Motronic gurus needed!

[Toby_Unna]

i'm converting from motronic to Megasquirt fueling plus motronic spark, to get me going before sorting out the full MSns or whatever it's called!

I obviously need to retain a lot of the motronic engine loom and the ecu, but i'd like to remove some of the surplus wiring, hopefully without losing the ability to make sparks

So does anyone know which sensors the ECU uses to calculate ignition timing/advance.

I know the crank speed/pos sensor is needed, which is wired direct to ecu

things i'm not sure about:
throttle closed/wide open signal
coolant temp
air inlet temp from AFM
other sensors I've forgotten.

From the motronic diagram in the haynes it looks like i can remove the injector wiring, fuel pump relay with all wiring and the main AFM unit.

[Brianmoooore]

I was told once, on a LPG forum, that the AFM has some control over sparks timing, but have never checked it out.
Similar things to what you are doing are done when building a LPG only car, as this has it's own stand alone Fueling ECU, but needs to retain the Motronic sparks.

[Toby_Unna]

Thanks Brian. just removed the loom so now i can take away the obvious stuff and think about the rest.

Hopefully Mark/Ant can answer the AFM thing, i think at some point Mark was running with MS + motronic spark, hopefully minus the AFM?

[Ant]

coolant and intake temp, plus the load signal are required to get the 3D mapped motronic to work as intended


the IAT in the AFM has a trim function but only 1 degree either way on cranking from what I recall, ditch that fella

removal of the AFM takes the load signal away so the motronic reverts to a 2D setup with rpm as its only referance point

soloution is to use the TPS output from your MSnS and feed that into the AFM connector so the 0-5V signal replicates the afm output for the 3D map

its not perfection, but @ 1/2 throttle the AFM would be 1/2 open so you can see where I'm going with this

the idle/wot switch is surplus Toby, if you wanted you could add a microswitch on the linkage( as Len did ) to trigger the idle map for ignition and kick the ICV into life again.

WOT is not required, you wont need the extra advance , in fact best without M8

HTH

if not catch me on MSN dude