Poor idle when radiator fan comes on?
12-12-2007, 12:41 PM
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Poor idle when radiator fan comes on? I have an 08 automatic Corvette. What would cause idle misfire when the radiator fan comes on about 50% or more?
12-12-2007, 03:58 PM
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The fan presumably adds load but maybe the fan coming on,
is only indicative of an even higher load (A/C) or elevated
engine temps. The engine may still be within the same trim
cell but now it's at a MAP-point that is different and may not
like the trimmed mixture, or may not even like to idle as clean
at stoich.
Might try looking at how much higher MAP goes and whether
the fan itself is to blame, or if it's just a telltale for something
else. Expect there are airflow adders for fan, but you might
look for anything that lets you bump spark (more, or less?)
based on fan and other accessory loads as may be appropriate.
I've never looked at anything newer than LS1/LQ9/LS6 myself
so this is all I can suggest.
is only indicative of an even higher load (A/C) or elevated
engine temps. The engine may still be within the same trim
cell but now it's at a MAP-point that is different and may not
like the trimmed mixture, or may not even like to idle as clean
at stoich.
Might try looking at how much higher MAP goes and whether
the fan itself is to blame, or if it's just a telltale for something
else. Expect there are airflow adders for fan, but you might
look for anything that lets you bump spark (more, or less?)
based on fan and other accessory loads as may be appropriate.
I've never looked at anything newer than LS1/LQ9/LS6 myself
so this is all I can suggest.
12-12-2007, 04:19 PM
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The fan presumably adds load but maybe the fan coming on,
is only indicative of an even higher load (A/C) or elevated
engine temps. The engine may still be within the same trim
cell but now it's at a MAP-point that is different and may not
like the trimmed mixture, or may not even like to idle as clean
at stoich.
Might try looking at how much higher MAP goes and whether
the fan itself is to blame, or if it's just a telltale for something
else. Expect there are airflow adders for fan, but you might
look for anything that lets you bump spark (more, or less?)
based on fan and other accessory loads as may be appropriate.
I've never looked at anything newer than LS1/LQ9/LS6 myself
so this is all I can suggest.
is only indicative of an even higher load (A/C) or elevated
engine temps. The engine may still be within the same trim
cell but now it's at a MAP-point that is different and may not
like the trimmed mixture, or may not even like to idle as clean
at stoich.
Might try looking at how much higher MAP goes and whether
the fan itself is to blame, or if it's just a telltale for something
else. Expect there are airflow adders for fan, but you might
look for anything that lets you bump spark (more, or less?)
based on fan and other accessory loads as may be appropriate.
I've never looked at anything newer than LS1/LQ9/LS6 myself
so this is all I can suggest.
