Wiring Questions and Other General Madness
 

Hello, I'm putting together a 1987 Turbo-II and I realize I've got a lot of questions (mostly related to wiring), so I'll cram them all here.

There are two separate bullet connectors on the sensor on the bottom of the radiator. What exactly is this sensor and does it matter which wire you plug into which end?

https://cimg6.ibsrv.net/gimg/www.rx7...019d42f41d.jpg

Currently my biggest headache: there's this wire, green with a black stripe, that branches off from the passenger side portion of the engine wiring harness near the same point that the BACV and ACV solenoids branch out at. It ends at a single terminal female Delphi 56 connector. Can't find it in the Haynes wiring diagrams. Does this connect to the sensor on top of the water pump housing? What is that sensor anyways? Is it a second coolant level sensor besides the one on the radiator?

https://cimg7.ibsrv.net/gimg/www.rx7...4d34112822.png

Lone female bullet connector by the trailing coils. What's this for and what's it connected to?

https://cimg4.ibsrv.net/gimg/www.rx7...ba5c36b230.jpg

I don't recall why, but I tore the wire connected to the connector that leads to the oxygen sensor and cannot find a wire stub anywhere. Where on the harness did the oxygen sensor wire to?

Also, relative to the block and upper intake manifold, how was the passenger side engine wiring harness routed and secured?

Also part of the passenger side engine wiring harness. Where does this ground attach to?

https://cimg1.ibsrv.net/gimg/www.rx7...2e8679e0e8.jpg

Part of the wiring that branches off and connects to the ASV, a set of injectors, and that other useless thing on the UIM. Is this supposed to double as a ground or is it just a way to secure the wiring?

https://cimg0.ibsrv.net/gimg/www.rx7...92ba022937.jpg

I've no idea what the heck this is. It's on the driver's side. Is it some sort of ground? Where does it go?

https://cimg8.ibsrv.net/gimg/www.rx7...8f1d13c68e.jpg

Next to the thingymawhatsit on the harness is this ring terminal. Presumably another ground. Where does this go?

https://cimg7.ibsrv.net/gimg/www.rx7...bf2accf4f5.jpg

Found next to the fuse block. Is this just a diagnostics port?

https://cimg4.ibsrv.net/gimg/www.rx7...f3c1732b3a.jpg

On the front driver's side strut tower. No idea what this is supposed to secure.

https://cimg5.ibsrv.net/gimg/www.rx7...95479fc22e.jpg

Same thing near the dipstick.

https://cimg3.ibsrv.net/gimg/www.rx7...44d5370f55.jpg

What are the chances of these injector connectors staying secure?

https://cimg2.ibsrv.net/gimg/www.rx7...59669524b1.jpg

Will any old rubber hose, like one for fuel injection, work for replacing power steering hoses like this one?

https://cimg9.ibsrv.net/gimg/www.rx7...4e6ab8d14a.jpg

Sorry for the stupidly long post. Any help would be appreciated!

OK I'll do my best here the double bullet connector on the radiator is a radiator temp. switch if the plugs do not appear specific in size/color then I do not believe it matters, the coolant level sensor is on top of the radiator
The green with black wire a pic would be helpful
IIRC the top of the water pump is a Thermo sensor or thermal switch on the S5 thermal sensor is on top of thermal switch is on the bottom
The single black connector at the trailing coils it's hard to say without a better picture the leading coils gets a single black connector(and a wht.) the trailing coils should be two white connectors and a single yellow wire with green stripe
The oxygen sensor should be a single black shielded wire between the passenger suspension tower and the BAC valve it should leave the wire harness near the injectors IIRC
The two strand ground should bolt near the top center of the radiator on the support
That appears to be a fastener if it is not connected internally to that wire loom as a ground
The next two pictures are grounds at the bottom of the driver side suspension tower and above the frame both utilize the same bolt hole
I believe that may be a diagnostic port
Those keep your spark plug wires organized
I would try and source new injector clips and connectors next time take the metal "C" clip off the connector before you pry them apart
I would try and purchase a new OEM hose from Mazda
Sorry most of this is going off memory as my motor and harness are out of my car
GL Rikk

Pic #6...the ground with little black box ...Is a ground for the oil pressure sensor and it attaches to the bellhousing via the slave cylinder.

Yup, there's different colors on the wiring

https://cimg5.ibsrv.net/gimg/www.rx7...d246b360cf.jpg

It actually originates a little further up on the harness. I had to strip it back to get to more of the wire since it ripped right at the harness wrapping. Like I said, it terminates at a Packard 56 single terminal female connector.

https://cimg7.ibsrv.net/gimg/www.rx7...adc06747b5.jpg

And here's a wider shot of where it originates from. I replaced the connectors for the ACV solenoids with some Weatherpacks. The originals were Packard 56 double terminal connectors just for reference.

https://cimg3.ibsrv.net/gimg/www.rx7...d3796d337a.jpg

I have an S4 so.... What am I looking at?

https://cimg6.ibsrv.net/gimg/www.rx7...bdc55d1a6d.jpg

Whoops, I meant the leading coils. That would probably explain a lot, huh.

https://cimg7.ibsrv.net/gimg/www.rx7...1c14cc1548.jpg

And now that I looked, the trailing coils also have the same problem. Same connector style, just white.

https://cimg4.ibsrv.net/gimg/www.rx7...b12264af41.jpg

Is this it? It's right next to the BACV connector. Originally, I dismissed the idea since I hadn't stripped back the insulation, which made it look like the wire gauge was miniscule compared to what was on the torn connector. It still looks like there's a bit of a discrepancy.

https://cimg0.ibsrv.net/gimg/www.rx7...7fcf374f59.jpg

Err, do you have a picture of this? The two-stranded ground is physically close to the solenoid connectors, so I'm having difficulty imagining how this bolts to the radiator support.

https://cimg3.ibsrv.net/gimg/www.rx7...0a9c1cba82.jpg

Okay, I'll try to figure out where it bolts to.

