Cold-start Dilemma

[B1ack_Mi16 67]

I have a little dilemma.

 

The other day the 2.3 wouldn't run on all cylinders due to too much fuel and sooting down the plugs.

This due to too much fuel on warm-up enrichment I think. AFR meter occotionally showed AFR's of 9, but more regulary around 10-11 mark.

 

I changed the plugs for new ones yesterday and now it runds fine again.

I also ran it to the coolant was 90 degrees C, and sorted out the hot-idle at pretty much spot on 1000rpm with AFR between 14 - 15.

 

This morning when everything was back to cold I was going to fix the cold-start enrichement map.

Fired her up and it was like AFR 10 again. Reduced fuelling at 0 deg C and tried again.

 

It won't run on 12-13, seem to need more fuel, but I don't wanna give her more than 13.5 under warm up.

When coolant is 30-60 deg it idles fine on 13.5 AFR.

 

So it's mostly -10 to +10 deg C that's the problem.

 

I'm starting to think I'm better off just having my foot on the throttle in the beginning just to wait for it to warm up.

 

I know I can open up the throttles and give it more air, but then it will idle at 12-1300rpm when hot, and that sounds really silly too.

 

Any ideas what AFR's that's safe to use and won't give bore-wash?

 

I'm running an Emerald M3D btw..

Edited January 11, 2007 by B1ack_Mi16

[Robsbc 0 1 Cars]

I have a little dilemma.

 

The other day the 2.3 wouldn't run on all cylinders due to too much fuel and sooting down the plugs.

This due to too much fuel on warm-up enrichment I think. AFR meter occotionally showed AFR's of 9, but more regulary around 10-11 mark.

 

I changed the plugs for new ones yesterday and now it runds fine again.

I also ran it to the coolant was 90 degrees C, and sorted out the hot-idle at pretty much spot on 1000rpm with AFR between 14 - 15.

 

This morning when everything was back to cold I was going to fix the cold-start enrichement map.

Fired her up and it was like AFR 10 again. Reduced fuelling at 0 deg C and tried again.

 

It won't run on 12-13, seem to need more fuel, but I don't wanna give her more than 13.5 under warm up.

When coolant is 30-60 deg it idles fine on 13.5 AFR.

 

So it's mostly -10 to +10 deg C that's the problem.

 

I'm starting to think I'm better off just having my foot on the throttle in the beginning just to wait for it to warm up.

 

I know I can open up the throttles and give it more air, but then it will idle at 12-1300rpm when hot, and that sounds really silly too.

 

Any ideas what AFR's that's safe to use and won't give bore-wash?

 

I'm running an Emerald M3D btw..

 

-10 to +10 deg C was the area I had trouble starting from a cold start...Burn time sare much slower at these temps.

 

I can get mine to fire cleanly from -3degrees and then idle around 700rpm within 5 seconds. I use the throttle to hold the revs in those 5 seconds. By a min it's up too 900rpm. Fully warm it's just over a 1000rpm.

 

You need to play around with cranking enrichment to get the car to fire without any misfire. Once started the M3D ECU halves the correction used for the cranking enrichment and then decays over the next 5 seconds. Also after firing up this halved correction percentage is added onto the fuel against coolant temp correction. If the car dies as soon as you hit the throttle you have 2 options you add more fuel in the fuel against coolant temp correction or maybe a bit more on cranking enrichment. If you go too far one way in the corrections you have to reduce the other correction and vice versa.

 

Also have you switched on the idle speed controller fucntion? This advances the ignitions and helps with idle speed escpecially when cold.

 

Also I found too many cold starts on cars with tb's without a proper warm up fouls the plugs easy.

Edited January 11, 2007 by Robsbc

[B1ack_Mi16 67]

-10 to +10 deg C was the area I had trouble starting from a cold start...Burn time sare much slower at these temps.

 

I can get mine to fire cleanly from -3degrees and then idle around 700rpm within 5 seconds. I use the throttle to hold the revs in those 5 seconds. By a min it's up too 900rpm. Fully warm it's just over a 1000rpm.

 

You need to play around with cranking enrichment to get the car to fire without any misfire. Once started the M3D ECU halves the correction used for the cranking enrichment and then decays over the next 5 seconds. Also after firing up this halved correction percentage is added onto the fuel against coolant temp correction. If the car dies as soon as you hit the throttle you have 2 options you add more fuel in the fuel against coolant temp correction or maybe a bit more on cranking enrichment. If you go too far one way in the corrections you have to reduce the other correction and vice versa.

 

Also have you switched on the idle speed controller fucntion? This advances the ignitions and helps with idle speed escpecially when cold.

