I do alot of highway driving to work and class two towns over. I noticed that it takes me almost a quarter of a tank to go and get back if I hit my secondaries. I was thinking, how safe would it be to cut the power to the secondaries if I keep it around 4k under no boost? I get kind of tired of going 75ish and not being able to go a little faster on the highway because of my secondaries kicking in and killing my gas milage. A bad idea? Opinions?

 

Bad idea.
Say a semi is barrelling down on you...now you got no secondaries...you can't go faster...you end up getting runned over???

You want some kinda signal to tell you the secondaries are firing?
Run some diodes to the fuel injectors, so that you have a visual reference on when they are firing.
Turning them on or off is just a bad idea.


-Ted

 

try taking your foot off the throttle.

 

You don't understand how the Mazda rotary staged injection works. The secondaries coming on does not increase the amount of fuel injected or effect mileage. When they come on all four injectors fire at half the pulsewidth the primaries were firing at immediately before the transition. Half the flow from double the number of injectors means there's no change in fuel flow. The ECU alters the amount of fuel injected by changing the injector pulsewidth, and that's based on engine load, which is controlled by the throttle. It's not the secondaries that are killing your mileage, it's simply your right foot.

Please don't mess with the EFI system if you don't understand it.

 

look for your basic tuneup stuff and o2 sensor and see where that leads