rokalias

1987 Mazda RX7 non turbo, purchased for my 16 yr old son . project.
the kids put in a new clutch and rebuilt tranny. However, they did not diagram the wires they disconnected. They have given up on the car.
I need to try to repair it again.
Now, none of the dash instruments work as they all worked previously
I am hoping that if list the wiring here, someone may be able to direct me where , what goes to what.
I do have the car up on jack stands, but, non of the wires seem to match color code wise as far as re-connecting ?

Also, the car runs really strong, shifts good. However, it is now hard starting . seems flooded and now blows tons of white smoke for a bit after getting started. I am hoping that it is electrical due to the wiring and something in the injection or such is turned off.
The car has never been driven on the street except for the new exhaust and then to emission where it passed. It had pretty much sat here the past 6+ months

I have looked through the 2 manuals we have, tried to read the electrical diagrams with a magnifying glass for hours .. I have looked for a RX7 mechanic here in Nashville but no luck and stuck. I would be really appreciative of any help and will gladly call or send my contact info/ #.
I have also spoken with Mazda Trix a few times and they've been really great and helpful.

I am really in need of getting this running properly to sell .. family emergency situation and hope to not take too large of losses selling but a good deal for someone else or get it drivable again as we are in need of a family car.

Below is a list of wires.
engine compartment, driver side lower just above and left of tranny
1. yellow/red or yellow/Orange wire with rectangular plastic clip

2. Black wire with large eyelet with a rectangular black box
written on the box is ( I think) 0.47 / 250 R17G

From under car / tranny area
2 blue wires that go to a double connector > round connector

2wires, green/red and black/red that gor to a round white connector ( I don't see anything like this to connect back to)

There is a large thick (looks like a battery cable) black/yellow wire they have connected to ta lowere tranny housing bolt .. Is this where that goes ?

Thanks in Advance for any help I get and I sure need it.

RotaryRocket88

iTrader: (7)

First, you can get the S4 FSM (factory service manual) for free on the web. There are some download links listed in the FAQ at the top of the page.

For your gauges, check the interior fuses. The METER fuse should be a 7.5A if I recall right.

Oil pressure sender wire. The sender is dome shaped, and located below the oil filter. It threads into the rear iron.

Oil pressure condenser. It's normally attached to one of the clutch slave cylinder bolts. It really just needs to be attached to a good ground.

These are going to be for switches on the transmission tail housing:
1. Neutral switch: S4 FSM (factory service manual) lists colors as Green/Black & Black
2. Overtop/5th gear switch: S4 FSM lists colors as Black/Blue & Black
3. Reverse switch: S4 FSM lists colors as Black/Yellow & Red/Green

The 5th gear & reverse switches are combined w/ 4 prongs; 2 for each switch. They're non-polar, so either wire can be on either side. The reverse switch turns the backup lights on when the transmission is put in reverse. The 5th gear switch is for emissions & the shift up light (disabled in 5th).

The neutral switch bumps idle speed up when in neutral. It's pretty useless. Again, non-polar, so the wires can go on either prong.

You'll have to play with these a bit to figure out which connects where. It sounds like someone has run their own wires, or they were different from the factory. If the plugs don't match anything, cut them off and attach female bullet connectors.

Negative battery cable. The longest bolt on the bell housing (goes through the starter) is where this connects. Other bell housing bolts will be ok too.

rokalias

I really appreciate your taking the time to put together so much useful / helpful information.
You wouldn't believe how much time I have in trying to figure out what to do.
The RX7 Club has been so useful and helpful since we got our RX7

Thanks again !!!

RotaryRocket88

iTrader: (7)

No problem. I just re-wired all the transmission switches less than a year ago on my car, so I'm familiar with all the details down there. As I suggested, I just used bullet connectors and new wires to make everything connect where it should.

rokalias

I was wondering and thought that maybe one of the wires that is off might be a ground to the panel, instrument cluster .. maybe common ground .. since none of them work now and before the kids did the tranny and unhooked the wires, they were all working ?

RotaryRocket88

iTrader: (7)

Well, the oil pressure gauge won't work without the sender connected (grounds it to the block), but the others all ground through different locations. The wires you mentioned are part of the engine harness (E), but the cluster sensors ground through a mix of the front harness (F), rear harness (R), the block itself, etc... Page 50-40 of the S4 wiring diagrams shows all the connections. You can see the only wire on the engine harness at all is the Y/R for the oil pressure sender.

rokalias

you were right . 7.5 fuses for the cluster or whatever they call them .. I had 2 next to each other .. both blown.
At first I wasn't sure and tested all the main fuses in the engine compartment.
On the way to pick up spare fuses and some bullet connectors .. probably some wire too .. unsure of what gauge o get.

I found the sending unit .. cleaned and reattached and pulled a close bolt on the block and attached the ground.

I hope the kids haven't shorted something out somewhere for this instrument cluster. As I said, worked before .. hopefully just a temporary surge or something.

rokalias

I found the original Transmission Tail Housingswitches the kids took out. Unsure if the new/rebuilt tranny came with different switches and I only see one set of wires (1 switch hanging down). Maybe the other is hung up. I haven't gotten under the car yet , will tonight.
Regarding the switches, the 2 switches I found have the wires , looks like either 2 blue or 1 blue and 1 green.
The other switch has 2 red wires and 2 green wires.

Would you happen to know which switch goes in which side of the tranny. Please refer by driver side or passenger side.

I'm still struggling reading the electrical diagrams but getting better.
Also, how do you find the factory service manuals you told me about ?
"S4 FSM (factory service manual) for free on the web. There are some download links listed in the FAQ at the top of the page. "
I didn't understand where the FAQ at the top of the page was .. I looked around and tried some links.

Picking up some parts tonight, wire, bullet connectors, fuses and tester.
Also installing a new water pump.

RotaryRocket88

iTrader: (7)

This is the site I use for the manuals & parts fiche: http://www.rotaryheads.com/PDF/2nd_gen/index.html

2nd gen FAQ: https://www.rx7club.com/new-member-rx-7-technical-256/frequently-asked-questions-2nd-generation-rx-7-1986-1992-faq-fc-782402/. It is stickied at the top of the threads list for this section of the forum.

And for the switches, I found this diagram in the '86-'88 Body (a) section of the parts fiche listed on the same page I linked to above.

rokalias

I was looking around and unsure as I have a question about pulling the water pump and replacement on my 1987 RX7 non turbo.
Do I add to this thread or how do I start a new post.

I have loosened the belts,pulled the fan and taken off the adjustment brackets and according to the manual, the water pump pulley should slide off . but, it is not clearing the pulley below it .
I figured I could pull the water pump with it still loosle on it and then it would just come off when taking out the water pump ??
Any tips would be helpful so I can finish this and install the new water pump.

I can then start again on my wiring problems .. which is a real pain.

thank you