Megasquirt goes offline during cranking?

[scorpio12]

My Megasquirt 1 is powering off while cranking ( after finally getting it started last week)...so I installed firmware for msns and i still get the same problem...

In Tuner studio it "goes offline" when the tach signal comes in then comes back online a few seconds after I stop cranking.
Any way of testing the relay board...or current draw through relay board etc? the three relays seem to work when bench tested.
Voltage drops during cranking from 12.5 to 10.9 volts ( could that be it?, isnt this normal?)

Any ideas why this would happen?

Megasquirt one 2.2 with msns firmware
Relay board

[Matt Cramer]

That voltage drop shouldn't be an issue. I'd first check that the switched power terminal isn't losing power.

[ehrnst]

Could you have wired switched 12v through an unloader relay, without you knowing?

[scorpio12]

Hi Ehrnst.... No...switching circuit is Straight to battery with small alligator clips I use to power it or switch it off

It's all bench driving my engine...

[scorpio12]

Guys this was happening just before I updated to msns and now still happens..



The " fan 4 output" flashes on and off constantly on the bottom of my tuner studio main gauge page?

The megasquirt is maintaining power while it goes offline as I tested this with a meter ...

Xg1 is jumpered to xg 2 and this was the case even before I upgraded from b and g to msns

Configuration error flashes up very briefly on tuner studio as it goes offline along with a few other random things...

What could it be?

[slow_hemi6]

How temporary is this set up you are trying. Ms hates weird ground loops. How are you achieving the grounding of the ecu etc?

[scorpio12]

How temporary is this set up you are trying. Ms hates weird ground loops. How are you achieving the grounding of the ecu etc?

All Grounds are straight to Battery negative ...

When I can get the system working well then I will finish that part of the install...it's a 4 year project on a 1979 porsche... I want to know the megasquirt aspect is working before I design a under dash panel etc for it..

[slow_hemi6]

Take some time to read this page. http://www.msextra.com/doc/general/grounding.html

[scorpio12]

Take some time to read this page. http://www.msextra.com/doc/general/grounding.html

Hi Luke i had a read through.... I may have explained wrong....
All my sensors etc ground through the megasquirt relay board.... The relay board itself grounds to the battery negative so it looks as though this is consistent with that page..

[slow_hemi6]

what kind of tach input is it? coil - triggered?

[jsmcortina]

Take some time to read this page. http://www.msextra.com/doc/general/grounding.html

Hi Luke i had a read through.... I may have explained wrong....
All my sensors etc ground through the megasquirt relay board.... The relay board itself grounds to the battery negative so it looks as though this is consistent with that page..

That page says to ground to the engine, not the battery.

James

[scorpio12]

Take some time to read this page. http://www.msextra.com/doc/general/grounding.html

Hi Luke i had a read through.... I may have explained wrong....
All my sensors etc ground through the megasquirt relay board.... The relay board itself grounds to the battery negative so it looks as though this is consistent with that page..

That page says to ground to the engine, not the battery.

James

Hi James I gave I a shot...still the same problem, megasquirt powering off every time I crank... A datalog shows that megasquirt is still getting adequate voltage during cranking... I even powered megasquirt fom a separate 12 v battery to that doing the cranking....and it still did it?

Sometimes but not all the time, tuner studio shuts down when megasquirt turns off during cranking ( never turns off when just power cycling the relay board switched 12 v)

A multimeter shows that the switched 12 v continues to get current even when megasquirt powers off then on...

It seems to power off for 3-4 seconds before coming back online?

I stick on the stim turn the dials and tuner studio reads them nicely and the little stim injector lights flash....

Maybe it's time to throw the towel in and dig deep for a ms2

[pdooley]

Just guessing here, but could the alternator be noisy?
You could try disconnecting it.
Only other thing is make sure your battery/chassis and chassis/engine grounds are good.

[slow_hemi6]

You should do a datalog of these atempted starts and post it up.

[denishark]

Hi.. I have the same problem...

My grounding squeme are how in the manual, I already powered the module with a other battery also, but during cranking goes to offline in TunerStudio.

My module is a V3 board with MS2 with 3.3.2 msextra firmware.

Any solution for these problem ?

Denis

[Rick Finsta]

Pull the ignition fuse and see if it persists. You can do the same for the injectors or any other powered output (fuel pump, O2 sensor, etc.).

See if there is something out there causing the noise.

[denishark]

Hi...

I found the problem in my installation... the injector configuration was wrong, i'm using low impedance injector but don't using resistor, and the PWM configuration was wrong.

Now I configured my PWM to 1ms to open the injector and 30% (My board is V3) for maintain open... and the resets is over.

Denis

[Rick Finsta]

Sounds great! Make sure you follow the injector opening time tuning method found in the manual now that you can get the car to idle to dial in the injector characteristics.