Hot IAT, lean AFR

s300 and SManager software questions & answers
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Bubleguy
Posts: 36
Joined: Sun Jan 31, 2010 8:35 pm

Hot IAT, lean AFR

Post by Bubleguy »

Hi team,

i've the same problem as described in those link (hot restart with lean afr)
viewtopic.php?f=19&t=6188&start=0
or
http://www.thirdgen.org/techboard/diy-p ... r-hot.html
or .... many other links

Some said that it is post start problem,some said it is heat soak pb, some said that it is bad tuning... and so on...

To avoid pb with post start and cranking parameter and to reduce investigation field, i decided to try something : let the engine running, under heavy sun, let the engine bay warm up and see...

I dataloged a hot idle when it was fine, i let the engine running and then the pb of lean AFR occured. I dataloged it imediately.
(note:The second datalog just occured 2 or 3 minutes after the first one)

the only thing i see is :
when it is fine : IAT = 47°C
when pb : IAT >48°C

But as "fuel compensation" is 0% from 44°C i don't think pb is related to this parameter.
As i am not enough good with all the parameters i ask you some help.
Here are the datalogs and the slk files.

Do you have any suggestions?
Many thanks

(sry for my bad english)

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Spunkster
Site Admin
Posts: 23878
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Hot IAT, lean AFR

Post by Spunkster »

Try changing your idle speed staionary speed to match the idle speed moving table, or change the moving table to be 900 and the stationary to 840 in the last 2 columns from 177-302. Start there and see what that does.

Also if you look at the battery voltage on the one with the problem you will see it is not as stable as the other datalog. You may also need to slightly change your injector voltage compensation table
Bubleguy
Posts: 36
Joined: Sun Jan 31, 2010 8:35 pm

Re: Hot IAT, lean AFR

Post by Bubleguy »

I put 900 (at stationnay and moving) as you advice. The result is the same. I can do a log if you want. One new step is that i couldn't reproduce the "normal idle", maybe because the weather was very hot today.

Concerning the battery voltage, what would be causing this voltage difference in a timing window of 2-3 minutes?

Concerning the injector voltage compensation, i took it from there : http://www.hondata.com/deatschwerks.html (I have the 1300cc one)

I was told that with my cams, idle was a pain to set up when hot environement, and i was advice to set the idle not under 1000rpm.
What do you thing? do you need another datalog with the changes i made?

Thanks you for the feedback you already gave to me.
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Spunkster
Site Admin
Posts: 23878
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: Hot IAT, lean AFR

Post by Spunkster »

If it was recomended to idle it above 1000 RPM then I would start there as you may not be able to get very good AFR reading with a loping or stumbling idle.
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