1.6 Harness into 94 1.8

[ADOBOMiata]

[Short Story] My sort of built 92 chassis got into an accident and there is no way to recover my lost, besides taking the parts off and transferring into another shell. A friend of mine is donating me his spare chassis (94/95 M edition) because he has no use for it. He is taking the drive train, brakes, engine harness, and suspension components.

Has anyone swapped their 1.6 engine harness into a 1.8? The reason why I want to do this, is because I already modified many parts of my harness to run a 1.8 (NB) tps, IAC (NB), toyota cops, and had the car safely tuned. It is currently making 295whp 271tq

[Parts List of 1.6 Chassis]
Engine:
+99' Engine (1.87)
+ARP Head studs
+ARP Main Studs
+2001+ oiling system
+ACL Race bearing set (Main, Rod, Thrust)
+Fel-Pro Headgasket set
+M-Tuned H-Beamed Connecting Rods
+84mm - 9:0.1 Wiseco Pistons
+Supermiata HB
+1mm Oversize Valves (Supertech) Exhaust and Intake
+Supertech Springs, Retainers, etc
+Garage Star Water Pump Pulley (1.8)
+Fidanza Adjustable Cam Gears - Silver
+Fab9 Solid Motor Mounts 88D
+NGK Nickle 1-Step colder plugs Gapped at .030 (BKR7E - O'rileys part ref: 4644)
+ 94 1.8 Alternator
+GarageStar Alternator Pulley
+ 2000 NB Starter
+323 GTX Turbo PCV
+Rotella T6

Intake:
+HellaFababrications Custom "Race" Aluminum Intake Manifold
+Skunk 2 Throttle Body
+2.5" Intercooler piping
+HKS Mushroom/Superflow Air filter

Exhaust
+Custom Equal Length Bottom Mount turbo manifold- Fabricated by HellaFab
+3" Stainless Steel exhaust (V-Banded)- Fabricated by HellaFab
+3" Stainless Steel piping (Cat delete- V-Banded)- Fabricated by HellaFab
+3" Stainless Steel Vibrant Muffler (V-Banded)- Fabricated by HellaFab

Cooling
+Begi Spacer w/ fittings
+Water Neck Delete - Freeze plug + Custom Block-off plate
+Coolant re-route (Followed RevLimiter's +Write-up) w/ Escalade hoses
+Ebay hose Splicer
+Flipped lower water pump housing
+Fab9 Stage 2 Intercooler

Turbo
+IWG = Internal Wastegate
+BorgWarner EFR 6758 (3" exit)
+Turbosmart BOV Fixed 50/50

Fueling:
+Deatschewerks (sp?)200 fuel pump
+1000cc Injector Dynamics
+FM Dual Fuel rail

Electronics:
+Megasquirt PnP v2 engine standalone
+Turbosmart Manual Boost Controller
+Innovate MTX-L Wideband
+IAT sensor/Speed Density Sensor
+Custom Toyota Coil-on-plugs (1.6)
+Autometer Boost Gauge

[90blue]

Both cars are OBD 1, so it should be a good swap.
How much of the harness is he taking ?
Just the engine part ? and you will have a better time doing this.

It would be easier if you just bought him a harness and have him leave the one in the car alone.

I cant imagine swapping the entire harness.

Hope he does not cut it out.
Good luck

[ADOBOMiata]

Both cars are OBD 1, so it should be a good swap.
How much of the harness is he taking ?
Just the engine part ? and you will have a better time doing this.

It would be easier if you just bought him a harness and have him leave the one in the car alone.

I cant imagine swapping the entire harness.

Hope he does not cut it out.
Good luck

He's taking most of the harness. All there's left is the interior harness.

[ADOBOMiata]

Will I need to only transfer the 1.6 engine harness? (Fuse block, ecu harness plugs, etc..)

[Demon I Am]

you'll probably need to swap EVERYTHING, or do a lot of cutting/hacking/praying

[wannafbody]

Seems like too much effort, IMO

[HarryB]

Silly question; why don't you transfer everything from your old car to the new one?

[kung fu jesus]

I've swapped the front harness on my car for a clean one. It isn't difficult, but if I were to do as you are, I would swap over the entire harness, including the rear. I would mark and label connections, look at factory service manuals between both cars, and take lots of pictures. You will probably want to swap over the dashboard, if intact, too. The issues you could run into are mounting points for the front harness behind the dash. The 1.8 cars, the ECU in behind the passenger seat, the 1.6, as you know, is in the foot well. So, strip both cars, lay in you harness, reassemble.

