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Open loop AFR on cold start

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Old 08-27-2013, 08:23 AM
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Default Open loop AFR on cold start

It seems that when I tune the car with the fuel trims and get my VE around idle really close, plus or minus 5%, the car is lean on cold start up. The way around it that I have found is to play with the open loop equation table in these KPA/RPM areas to richen it back up, so that when it warms up and goes into closed loop all is good. It seems to be working OK but just wondering if there is something I am missing.
Old 08-27-2013, 10:51 AM
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Did you set the open loop eq table all to 1.0 for tuning? If you did, you would need to put it back when done.

If you did put it back, and it is still lean during cold start, they yeah you would have to add fuel via the OL EQ table.
Old 08-27-2013, 11:39 AM
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Cold start AFR ought to be set by "what it likes", not
a wideband number. Stoich (indicated) may not be a
valid target, esp. if fuel atomization is poor, AIR pump
is on, whatever. Go by the vacuum reading (MAP
inverse) as your indicator-of-happiness as you mess
around.
Old 08-27-2013, 11:40 AM
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Originally Posted by Bowtie316
Did you set the open loop eq table all to 1.0 for tuning? If you did, you would need to put it back when done.

If you did put it back, and it is still lean during cold start, they yeah you would have to add fuel via the OL EQ table.
Yes I did have it at 1.0 for tuning. Put the table back to stock and was still getting a lean cold start. So it sounds like I am doing it right then. Thanks
Old 08-27-2013, 11:43 AM
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Originally Posted by jimmyblue
Cold start AFR ought to be set by "what it likes", not
a wideband number. Stoich (indicated) may not be a
valid target, esp. if fuel atomization is poor, AIR pump
is on, whatever. Go by the vacuum reading (MAP
inverse) as your indicator-of-happiness as you mess
around.
Thats kind of what I have been doing, watching MAP and LTIT. The car was really lean to the point it would almost die after a real cold start.



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