Megasquirt Idle problem
Discussion
My very helpful mechanic adjusted the idle screw on my plenum (was idling around 1200 at all times) whilst in for a few niggles and as a result the whole idle is messed up now.
It won't idle properly when cold and and sometimes almost stalls when clutched in going up to junctions etc.
Is there a way to reset the idle to what it was? I've wound the screw out an bit but can't get it happy again.
Am guessing the map sites in MS are conflicting with the extra/less air being drawn in to what it was - being that my MS is running purely in open loop mode - ie not responding to lambda.
debaron said:
My very helpful mechanic adjusted the idle screw on my plenum (was idling around 1200 at all times) whilst in for a few niggles and as a result the whole idle is messed up now.
It won't idle properly when cold and and sometimes almost stalls when clutched in going up to junctions etc.
Is there a way to reset the idle to what it was? I've wound the screw out an bit but can't get it happy again.
Am guessing the map sites in MS are conflicting with the extra/less air being drawn in to what it was - being that my MS is running purely in open loop mode - ie not responding to lambda.
You should change the idle on the MS ,adjusting the screw on the plenum could knock the TPS out so the whole map could be out .It won't idle properly when cold and and sometimes almost stalls when clutched in going up to junctions etc.
Is there a way to reset the idle to what it was? I've wound the screw out an bit but can't get it happy again.
Am guessing the map sites in MS are conflicting with the extra/less air being drawn in to what it was - being that my MS is running purely in open loop mode - ie not responding to lambda.
SILICONEKID343HP said:
You should change the idle on the MS ,adjusting the screw on the plenum could knock the TPS out so the whole map could be out .
Yep that's exactly what I think has happened Daz. I don't think my guy knew it would upset the whole map.Any way to get it back? Trial and error I suppose?!
Sardonicus said:
< This
adjusting the idle bypass screw does not affect the TPS settings
I presume this is the screw that's been adjusted and not the butterfly stop screw? 
Cheers Simon,
adjusting the idle bypass screw does not affect the TPS settings
I presume this is the screw that's been adjusted and not the butterfly stop screw? 
But if the ECU runs in open loop mode at all times as mine does, any extra air entering the engine after the air temp sensor (mine where the old AFM was) would be at odds with the VE table or not?
debaron said:
Cheers Simon,
But if the ECU runs in open loop mode at all times as mine does, any extra air entering the engine after the air temp sensor (mine where the old AFM was) would be at odds with the VE table or not?
Yes but altering the revs by 200/300 RPM should not affect the VE table too much if the figures are nicely smoothed/linear ...... but you may have moved onto a couple of lean cells on your table which may not have been mapped if your engine was not using them pre idle adjustment & hence the stalling But if the ECU runs in open loop mode at all times as mine does, any extra air entering the engine after the air temp sensor (mine where the old AFM was) would be at odds with the VE table or not?
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