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Old 11-07-2010, 10:25 AM   #1
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Default Cold weather warmup troubles

So ive been tuning my car since the cold weather hit. My logic is come spring my tune will be close after an intercooler because in this cooler weather my IAT's sit between 80* and 90* and thats closer than my previous tune that was seeing 130* non intercooled. My hope is to have most of the around town and cruising map pretty close.

Now the ugly part. With temps around 30* the warmup has not been to good. I am seeing 16:1 to 18:1 through the warmup. After it fully warms up it drops to 13.5:1ish which is silky smooth in my car. At this point the IAT is around 80*ish. So I poped my hood to let some cool air in and as the IAT droped the car started to lean right out. I saw about 15.5:1 with the cooling IAT. Drop the hood and go for a quik ride pull in the driveway and bang 13.5:1 again with IAT around 85*.

Is this a coolant related air density adjustment I need to make?

I have played with the warmup wizzard with little effect and values are now much higher than over the summer.
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File Type: xls warmup.xls (1.68 MB, 74 views)
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Old 11-07-2010, 10:46 AM   #2
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IF it were me, I'd completely flatten the AIT-Related Air density table and start over with your tune. You're relying way too heavily on the corrections...

Look at your GAir...air temps go up, enrichments go up (more fuel), air temps go down, enrichments go back down (less fuel)
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Old 11-07-2010, 11:10 AM   #3
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Quote:
Originally Posted by Braineack View Post
Look at your GAir...air temps go up, enrichments go up (more fuel), air temps go down, enrichments go back down (less fuel)
Sorry I'm pretty new to this but isn't that backwards.
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Old 11-07-2010, 12:35 PM   #4
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no, it's not. you are adding fuel as the intake air temps increase. look at your clt-based air density table.
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Old 11-07-2010, 12:58 PM   #5
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Ok, I made a ton of changes in my VE table as well as the clt based air desity table. Went out and it started great and idles much nicer than before. Still a touch lean but I will work all that **** out. No correction until 80* and goes up marginally from there. I'm gonna let it cool and do a complete cold start warmup cycle and log it again. Now i think I understand whats going on.

BTW thanks for the help.
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Old 11-07-2010, 08:43 PM   #6
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Ok im pretty sure I have this all figured out thanks to Brain. She starts right up and idles very nicely most of the way through warm up. I still have to tweak the warmup enrichment's but my AFR's are between 13:1 and 15:1 on warmup and settle to 13.5:1 at full warmup when the cooling fan starts. Idle is very smooth and a huge improvement over this morning. As Brain pointed out the Clt related air density table was really screwing me up. That is the way it was set in the base map and now that I know its more for heatsoak it should not start adjusting fuel until 80*(thats where I set it for now). I will prob change this to an even higher number but works fine now in the cold.

Now my warmup log shows consistent Gair numbers when compared to the airdenfactor file. Before my changes the Clt related air density table was changing the Gair numbers. This was causing it to run lean until my IAT's climbed to 80* or so and dumping in the extra fuel. So now I understand the Clt related air density's purpose. When you park and heatsoak the IAT sensor, it may read 140* but your actually getting much cooler air so the clt related air density fudges the gair to trick the ecu into adding more fueling for the lower temp your actually geting.

Sorry you all probably know this but I just had to write it out.

Last edited by urabus; 11-07-2010 at 08:57 PM.
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