the merits of each way. I was going to go with the boomslang deal, because it looks like the best method, but I can't find the 64 pin connector anywhere. All the distributors have an 8-week lead time and tyco doesn't list any distributors as having it in stock so I'm thinking I might just hard-wire the MS in. Thoughts on the three methods would be good. Why did you pick a certain method over another?

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Wiring directly into the factory harness will be cleaner, less wire bundle, but harder to do the work as you'll be kneeling next to the car soldering all those wires in. Although the harness on a 94 where the ECU connects is actually an extension so you could bring it into the house. It's about 3 ft long and connects to the main harness up under the blower.

I got in on the group buy someone started for all the parts to build a boomslang type harness. That means I have that 64 pin connector. I'll probably not be building a harness soon so if you want to buy the kit off me PM me.

Building a separate harness makes it reversible with no damage to the car. That's always a good idea.

Are you building it to run standalone or parallel? Scott posted pics of a standalone that was built into the factory ecu case. that would be bad *** and your best option if you ask me.

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I haven't decided yet if I want to do standalone, or have the stock ECU control idle, cold start, fans and the A/C.

My limited experience with MS is that cold start is a very difficult thing to get tuned, and idle is also difficult.

I could deal with modding MS to do fans and AC if cold start and idle would be reliable, but I want the car to start and idle as well as it does now.

its just as good in my experience...

i can't speak of AC on a standalone but my car idled great with the standalone with idle/fan mods that Chad built.

Well in that case, I guess I'll just do standalone. The tuning will probably be cleaner that way.

Keep us posted on how the A/C works out for you! I'm intending to go parallel at this point but if folks start actually getting the A/C to work well then I'd prefer stand alone. Joe Perez posted some diagrams / circuit mods and theories but I don't know if anyone has fleshed them out thoroughly in the real world yet.

Crimping, actually. No reason to have to solder anything in this area, just build the DB-37 connector will 24" of wire hanging out of it, then peel back the carpet, cut the appropriate factor wires, and crimp the DB37 pigtail end onto them. In my case, I used bullet or qwik-disconnect lugs on each line, so that if need be I can pull the DB-37 end out, though it's never been necessary.

And yes, start and idle will take a bit of time to understand at first, but I wouldn't call them difficult.

I'm not going to bother with the A/C at the moment. I don't use it enough to keep the stock ECU in there just for it. Once I get the turbo project complete, then I'll look into the A/C. I will let you know though. I have it in the car, so I'll make sure it works before I'll call the project "done".

http://www.miataturbo.net/forum/showthread.php?p=256739


also you can probably still find 48 pin connectors.....the middle connector is not utilized for 90-95 installs, I use it for my extras like ebc and such.

Isn't that the only reason ppl opt for Parrellel its for realiable A/C control? Since numorous claims of for stall with Standalone, I for one will stick with Parrellel.

obd2 emissions as well I think.

I can say wiring straight into the factory harness is not the smart way to do it. I did it for my isntall over a year ago and it is def a pain to work on now.

that's because you did it as a parallel that way....

Can somebody elaborate on this? I'd like to remove it and work on it on a bench, but I can't figure out how to remove it. Or is it actually simpler to do it in the car if I have the workspace?