Very low idle on startup, sometimes dies

[crosso]

So it turns out that there was nothing wrong at all, this problem naturally disappeared over 3 weeks or so and was good for the last 2 weeks, then today after having the battery disconnected for an hour, the ECU reset, and voila the very low idle/stalling is back.
So I'm just going to assume it was the ECU learning to idle properly

[mela!]

If it comes back again, my money is on Alternator, this sounds EXACTLY like mine when I first test drove it :l

[phi-tec]

haha i think crosso is right

[payaya]

Its not your battery or alternator!!

If it's your alternator your car will stall and you wont be able to restart it!

When you first turn your car on in the morning do your revs go to 1500rpm and grdually as your car gets warm it goes down to idle speed which is 750rpm (needle should be half way between 0-1000rpm not 3/4)

If it does do the above and then starts to drop in rpm and stall at warm temp then look only at your idle speed controller.

Or does rpm just go to warm idle speed (750rpm) straight away when cold starting? Look at your idle speed controller.

When engine is warm, if you put the car in neatrul or park, do you rpm shoot up past 1000rpm? Look at your idle speed controller!

When you put your AC on does your revs rise or fall? If fall check your idle speed controller!!

It's not your battery alternator as it has nothing to do with base idle!!

[MADFTO]

Crosso, in my opinion, you're on the money.

I've experienced this every time I don't run my car for a while. I've got a parasitic drain that I need to resolve so I face this more often than not.
I've got a lightened flywheel which exacerbates the problem.

If I remember correctly, the ECU does some sort of hunting in the initial learning phase, I don't know what it's exactly doing but my idle floats around.
Remember that FTOs are an import and the base map without adaptation would be built for 100RON fuel.

I usually let the car run for five minutes after I've fired her up after an ECU reset to let it do whatever it needs to do to establish a base map for 98RON that we have. It might not be necessary to let her idle for that long, but I presume the ECU will be slowly advancing the timing to see what's possible with the fuel it's got. When it drops to 400 RPM I suspect its detected a knock and drops back to safety by what I suspect is a fuel cut, but because you're running low rpm, it ends up in a stall situation.
Before I got the lighter flywheel, the inertia from the flywheel would allow the engine to fire back up again.

Side note/conjecture: If you're pedantic about getting the best performance when swapping to a higher RON fuel, an ECU reset might clear any learnt behaviour. Mind you, I'd expect the ECU eventually learn by advancing the timing further every so often, but the ECU reset will probably speed up the process.

The 6100 RPM is a hard limit when the engine is in startup mode, MIVEC also does not engage during this mode (If you've ever tried punching out of a corner a minute after you've started the car and hit this limiter, you'll know what I mean )

This startup mode I believe is also known as limp mode.

[payaya]

I cant say I have had my car ever idle funny after an ECU reset. Screwed up shifting but never anything engine related.

[Technikhaus]

I had mine stalling on idle for the first day or two after an ecu reset

[Bennoz]

Haltech controlled idle ftw :Cheers: