So I'm probably going to be swapping over all my stuff to a 1.8 shell because of some pretty bad rust. https://www.miataturbo.net/forum/t39830/
The donor car is a stripped down 1.8. What do I do about the wiring harnesses for the motor and my MS? Do I need to swap in the harness from my 1.6 car?
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Any reason you don't want to just build a new harness for the MS? Seems like it'd be a hell of a lot simpler. If the new car is a '94-'95, there are only a couple of wires that'd need to move.

 

If all I would need is a new harness Id definitely just have Scott build me one. The car is a 96, how much of a difference does that make?
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a 96 is pretty different, youll need a new harness. but i also recommend getting a new BEGi turbo manifold and using the 1.8l, then giving me your built 1.6L

 

hey get in line.

 

What are the differences between the 1.6 and a 94-95 harness?

 

So you're putting your current running gear into the new car?

All the wiring harness are different. There are a lot of "little" differences that make it a not so great idea (ignition, fans, TPS, etc). Not impossible, just not very fun.

One solution would be to rip out all the engine wiring and build your own harnesses from scratch. You could save a ton of weight and run the harness super cleanly. That's probably about as easy as anything else.

Another would be to convert your MS to 96 standalone spec and plug it into the existing harness. You will still have work on the engine side of the wiring harness, changing connectors out, possibly lenghtening wires that may be too short (CAS comes to mind).

Or, here's an idea. Since we're running BP engines in B6 bodies by using B6 sensors on the BP, maybe you can run a B6 in a BP body by using BP sensors. That would save some wiring hassle. Still need to modify the MS to 96 spec.

Really you should run standalone anyway. Only reason to not run standalone is OBD plug in emissions.

 

Same as the difference between a '90-'92 (or Fed '93) and a CA '93.

Two injector wires.

The 1.8 cars (and the CA '93) run four separate injector channels. The earlier cars ran two-channel batch injection.

 

That's true, Joe, but like I've already stated there are a lot of differences. Ignition system is very different. TPS sensor is different. Coolant temp probes are different. Cooling fan activation scheme is different. ETC.

There are probably more differences than similarities when you start breaking it down.

 

Not from the Megasquirt's perspective. Both are +5 active-high.


Someone upgrading from a 1.6 is not currently using TPS, so they can continue not to use it.


They're wired the same.


Since he's parallel, the stock ECU will keep right on running the fans.

Etc.


Moot point, of course, with the new vehicle being a '96. I'm with you, in that he should go standalone. No inspections of any kind in FL.

 

Got ya Joe. You're looking at the MS' harness. I'm thinking about the car's harness.

You're right in that regard. The 'squirt is the same, just need to re-work the patch harness some. Pinouts are different.

 

Don't do a 1.8 shell, don't do it, don't do it. They are 100+lbs heavier than an early 1.6 shell. This is the ONLY thing I regret about my car - not buying a '90.

 

what makes them heavier?

 

The doors are lightest in the 90. I can't picture any other body differences.

What are we calling "shell"? NA8 is going to have extra bracing, larger fuel tank, and a second airbag. Is that part of the shell?

I'm assuming that there's no suspension on the shell, so we can't look at the heavier brakes, nor can we look at the heavier diff.

 

I'm thinking taking the engine harness from my 92 and putting it in the 96 might me easier for me. Both cars would already be stripped in and out. As for building a harness, that's not for me. Aside from swapping the engine harness what else would I need to swap over?
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http://www.lightweightmiata.com/beast/rewire/

*****

 

That sounds like the hardest solution possible to me.
Running BP sensors on the B6 motor would be far simpler.

If it were my car (and I didn't have emissions like you), then I'd strip the hell out of the new body and run my own harnesses. Wonder how much weight it would save, 50-100lbs?

 

After you
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No, I'm thinking swapping my engine harness from my 92 into the 96 along with my drive train would be the easiest and quickest way. Building a harness is out of the question, I honestly do not have that ability, nor the time or interest. Aside from the ENGINE harness, what other part of the harness would I need to swap?
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You'd need to compare schematics from both cars. I'd wager to accomplish what you're talking about, you'd end up needing to transer the entire front end harness and dash harness. Doesn't seem worthwhile to me. Don't know why you're afraid of running wires. You're doing a custom engine swap, so you're going to have to get comfortable with it.

Seriously, why not run BP electronics on the B6? I think the only complication is going to be at the throttle body, where you'll just use the B6 plugs on the existing wiring harness. This will save you hours of frustration.