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Old 04-01-2008, 09:53 PM   #1
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Default Lean every time weather is cold

Is there any solution to this problem? There is at least a factor of 2 difference (afrs + 2 ex 16 instead of 14) every time the air gets cooler.
And no, it's not just the afterstart enrichments, this happens once the car is warm too.
Would the solution be to have 2 or more VE tables to use according to the weather, because that would be a pain in the ***.
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Old 04-01-2008, 09:58 PM   #2
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Originally Posted by 90turboMX5 View Post
Would the solution be to have 2 or more VE tables to use according to the weather, because that would be a pain in the ***.
Sorry that I can't be of help for a proper solution. But the solution that you suggest above is definitely not a good one. You really have to find the source of your problem because assuming that you will always have this offset and running 2 different maps is a bandaid at best and a blown engine at worst.
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Old 04-01-2008, 10:26 PM   #3
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i imagine the megasquirt has an air temp sensor for this very reason... air temp enrichment. set it so it adds fuel when the temp is lower. i'm sure someone has a set of values here.
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Old 04-01-2008, 11:08 PM   #4
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is it lean even after your coolant is up to temp?
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Old 04-01-2008, 11:33 PM   #5
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could be the torque converter.
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Old 04-01-2008, 11:53 PM   #6
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I don't have an issue with this, though when it's cold I tend to let the car warm up a little. You can use IAT based enrichment but it sounds like your IAT sensor isn't reading right because the MS should make corrections based on IAT. You can go into advanced- coolant based density, then set it up for IAT based enrichment and adjust your values in the table accordingly.
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Old 04-02-2008, 07:10 AM   #7
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I notice the car idling at slightly different A/F ratios from day to day, haven't quite worked it out yet. Sometimes it will idle at 12:5.1 or 14.5:1, but then at other times it will behave and sit around 13.3:1. IAT is the GM one.
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Old 04-02-2008, 09:55 AM   #8
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could be the torque converter.





technically you should be richer when it's cold.
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Old 04-02-2008, 10:02 AM   #9
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Originally Posted by cjernigan View Post
I don't have an issue with this, though when it's cold I tend to let the car warm up a little. You can use IAT based enrichment but it sounds like your IAT sensor isn't reading right because the MS should make corrections based on IAT. You can go into advanced- coolant based density, then set it up for IAT based enrichment and adjust your values in the table accordingly.
Do you guys have any tested values for this table?

Thanks
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Old 04-02-2008, 10:03 AM   #10
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technically you should be richer when it's cold.
When it's cold the air is denser = need more fuel
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Old 04-02-2008, 10:12 AM   #11
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Is your IAT sensor reading correctly when it's cold?

Also, when did you get this MSPNP? We issued a bug fix for the sensor calibration values shortly after it came out, but it's possible you may have an early one.
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Old 04-02-2008, 10:21 AM   #12
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Quote:
Originally Posted by Matt Cramer View Post
Is your IAT sensor reading correctly when it's cold?

Also, when did you get this MSPNP? We issued a bug fix for the sensor calibration values shortly after it came out, but it's possible you may have an early one.
Matt,
What is required to update the old values?
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Old 04-02-2008, 10:21 AM   #13
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Quote:
Originally Posted by 90turboMX5 View Post
When it's cold the air is denser = need more fuel

i was assuming warmup enrichments were in place....
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Old 04-02-2008, 11:08 AM   #14
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Quote:
Originally Posted by Matt Cramer View Post
Is your IAT sensor reading correctly when it's cold?

Also, when did you get this MSPNP? We issued a bug fix for the sensor calibration values shortly after it came out, but it's possible you may have an early one.
I got mine in early december 07
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Old 04-02-2008, 12:12 PM   #15
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Ok, that one should have the fix already there. Do you have the AFM removed?

Updating the old values is simply a matter of loading the latest no-AFM firmware.
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Old 04-02-2008, 12:13 PM   #16
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Yea, I'll look at the values from the factory MSPNP and see if they are the same.
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Old 04-02-2008, 12:27 PM   #17
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Actually-- that may very well have the old firmware and config files-- that's when I was on the dyno figuring out the need for a change, and around that time it was implemented, but if you bought in early December it's entirely possible you need to update to the latest firmware and tuning software. It specifically addresses this. It's also assuming you're using our IAT sensor if you've done a MAF delete.
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