So yesterday I decided to grab the battery out of my daily and test the state of the rx7s electrical system to see how my wiring repair has been going. Previous owner snipped and ripped the 13b out for a v8 but never finished the job 🤦‍♂️

After hooking it up I confirmed that I had power to the headlights, taillights, and hazards. I believe to have traced the issue to the ignition switch not getting power because of the threads I read mentioning to test turn signals. A common problem seems to be "a spade connector 6 inches from the engine fuse box" being disconnected but Im having trouble finding it. There is a thicker wire probably around 6 gauge about 6 inches under the fuse box but I don't know if it's supposed to be the spade connector. Where does this spade connector even connect to?

Below is a pic of the mentioned wire. I have the positive, negative, and other fuse box wire that runs to the positive terminal.


If j9fd3s answers this I might just have to buy them a coffee 😅

 

lol, i like coffee! um i have no idea, and apparently its too cold to go look, but the red arrow goes somewhere, and the one green arrow should have a connector, and maybe they go together?
the hot start assist bottle is in the wrong place, and the clamp on the steering rack boot clamp is not concours correct either

 

As j9fd3s eluded to, I believe those two wires (as indicated by red & green arrows in j9fd3s' photo) are connected together. Your wire with the bare end provides 12V battery voltage to the interior fuse block and ignition switch which than powers the interior accessories.

 

Thanks for the help guys, did some testing and got power to the interior with that wire connected looks like a previous owner snipped that connector off so I'll figure out something in the meantime.

After looking over the harnesses and reading up on them I believe I have most of it figured out. There are 2 connections I'm confused about and I have them pictured below. Does anyone know if these are indeed OEM or if they might be some aftermarket thing someone installed. The brown/blue wire is on the front harness and the other is on the emissions harness.

 

The 7-pin straight connector looks like it attaches to the airflow meter (AFM). I don't recognize the connector with the single brown/blue (BR/L) wire. Maybe it attaches to a temperature or pressure sensor?

 

Does a buzzard go off when you turn your ignition on? I'm pretty sure that brown wire is the coolant level sensor. It should be attached to the sensor that goes into the radiator but looks like the PO snipped it. You'll need to ground it else the warning buzzard won't turn off.

 

Interesting that you mention that, when I hooked the battery up I actually was getting a buzzer going off a few seconds after turning the ignition to acc/on and forgot to mention that. I'll take a look at the radiator tomorrow and see what sensor you're talking about.

 

For the 7 pin connector it look like that is in the firewall area where the grommet goes to the ECU.
I think it could the the Wiper motor connector since it looks like the ABS/Cruise contrl connector is right by it.

When asking questions, add harness locations.

 

In that case it's almost certainly that wire. The sensor should be at the top of the radiator near the cap. If it doesn't exist or if you can't reconnect it you can just ground the wire. The 7 pin connect is most likely the AFM the wiper motor connection looks much different.

 

S4 or S5?
the S5 AFM is a 5 ping connector

 

Not clear on that either, but in his profile he mentions '87 NA RX7 and I assumed that was the car. Apparently, the S4 AFM uses a 7-pin straight connector (https://www.rockauto.com/en/moreinfo...192339&jsn=394).

 

Those who said it was the AFM sensor were correct, I forgot those had a fairly different looking connector compared to others in the engine bay.

On the bundle of wires that runs to the trans there appears to be a small white spade connector half way down that's been snipped. The end thats attached to the front harness is a yellow/red wire and the end that has been snipped is a solid black. This appears to be the last cut wire and it has me stumped since both transmission sensor connectors are intact. Even worse is that the partial spare harness I've been using as a guide has been snipped in the exact same spot. Here are some pics I took, any help is appreciated

 

The transmission has two switches on it. One is the neutral switch which has a 2-wire connector with a green/black (GB) and a black (B) wire going to it. The other switch has 4-wires for the 5th gear / reverse (or backup light ) switch. The reverse switch wires are, I believe, brown (BR)/yellow (Y) and red (R)/green (G) with male and female bullet connectors. The other two wires for the 5th gear switch are the two white male and female spade connectors as shown in your first photo in post #12. Here's a pic of the switch https://www.atkinsrotary.com/store/8...0-17-640D.html

 

Ok it looks like both transmission sensors are intact then. The snipped connector is located maybe 4-6 inches above the wires that run from the main harness to the transmission sensors.

Also as a side question, bullet connectors don't have polarity right? (They can be connected either way)

 

>>> Also as a side question, bullet connectors don't have polarity right?

Correct. The backup light switch just completes the circuit. One wire that goes to the switch supplies 12V and the other wire from the switch goes to the backup light bulbs which are than grounded.

 

So moving onto the fuel system and I discovered most of my injector clips were cracked or broken. This seemed to be fairly common after doing some research and it looks like there are a couple replacement options (some Borg warner part number or ebay aftermarket). I took one look at them and noticed they kinda looked like ones off a civic so I took a trip to the junkyard and snipped a set. Got home and they are almost a perfect fit! Just needed to shave off a small tab on the inside of the injector clip. Plus there are literally millions out there and most seem to not be brittle at all.

When preparing to splice them into the harness I noticed there are these 2 green plugs that look similar to the injector one but have an off-center tab. I almost thought they were injector plugs but the location didn't really make sense. Does anyone know off the top of their head what these attach to? If I had to guess maybe a solenoid of some sort. Also I believe injector wires just complete a circuit (no polarity), can anyone confirm before I crimp them on backwards lol

 

One of those connectors probably connects to the water temperature sensor (https://www.ebay.com/itm/39239187698...BoCbyAQAvD_BwE)

I'm not sure where the other one connects to.

 

The plug that branches off the injector is your water temp sensor plug. I think the other one is the by-pass air control valve but it's hard to tell without knowing the wire colors.
I tried posting a screenshot but it didn't seem to work scroll down to the bottom of this wiring diagram and you'll see emission harness. Reference that.

http://www.wright-here.net/files/man...ingDiagram.pdf

 

Thanks for the replies I think you two are right, I took another look and those 2 sensors use that style of connector. It just had me confused because of where they were on the harness.

 

Well, I don't know but I think that this repair manual of rx7 could be helpful for you. You can download a PDF from https://onlypdfmanuals.com/workshop/mazda/rx-7. Repair manual have all infromation about the repairing.