So... which is it? And if it's bolted to the slave, is this where it goes? Sandwiched between the slave and the bolt?

https://cimg6.ibsrv.net/gimg/www.rx7...77a4a62f68.jpg

Also, the main ground: I'm having difficulty finding where it bolts to. You're certain it's not somewhere on the frame? The ground originates from part of the harness that is near the starter wiring, which makes it difficult to reach the base of the strut tower. That, and I can't see a bolt hole that's as big as the ring terminal with all the clutter in the way.

https://cimg8.ibsrv.net/gimg/www.rx7...d569305710.jpg

Alright, sweet, one less to worry about.

Is there a specific orientation to these things? I bent them out of the way when I originally took apart the car, so I've no idea which way they faced normally.

I did, though the dirt and grime kept it stuck on pretty badly. I'll try rummaging around a local junkyard. Are there any cars you know of off the top of your head that have the same plug? It's for the 550cc low impedance, square/center EV1 connector.

I would have already done so if it wasn't so blazing expensive. Well, whatever, I needed to go to the dealership anways.

Also, found some more mystery connectors:

There are two in the picture, the 4-terminal connector and the 2-terminal connector. This is next to the passenger strut tower, by the MAP sensor. The 2-terminal one is hidden in the back with that huge insulation boot.

https://cimg6.ibsrv.net/gimg/www.rx7...4afbe78d8e.jpg

And a 6-terminal connector that branches out from the part of the harness that wraps around and under the nose of the car, near the oil cooler. It physically only has 4 terminals though.

https://cimg7.ibsrv.net/gimg/www.rx7...3c76756403.jpg

Any ideas what these plug into?

And also, thanks for all of the help!

I was wrong IIRC there's more than one but the "black box ground" you are referring to is attached to the factory bolt below T1 on the trailing coil(which mounts the coil to the tower)
The O2 wire can become hidden back between the motor and trans
hope this helps

The Yellow plug in the Black boot is the fuel check connector. And when posting pics of plugs/connectors it would help some to provide not just the amount of wires in the plug but also the wire colors as the FSM wiring diagram then provides clues.

1. Double Bullet Connector: Sub-Zero Start Assist Thermoswitch
2. Single 1/4" Tab Connector: A/C Fan Thermoswitch (Triggers A/C fan when engine is about to overheat, 195 degrees for S4NA, 207 for all other FCs)
3. Female Bullet Connector at Trailing Coil: Test Connector for Trailing Coil
4. Harness Routing: Under the UIM, then along the firewall and underneath the Cruise Control Actuator bracket on Passenger side, under the Brake Booster on driver's side
6: Ground w/two black wires: Main ECU Ground, it is bolted onto the shortblock. This is the one that's responsible for the famous 3800rpm hesitation
7. Wire Bendy clip: useful to route harness nice and clean
8. Capacitor: Smoothes out pulses on the Oil Pressure Sender
9. O2 sensor wire color: I'm not sure offhand, check the FSM's Wiring Diagram to be certain. Then splice, re-bundle and route nice and pretty
10. 6 pin connector near DS Strut tower: Auto Adjusting Suspension Connector
11. Oil Dipstick unknown device: Spark Plug Wire routing clips
12. Second unknown device: Same as 11
13. Injector Connectors: Replace them, they're only ~$10 for four. Would suck to blow your engine if one came off like it did to Aaron Cake :blush:
14. P/S Hose: I don't see why it wouldn't work, but some braided SS would be a good idea due to the high pressure the system can see. Our Power Steering systems use Dexron II ATF, a very common fluid so it should be pretty easy to find a suitable hose.

I left the one under the trailing coil untouched; I just found it and it’s still covered in dust. I’m just going to bolt the other one to the slave and be done with it.

FSM and Haynes says it’s solid black. Wired it up to the one next to the BACV already. Realized none of the other wires have the same, super fine stranded wire that the O2 sensor’s wiring does, so I went ahead with it.

Alright, I’ll update with the wiring colors in the next post.

Since it’s just a switch, shouldn’t I be able to plug it it regardless of direction?

So this one is the green w/ black stripe wire I was trying to find?

Yay connectors I can ignore. Still a little unclear as to how the harness spiders around the UIM area, but I’ll figure it out.

It shall be cleaner than a baby’s buttocks.

Also, if I’m not mistaken, they can go anywhere on the block, right?

Do you know where it bolts to?

The one next to the fuse box, right?

Kind of having troubles imagining how the wires are supposed to be routed now.

Replaced the two that were problematic, since the others were completely fine. I have to say though, this design is amazing.

https://cimg6.ibsrv.net/gimg/www.rx7...fb002959ea.jpg

Bought the OEM one. Which is honestly a little weird, since I plan on converting to a manual rack eventually anyways. Ah, well.

Also found where the larger ground on the driver’s side goes: starter motor’s long bolt. Yay.