I hard-wired my fuel pump to run off of the battery (+) whenever the car is in run (with a relay). Do I even need the FCD? Just curious.

 

Yes, it's the injectors that get disabled, not the fuel flow itself. It basically stops signalling the rear injectors but continues to pump fuel (as to run off the front rotor so you don't go stalling)

 

That's what I thought, but I was skimming through the guru's website...
I found an error!

http://fc3s-pro.com/TECH/MODS/EX/exhaust.html
"One last note: by upgrading the exhaust (especially when eliminating or modifying the stock catalytic converters), it highly likely you'll run into "fuel-cut" due to elevated boost levels. Running boost ~1psi higher than stock (1986-1988 Zenki FC3S run ~5.5psi stock and 1989-1991 Kouki FC3S run ~7.5psi stock), will cause the ECU to abruptly kill the fuel pump. Please avoid running into the overboost fuel-cut!"

 

Fuel cut on a series four is 8.6 psi.

 

that's pretty strange, I was almost positive it just stopped signalling the rear injector.

 

Yep me too....always thought it just killed injectors on the rear rotor. I have seen it/read it somewhere for sure....

 

I will never fail to understand why Mazda, in their finite wisdom, chose to cut the fuel instead of the spark...

It's not like they don't know that running a rotary too lean will blow it... Ahhh! NOW I understand!!!


Bastards...