Megasquirt Info Thread

[RotaryProphet]

Originally Posted by Low Impedance

im still confused on how to run the injectors. since it has two outs, would i have the injectors that are firing at the same time run one rotor at a lower pulse width?

That depends on what you're using for your intake & injectors.

The MS default is to pulse both injector drivers at the same time off the same map. On most non-rotary cars (or rotaries using the non-oem intake setup) where all the injectors are the same size, you can set it to alternate the two banks off of the same map.

So for instance, if you were running an IDA throttle body like I was for a while, you would wire both of the outboard injectors to one driver, and both of the inboard injectors to the other, and run them in alternating mode. You can set it up with one driver per rotor, but you lose a hidden benefit. In alternating mode you are basically running the engine off of two injectors, but as the load increases the injectors will start to overlap; one bank is still firing when the next starts. Eventually at 200% (calculated) pulsewidth, both banks are firing all the time. This gives you a very good dynamic range, and makes it easier to idle on big injectors.

Now the tricky part comes in when you have differently sized (staged) injectors, or when you have an intake setup with secondary throttle blades that don't open immediately (sound familiar? Both of these are true in various 13b configurations).

At this point you have to run dual table. Wire the small/primary injectors to one bank, and the large/secondary injectors to the other. Then you have to map out both injector banks individually. One thing to note is that you can't put a zero into a VE table bin to stop the injector from firing at all (under most firmwares; check local listings). Instead, when you want an injector to not fire (ie, secondary injectors before the secondary throttle opens) put a "1" in the VE bin, and it'll put out -almost- no fuel. Close enough to get the job done, at least.

[Whizbang]

so i would then have one injector on each rotor firing at the same time?

[RotaryProphet]

Originally Posted by Low Impedance

so i would then have one injector on each rotor firing at the same time?

Yes. Even in boingers the injector is firing against the closed valve more often than not, in a rotary where the intake is almost always open to one rotor face or another, it doesn't have any negative effect to fire both rotor's injectors at once.

[Whizbang]

works out then. Ill wire it like that.

[Whizbang]

I have a DIYAutoTune built MS unit. I thinks its an MS2. I am also using a USB to serial adapter (eek).

I have the FIFO off so there is no buffer. I have tried both sets of rates (matching on each end). Com ports should be correct as well. I still wont rule out the cable but i have no access at the moment to anthing else.

Getting "no response".

When i turn the key to "on" i get a quick flash from the LEDs but none of them stay on. Should any of them remain on without the engine running? I have the wiring in the rear as per the mega manual with only the one voltage source from a switched ignition.

So...any thoughts? I have heard of having to flash the ECU with firmware (this has never been used prior nor have i had it communicated). But i can't connect to begin with.

[Whizbang]

i downloaded the newest DIYautotune package and am going to try it tomorrow.

One question i have that is how does the whole "project" selection thing work when i open megatune. Seems more like versions of the program than a "project". I had a car1 option on the laptop im using right now, but the tuning laptop lacked this. car1 had a similar interface as the FAQ on the Rx7club's megasquirt forum for the constants. But most of the other listing i do have, like MS-2 Extra 2.1.0 from the list, is different.

[Whizbang]

Got the car started! Ill attempt a good write up on this plus some base information that someone could use to get their car running (ie map and settings)