Author Topic: Car dies in cold afterstart  (Read 5007 times)

Offline wazzu70

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Car dies in cold afterstart
« on: October 15, 2013, 12:13:31 am »
My car will die when cold after starting. The car starts fine, but it will not stay running even though the IAC is in its completely open state. If I keep my foot on the throttle for a few seconds, everything works great and it idles nicely.

I am not sure which parameters to mess with and in what direction to move them. Since the car dies pretty much right away I can't get much data.

I figure someone here will know off the top of their head where I should start modifying. Im thinking its fuel related since that is what the warmup tables control. The question is, am I too rich or too lean if that is the case?

My EGO sensor is not warm enough to get a read, so thats not helpful!

Thanks!
BMW E30 M42 project

Offline mattias

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Re: Car dies in cold afterstart
« Reply #1 on: October 15, 2013, 07:06:06 am »
"IAC in completely open state" does not mean that it is actually open. There is a certain operating range for the dutycycle used to control the valve,  and if you go outside that range the valve can go into a default open mode or closed.
Try what dutycycle gets you a very high idle while hot, and use that as the maximum.

Generally the best advice can be given if you also present a config, or screenshot of your actual settings that go with the issue you're having (cranking, afterstart, injector settings and associated tables). With the report tool built into VemsTune, that should be the easy part.

Offline wazzu70

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Re: Car dies in cold afterstart
« Reply #2 on: October 15, 2013, 07:30:57 am »
Mattias, I will get some screen shots of my settings.

Also, the IAC fully opened is 60% duty on my engine, any value higher than this the door opens more past the opening with 0 effect.

How many cycles for cold start is a good starting point? Right now its at the default 40 cycles, which seems like its really short now that I think about it.
BMW E30 M42 project

Offline mattias

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Re: Car dies in cold afterstart
« Reply #3 on: October 15, 2013, 07:35:15 pm »
Add a "0" on that and you're close.

Offline wazzu70

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Re: Car dies in cold afterstart
« Reply #4 on: October 17, 2013, 10:53:31 pm »
That did the trick! 40 cycles was not much at all :)
BMW E30 M42 project