No feedback with Megastim

[James]

A friend of mine has built up a Megasquirt for me - I have loaded it with the latest firmware 2.1.0d.

The Megasquirt is set up for VR RPM and 3 x coil drivers.

Plugging the MegaStim in - I get power and the board will communicate (it loaded the firmware and also tells me the right firmware number with "S" in the terminal)

I get no LEDs lighting up - and all the gauges in MegaTune/TunerStudio are static - some have values but nothing responds to any of the knobs on the MegaStim.

Is it because it's set up for VR? I guessed that at least the sensors would be working etc


James

[James]

To expand on this; I have got the RPM working by choosing the right trigger - it was set on toothed wheel - now its just standard setting.

So I have PMP and the I1 and I2 LED pulsing according to the RPM.

However all my sensors (IAT, CLT, TPS and wideband) are all frozen. CLT and IAT both flicker around 60c in MegaTune and TunerStudio.


James

[Matt Cramer]

I would first check their calibration, then whip out a multimeter and check the voltages at the 40 pin socket to be sure they move in response to the dials.

[James]

Checking the voltages on the megastim pots - I get 4.86 volts on the TPS and O2 (legs 1 and 3). I get nothing on the IAT or CLT though.

[James]

I checked the voltage regulator - closest to the DB9 - inside the MegaSquirt.

It's giving me 8volts - where as the Stim input is 9volts

I do get 5volts coming out though.

[Matt Cramer]

That voltage drop is caused by a couple of diodes that protect the MS from reverse wired power inputs.