Hey everybody i something strange going on. With communication from megasquirt to turner studio. While ecu is plugged into the cars harness. It’s a ms2 unit. When the ecu is unplugged from the car and plugged in to my external 12v power source it will connect to tunerstudio no problem. When I plug the ecu into the cars harness and key on I get nothing thought maybe it was the battery took the battery to work charged it on a gr8 charging system that took diagnostics of it as well. Everything’s good plug it back in still nothing. One thing that is also strange is when the key is plugged in to the car and I plug the 12v power source in. With key off or on it will communicate but I have a weird clicking noise coming from under the dash.goes away ones I unplug the external power source. The cars a 1.6 it worked perfectly I swapped to a different 1.6 motor and now I’m having problems connecting. Also I updated firmware last night when I couldn’t connect at all to tunerstudio. If anybody has any idea what’s going on please let me know thank you

 

Check power at the ECU connector,

 

I’m gonna check after I get out of work. Assuming this should have close to 12v at the pin

 

Assuming everything on the inside of the Megasquirt is still good (which you confirmed by plugging the 12V AC power adapter back in and it communicated), then that's the issue. All you need to communicate with it is power and ground. If you confirm that you don't have 12V on the proper pin (look up wiring diagram or ECU pinout to figure out which one), then check fuses, relays, and grounds.

 

Ill try and find a diagram of the 12v lead once I’m home hopefully it’s something simple. Everything else seems to turn on as it should. It also turns over. Just fine

 

Okay out of work checked the white/red wire at the ecu connector. No power at all. Also just realized my fuel pump is not turning on with the key. Pulled the fuel injector relay. And jumped the right pins. Fuel pump turns on I have power at the pin and it connects to tunerstudio. The relay is clicking when I put it in but nothing happens. Is there a corresponding ground or another relay/fuse by chance

 

What year car?
Has the MS ever worked in your car?

 

Yeah the car was running before I put in a new 1.6. I actually figured the problem out. I removed the air bag fuses from the block under the hood. Since I have removed all air bag components. I put them back in for the hell of it and everything is back to normal now.