Hi again.
Today I discovered a horrible mess down at the ECU wires!
I´ve created a post some days ago, about my dead cluster, and maybe this
has something to do with that? (And probably more things as well)
Here are some pictures, so you can understand what mess this is.

I hope that someone know why the red wire from the ECU connector
is cut, and becomes the green and a different red!?
And why the White/blue goes to two ECU connectors, and then to the blue connector?
And why the pink wire is connected to the brown wire with a black stripe?

The shielded wires in the pictures, has the outer part connected to the ECU cover!?

They are in mixed order, hope its ok any way?
And there is a Youtube video, just in case anyone wants details?
Sorry about the bad focus sometimes.

I´m in desperate need of help on this one!

Best Regards
Christoffer, Sweden

 

What does the wiring diagram say? It has full details of all wires and their colours for every connector on every harness (and is available in the stickies).

 

I think you are going to need to go over the wiring diagrams.

This is the link go down to the bottom for the tech manuals

http://www.wrex-racing.com/web/fd/info.htm


Do you have a PFC?


John

 

Hi John!
No, I dont have a PFC.
Yes, looks like I´m in for some deep reading. (I wish that I understood more diagrams)

Christoffer

 

The diagrams are not all that bad - once you figure out which physical connector each connector schematic in the diagram is referring to (which is not always obvious) and what the various colour codes for the wires are (which are listed at the front of the electrical section).

 

This is the place of the wires that are connected to each other:


Uploaded with ImageShack.us

 

You´re right! I´m going to read it tomorrow, and maybe understand it in a week or so!

It´s strange, that the car starts and going pretty well. Not when its cold, but after a while..

 

Here's something to get you started.


I'm not sure why someone would want to connect the fuel temperature sensor to ground. They may have been trying to force the ECU into limp mode, or may have been trying to trick the ECU into using a different amount of fuel.


According to the factory service manual, pin 1P should be blank.

 

Thank you Scotty!
A good start would be to cut the wire between ground and fuel temperature then?
If 1P are supposed to be blank, the best thing to do must be to make it emty again, right?

I´ve searched the wiring diagram for the ECU page(es), but without any luck.
It´s probably just before my eyes, but I keep missing it.
In what page, in wich manual did you find the info Scotty?

Christoffer

 

Most of the connection you show in your pics are stock connection. It is normal that some wire change color after a connector. It is also normal that your shield wire are connected to the ground.

 

If possible, I would recommend contacting the person who had the car before you, or the shop that performed the wiring modifications.

It's likely those changes were made on purpose, and it's almost always a bad idea to make changes when you don't understand the system you are changing. For instance, is there an OEM fuel temperature sensor installed, or has it been removed?

I found most of the info in the 1994 Mazda RX-7 Workshop Manual , section F for 'Fuel and Emission Control systems.' There is tons of useful info in that section, look for the Powertrain Control Module (Engine) info, it will be near pages F-150 through F-165

 

If its a RHD, they may have been trying to disable the speed limiter. Might have been converted to from auto as well, not sure from the pics, dont remember everything that needs to be done.

Dead cluster? Check the Fuses under the dash.

thewird