[ADOBOMiata]

Silly question; why don't you transfer everything from your old car to the new one?

This is the original plan. Since I have the dash and everything else that works as a 1.6 harness.


I've swapped the front harness on my car for a clean one. It isn't difficult, but if I were to do as you are, I would swap over the entire harness, including the rear. I would mark and label connections, look at factory service manuals between both cars, and take lots of pictures. You will probably want to swap over the dashboard, if intact, too. The issues you could run into are mounting points for the front harness behind the dash. The 1.8 cars, the ECU in behind the passenger seat, the 1.6, as you know, is in the foot well. So, strip both cars, lay in you harness, reassemble.

I figured it wouldn't be too bad. I memorized most of my harness (1.6) since I wire tucked 2 1.6 and replaced the engine harness numerous times (for other Miata enthusiasts)

[ADOBOMiata]

Ah I just realize the new shell has ABS and power steering. Hm. Possibly cap the ps lines on the rack and move the brake lines from the 92 shell to the 95 shell.

[kung fu jesus]

Or remove ABS, swap over front subframe?

[Rogue]

Suspension are interchangeable, just remove the sensors.

OTOH….ABS is a separate system, you may could keep it.

[ADOBOMiata]

Or remove ABS, swap over front subframe?

Would it be easier to "loop" the ps lines that are on the steering rack? I was thinking swapping the brake lines from my 92 and use the calipers/rotors/pads (since they are already 1.8). The ABS module is alerady damaged.

[ADOBOMiata]

Thank you Mazda Roadster members for the help.

[kung fu jesus]

Would it be easier to "loop" the ps lines that are on the steering rack? I was thinking swapping the brake lines from my 92 and use the calipers/rotors/pads (since they are already 1.8). The ABS module is alerady damaged.

You can do that with the PS rack. It's pretty well documented around the web for guidance.

If the ABS is damaged, me personally, I would remove it, but weigh out the possibilities of salvaging it to make it work.

[ADOBOMiata]

So I spoke with my friend who is taking the motor from the 94 m edition. I asked him if we could trade ecu's (since they're both megasquirt pnpv2 and both will need to be retuned.) and that way there is less labor on our end for the harnesses. I will definitely need to figure out how to wire the NB tps onto the 94 harness and NB IAC onto the 94 harness.

[ADOBOMiata]

ah.. figured out
94 -> 99/00

Red (Remove)
Black/Blue -> Black/Red

Reference link: http://www.miataturbo.net/engine-performance-56/definitive-vvt-swap-into-90-97-chassis-megathread-80469/
Light Green/White -> Light Green/Red
Red/Black ->Green/Black

[Rogue]

Would it be easier to "loop" the ps lines that are on the steering rack?
Manual/PS racks are interchangeable…..plenty of info out there on depowering, but its not just looping hoses.


I was thinking swapping the brake lines from my 92 and use the calipers/rotors/pads (since they are already 1.8).
Calipers are useable, but there will be some replumbing to delete ABS.
Other than Hydraulics and sensors the ABS/Non-ABS cars are the same.
ABS does use a proportion valve with more rear bias. :encouragement:

[ADOBOMiata]

Manual/PS racks are interchangeable…..plenty of info out there on depowering, but its not just looping hoses.


Calipers are useable, but there will be some replumbing to delete ABS.
Other than Hydraulics and sensors the ABS/Non-ABS cars are the same.
ABS does use a proportion valve with more rear bias. :encouragement:

Ah! Never knew that. I might upgrade to wilwoods or something. Besides taking apart the steering rack, I read the quickest way is to drain the steering rack and use the plugs that Miata roadster sells? Correct me if I'm wrong please.

As for the ecu/tune issue, if I swap the engine from my 92 chassis (it's a built 99 engine) everything should plug in correctly with minimal modifications (with splicing the NB tps and NB IAC onto the 94 harness). If my theory is correct, I could copy the map from the 1.6 MS Ecu and burn it onto the 1.8 MS.

[Rogue]

Besides taking apart the steering rack, I read the quickest way is to drain the steering rack and use the plugs that Miata roadster sells? Correct me if I'm wrong please.
I'm a true Manual Rack guy, I did loop hoses about 15 years ago and liked that less than I like P/S.
I then started acquiring true Manual racks and never looked back.
On a depower...FM has some tech info, but I know it requires welding up a flex joint.
http://www.Flyinmiata.com/tech/depower.php

I'm putting a built 99/00 in my '90, but at this point just doing a basic 1.8 swap with a 'squirt.

[ADOBOMiata]

Hm, I see. kungfujesus advice would be the best decision. (swap the front subframe)