Sending a custom output for economy gauge

[feelingsupersonic]

Weird question, my previously-Motronic car has an economy gauge that shows real time gas mileage by looking at road speed, RPM, and a fuel injector load signal. That injector signal was sent by the stock ECU which is gone in favor of a Microsquirt.

Is there any support in TunerStudio to broadcast a "custom" signal? I think it's similar to injector duty cycle PWM signal. However I'm using different injectors than stock, so the signal will need to be massaged in order for the economy reading to be accurate. Anyone have pointers? It's not mandatory I get it working, but I have every other gauge working except that one.

The stock signal was a square wave, much like an injector signal, so that would be the starting point. Thanks for any info!

Michael

[jsmcortina]

This is a firmware question. What Megasquirt ECU do you have?

James

[grom_e30]

i did this on a BMW E30 i was running sequentially so just connected the fuel rate signal to one of the injector out puts which worked fine until i fitted bigger injectors then the reported mpg was off. i ended up using an arduino to read the injector p/w and to calculate a scaled signal output to send off to the mpg gauge and that works well. as you have a microsquirt i don't think there is a way to do this using the ecu.

[feelingsupersonic]

This is a firmware question. What Megasquirt ECU do you have?

James

Sorry I'm running MSExtra 3.3.3 if I recall correctly - I'm a couple hours away from the car but it was up to date about a month ago when I last checked. I know 3.4.0 is out now, though. It's a Microsquirt V3

i did this on a BMW E30 i was running sequentially so just connected the fuel rate signal to one of the injector out puts which worked fine until i fitted bigger injectors then the reported mpg was off. i ended up using an arduino to read the injector p/w and to calculate a scaled signal output to send off to the mpg gauge and that works well. as you have a microsquirt i don't think there is a way to do this using the ecu.

Thanks for the info. I'm running 346 cc/min injectors vs the stock 258 cc/min so I'll definitely have to go that route if I pursue this further, it sounds like.

[grom_e30]

if you do go the arduino route your injectors are roughly 35% larger so if you read the pw from the injector and times it by 1.35 should get you some where close to where it should be.