Electrical questions
 

I would like to buy and install a new + cable, and a - cable. What length should I get for + and what length for -?

Also, what is a good switched source in the engine bay? I need to have a switched + or - to run to my RPM switch so it is only on when the car is running. My RPM switch is mounted where my old Sub Zero starting assist bottle was.

Thanks!

I think the ECU check connector has 12v switched in it somewhere. Not sure what pin though. Or you could run a relay off of your stereo wire, lol.

As much as you need. 10 feet of each should be enough. Use 12 AWG.

Well, according to the wiring diagrams in the Factory Service Manual and Haynes manual, the black/yellow wires at the ignition coils are a great source for switched 12V. This is also covered in my e-fan install page: http://www.aaroncake.net/rx-7/efaninstall.htm

12 AWG? Doesn't that only hold around 40 amps? Or did you mistype and mean 2 AWG?

Autozone can get you the exact lengths that you need for each wire and even include a connector to tie in the alternator wire. I would also assume almost any other decent autoparts store could do the same thing.

Thank guys. I will probably run from the coils.

More then likely I will be re-grounding a lot of ground spots. Pressure sensor and coils are probably the main ones I will be grounding. Any others you can think of while I am at it?

Both are a waste of time. Read this.

http://aaroncake.net/RX-7/grounding.htm

The one under the intake manifold and the ground wire going straight to the ecu are the ones i'd worry about.

Same thing...

For some reason I was thinking this was for a fan installation?! Maybe I am on crack (or have not smoked enough crack).

If this is for a battery relocation, the minimum thickness is 4 AWG. 2 AWG is much better, and 00 welding cable is best. 15 feet of the + is required, but only a short section to ground is necessary. Though I like to ground the battery to multiple points (one at the battery, one at the ECU, one in the engine bay, one on the engine) so you may need a lot more cable if you take that approach.

Of course you will also need the appropriate circuit breaker (150A w/manual trip lever) to mount at the battery.

For a switched source use the black/white wire at the six socket, Green , check connector.

The coils/ignitors are grounded thru the base of the coil/ignitor assy. In other words the studs/nuts that hold the assy down. It's a waste of time/money to add a gnd wire to something that is bolted to the chassis which in turn is attached to the battery gnd wire at a location just below the left strut tower.

I just repeated what was said in the posts above. Reaffirmation thing.

And the ring terminal on the rear rotor housing with two black wires IS the ECU ground. Located about three inches to the left of center line of the engine. Reaffirmation thing.

Hey thanks guys!

I read Aarons thing. Didn't even know Aaron had his own site.....

This isn't for battery relocation. I can't afford a box right now. It is just because when I looked at my + cable coming off the batter, all the rubber that used to be around the wire looks like it has melted off. It also looks like parts of the ground wire have been melted too.

It has been like that since I bought the car. + completely not insulated.

So, I thought it would be a good idea to get that done while I do a few other things.

Thanks for the info.

Also, is 10' really needed for each? Even if not relocating the battery? I am probably just going to pull the wires out and measure them, but the cables I am buying are premade and have the terminals on them already.