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Switch map on external stimuli

PostPosted: Wed Oct 19, 2016 2:00 am
by lonestarrpm
I'd like to run mixed fuel and send the M48 a signal to run a different setup file.

Is this possible?

Specifically I'd like to put a tap in my fuel line and have an ethanol tester send a signal to the m48, if the ethanol level drops I would switch out map files. I would either run ethanol or pump gas, dialing it back if I was just doing pump gas.

Alternatively I could do this at startup... or
Use the same map but cut back timing and fuel dwell.

Thanks,

Mike

Re: Switch map on external stimuli

PostPosted: Thu Oct 20, 2016 4:23 pm
by AdamW
There is no way to do a complete "map" change on the fly with these older ecus. Still with a bit of imagination you should be able to get something to work. I think the problem will be however that it will be a basic 2D trim rather than a full 3D map.

One option would be to use the Secondary load table. Set up its eff calc method as "Aux V" Your Aux V analog input could be from something like a dash board potentiometer or your ethanol sensor. You would then have a fuel table overlay that could be mapped against RPM and that analog input signal.

There are also Aux V and Aux T fuel and ignition trims that may work.