 

Also I found too many cold starts on cars with tb's without a proper warm up fouls the plugs easy.

 

As you say, it's possible to make it run, but the problem is that it requires AFR's around 10 area to really keep running, and I'm fairly sure this is in bore-wash territorium and don't like it at all.

 

Do you have an AFR meter in your car to see how rich your's running?

I've been removing lots of enrichment to get it up to around 13 area.

 

The whole problem is that the engine really needs extra air when cold, but whit no cold-start valve this is not easy unless you just keep the foot on the throttle.

 

I have not enabled the idle speed correction, I find the engine actually idles more uneven using this. Engine note also varies quite a bit with different ignition values.

 

Adding a idle-valve and using lots of t-pieces would probably be the best solution, but I don't wanna mess up my engine with such additional crap.

[welshpug 1,657]

choke cable?

[Robsbc 0 1 Cars]

No AFR meter on the 16V or when I had the 8v on tb's.

 

I never really let the car idle from cold I try to drive and warm the car up so avoiding the idle load/speed site.

 

Your only way is to fit an IACV to get the extra air needed...

Edited January 11, 2007 by Robsbc

[Sam 4]

Get an old style mini choke cable, you can turn and lock it and link this to the throttle?

[B1ack_Mi16 67]

Get an old style mini choke cable, you can turn and lock it and link this to the throttle?

 

Will just make the bay look more messy.

 

But afaik I need to use the foot on the throttle then, and that's it.

At least as long as I wanna have a fairly low idle when hot.

 

Just wanted to know if anyone had managed to make cold starts work perfect without touching throttle, and still not have too high idle on hot engine.

[Sam 4]

1 cable?! You buffty! Just get it in - either that or whine about it. Mine was the same (like a dog on cold mornings) and I just got in and drove it - it never stalled. Without an ICV its just never going to happen.

[Robsbc 0 1 Cars]

Well said Sam...!

 

What do you expect the injectors aren't even in the optimized position for cold starting/idling (should be next to the inlet ports).

Edited January 12, 2007 by Robsbc

[petert 587]

Silly cold climates. Move somewhere warmer! Letting it idle at between 11 and 12 AFR should not be a problem for that brief time. I'd be aiming for 12.5 to 13 max. when hot. Over here in Oz., the ambient air temp is rarely a problem, and enough air bleeds around the flaps/shafts to get 800 cold, then 1000 rpm hot.

 

Setting up cold starts maps are a pain, as you only get one go at it each day. It once took me fortnight to get my Mi16 correct!

[Robsbc 0 1 Cars]

Setting up cold starts maps are a pain, as you only get one go at it each day. It once took me fortnight to get my Mi16 correct!

 

I know the feeling Peter

[B1ack_Mi16 67]

What do you expect the injectors aren't even in the optimized position for cold starting/idling (should be next to the inlet ports).

 

I'm not expecting anything really, I just wanted to know if it was possible to make it work nice both when cold and hot, or if I need to keep the throttle open in the beginning. Nothing more than that..

 

Was -5C air and coolant temp yesterday, and it will only be used in spring / summer / autumn anyway so guess the temps should be a bit higher then, at least in a while when the global warming has gone a little longer

[B1ack_Mi16 67]

Just a little movie of the warm-idle.

http://cortex.fa-s.ntnu.no/~kristian/205gt...rs/Tomgang.divx

 

I'm very pleased by how steady it idles.

[snillet 1]

As mentioned earlier if your ECU can increase advance after cold starts that makes everythine better, since the fuel burns painfully slow at low temps advancing the ignition after cold start stabilizes the engine a LOT when cold.

 

For me it is extra painful since i´m driving on E85 (85% ethanol), that burns like....sloooow when it´s cold .....

But an added 15( !!!!! ) degrees at -15degr C and rolling off up til 40 degrees coolanttemp linearly makes it smooth as a newly shaved butt to drive cold.

[Anthony 1,003]

I'm wondering if you can do this another way - adjust the throttle stop so as to open the throttles slightly to improve cold start, and reducing the warm ignition advance (or lean the mixture right off possibly?) when warm to keep the warm idle speed down?

 

Oh, and have you checked the throttle bodies are in balance? I've found that when they're even slightly out of balance cold starts are hopeless, but usually idle OK when warm unless they're miles out.

[B1ack_Mi16 67]

Old post this.

 

The cold start problem is only a problem if I adjust the throttle stop to make it idle at 1000rpm when hot, which is pretty low for the camshaft spec I would imagine.

 

Anyway I started the little bastard yesterday in -8 degrees C, and it was not easy, but started after a few tries.

After 30 secs it'll idle ok so at the moment the engine is as good as I think it's realistic to expect from it's spec.