Vince Deveau

Hey everyone!
First time question on this awesome site! I own an 1986 Mazda Rx7 GXL that I bought last summer. its been extremely reliable due to proper maintenance that I've provided for her. Unfortunately I've recently run into an issue that I've been unable to solve.
let me explain.

​​​​​So I was driving down the street normally then randomly the car shut off. I rolled to a stop and popped the hood. I found that the EGI COMP 30a fuse had blown. I replaced this fuse but the car still won't fire.
I mean it turns over... but it won't catch. I have to replace the fuse everytime as soon as the key is in the ON position. I haven't been able to resolve this issue. if anyone has had the same issue or may know how to resolve my problem, I would greatly appreciate it!

thanks in advance!!
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satch

iTrader: (1)

The comp fuse powers the ECU and the emission solenoids. The outgoing wire from this fuse runs to the main relay (speaking of the 4 wire plug at that relay) and the wire color is White/Blue. W/key to on the relay transfers the voltage from the W/L wire to the Black/White wire in the same plug. Since the fuse is good w/o the key that should mean the run from the fuse to the relay is good but not so good after the relay (speaking of the B/W wire). So, you need to isolate the short in the wire. If you look at the solenoids on the side of the engine they are all powered by the B/W wire (relief, switching, BAC, EGR, port air, split air, air bypass solenoid and the pressure regulator control valve). As mentioned, the B/W wire powers the ECU and the air bypass relay also.

Now there is a large plug above and to the right of the ECU known as FEM-02 (joins the front and emission harness together). FEM-02 is next to FEM-01 (FEM-02 is smaller). The corner wires to FEM-02 are Brown/Red, Green/Black, Brown/Yellow and Light Green/Black or a Yellow based wire. Locate this plug and unplug it. If the fuse blows w/key to on then the B/W wire running to FEM-02 from the relay is shorted out or the wire running to the air bypass relay is bad. If the fuse does not blow then the problem lies after the connection of FEM-02 (emission side of the harness) and this B/W wire powers the solenoids as previously listed (the ones I emboldened).

misterstyx69

iTrader: (142)

There is a bottleneck of wires at the alternator that snakes on the front of the engine.
This area is prone to heat and the wires get brittle.
I would look in that area as a starting point.