Is there a way to force a fuel cutoff on engine stop?
Attaching log and project.
Fuel_enrichment_on_engine_stop.emub3 (57.4 KB)
20240601_1906_fuel_enrichemnt_on_engine_stop.emublog3 (311.7 KB)
if it is speed density the PW increases because MAP increases
it’s speed density, but the VE map in that area when engine stopping is flat.
I tried to isolate everything I’m aware of to make it not happen, but failed - maybe there is other (lambda related?) enrichment I need to take care of?
Also in this run engine tried to self start after turning the ignition off (happened few times before to me, that’s why I’m trying to isolate this).
but in speed density the PW is proportional to MAP
If the MAP increases the PW increases.
Then why engine tries to self start after turning off the ignition?
There should be no spark after turning off the ignition key right?
I need to isolate that gremlin, therefore again is there a way to fuel cut i.e. below 1000 RPM?
Currently managed to idle at 1500, which is high, I should get down to 1200, but that later…
EDIT: if I turn ignition key off at the middle of the green squared area, why the PW is increasing? There should be no fuel after turning the key off?
I did another test. For the fuel cut in the Fueling I set it down to 40 (while engine idling at 38).
When I turn the ignition key off, MAP goes above 40 and the fuel PW goes to 0 - no issues with engine trying to self start.
This brings me to the conclusion the ECU still operates for some time after turning the ignition key off cousing such an odd behaviour? Including fuel and spark delivery?
Your wiring must be incorrect as the ignition switch doesn’t turn off the ecu immediately.
Or check and elayed turn off strategy (however this option cuts the fuel immediately)
Wiring should be fine. I built 2 almost exact engines / cars prior to that one (using Classic though), but none had battery positive all time as Black has. Is there a way to log the Ignition Key state? That would make this thing clear at least.
I verified the power delivery at pin G18 and it’s an instant on/off when turning the ignition key on/off. I did try also to change the delayed turn off set to zero “0”, but it has no impact.
Could be some back feed.
turning ingition off cuts the power delivery to inejctors and coils so the engine should dies immediately
Back feed hmmm… Need to think about it, maybe an extra diode by the main relay would help.
Attaching screenshot and log of engine “self start” after turning it off.
You can see on the RPM line 3 bumps up sth the end 600/500/600 RPM.
Anyway if I could log the moment when the IGN key is turned off, that would give the answer. Is it logged / accessible somehow?
Check channel ECU reset.
So I found the culprit. With Black I started using the H-Bridge outputs and these change the state from GND to +12V. I had vacuum solenoid valves connected to these outputs and it caused a back feed to the IGN circuit causing one relay to “hang” for some time after shutting down the ignition. At least that’s what it look like. Engine shut downs properly now and in the log everything disappears as soon as the key is turned off. One proper rectifier diode saves the day 
My bad We learn all life. Thank you for support!
