MyE28.com

I figured this would be the best place to post a megasquirt problem. I am running MSII with EDIS on my e28. I put a new wiring harness in over the stock one and only unplugged the fuel injectors, idle air valve, tps sensor, coolant temperature sensor, and obviously the ignition coil. My tach is dead now and i'd like to get it back up and running. I left both VR sensors in on the flywheel which I thought was all that the computer needed to run the tach. Does anyone have any ideas? Could this just be a result of having the battery unplugged for a while and having my SI battery die?

I am going to attempt to get MS to output a tach signal if I can't get this solved, but i'd prefer not to have to do that.

two choices with what you have now:

Let the moronic control the spark and get your Tach back.

Or wait until they develop the MS2/MS2 Extra code enough to add the tach output.

actually there is a third choice but this means getting rid off your MS2 daughter board going back to the MS1 chip and using MSnExtra code.

That doesn't make sense to me at all. My friend has the same setup as I do in a 535 running megasquirt II with EDIS and his tach still works. EDIS can output a pulsing tach signal. Will that work with the BMW tach?

George,
Are you running the Motronic ECU from the 533 or 735? Could there be a difference there with the 535 ECU? Either that, or it's just a coincidence that your tach quit because I've got the same setup (same stuff disconnected) and a working tach.

I have the 533 ECU still.

So your tapping off your stock VR Sensor? and Didnt touch the Original TACH output wire?

When I tapped into my Tach Output wire to Run Fuel Only, the Dash didnt like it, and I lost my Tach(though Ive read an inline resistor will fix that).

Once I switched to tapping off my VR Sensor for Full control, Tach came back and worked fine, no issues.

I also left my DME controlling the Idle Air Valve, and it idled great.