Cold Idle/Stalling

[g60luke]

Hi,

I have an EXP48 ECU and I have an issue when the car is cold that if you are not SUPER gentle and slowly apply the accelerator it will stall. It starts fine and idles, but when you open the throttle it will cut out. It restarts perfectly every time.
But I may go through this cycle 3-4 times reversing off my drive.
After a minute of running its fine.

It runs perfectly when warm idle/performance/mpg/driveability etc all good

I am guessing that as with most maps the warm running is nailed on the dyno, but cold start/idle requires time/money to setup and the window is always very small as it warms up very quickly.


My question is should it be the Water Temp Compensation Map I should adjust since it may be a little weak, and opening the throttle is throwing extra air in and there is not enough fuel there to idle?
Or do I need to adjust the throttle pump effect?

Cheers
Luke

[stevieturbo]

Throttle pump is generally only for fast throttle openings and will only last a few milliseconds.

So I'd be inclined to leave that alone and try coolant temp compensations first.

And yes, just add some fuel. Warmup only lasts a very short time, so dont be concerned with trying to target any specific or lean AFR's

Target getting the engine to do what you want, ie run properly.

[g60luke]

Thanks for the comments. Will try to adjust the water comp table and go from there

Will update when done...

Whats your feelings on DTAs comments of using the start/turns map instead...?

Cheers
Luke

[stevieturbo]

I only really noticed it recently. I can see how it will work, but again, I still think that a purely temperature based would still be required, as some cars have longer warmups than others.

Again, with all of these things it's just a lot of trial and error. But as always, make sure it starts well when warm, and then drop back and start adding fuel when cold as required
Warm settings and tuning must always be good first.

[g60luke]

I only really noticed it recently. I can see how it will work, but again, I still think that a purely temperature based would still be required, as some cars have longer warmups than others.

Again, with all of these things it's just a lot of trial and error. But as always, make sure it starts well when warm, and then drop back and start adding fuel when cold as required
Warm settings and tuning must always be good first.

I agree with you since engine turns count can vary dramatically from tickover to driving hence timings will be random.
I think the temp based is needed for sure.

It starts/runs perfectly when warm so have a good base to start, just cold an issue.
I guess its because the dyno mappers nail warm running whilst on the dyno, and staring/restarting can be nailed. Cold starts/idles have such a small window that they are poorly mapped in this region.

No biggie like you said since I can trial and error in the cold now

Cheers for the help
Luke