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cosworth mixture screw

Old 17-01-2009, 03:26 PM
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purplemonster
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Default cosworth mixture screw

hi
my little puma just squeezed through the mot ,the mixture was very high 4.9%
so i turned it down ,so it passed the mot but i went to turn it back up and wouldnt adjust?
then my co went to 7% and is stuck there now

so im looking for another ecu

or

information so that i can change the pot in my ecu ?
so has anybody ever done this ?
and what spec is the pot in the ecu ?

any help would be appriciated

thanks
Old 17-01-2009, 04:23 PM
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wes
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Assuming you have a Weber Marelli L1 / L6 / L8 ecu, the CO pot only has 2 turns of + or - adjustment from its zero setting, if you turn it more than that it doesn't do anything. To get back to this setting, turn the screw 5 times in either direction, then turn it the opposite way 2 turns exactley, you now have upto 2 turns of adjustment in either direction.
Old 17-01-2009, 04:26 PM
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its a L6


thanks for that
sounds a bit odd but ill give it a go ?

will i then get a reading if i measure the resistance?
or isit not possible to measure it?

Last edited by purplemonster; 17-01-2009 at 04:28 PM.
Old 17-01-2009, 04:28 PM
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so if that screw just turns and turns that dose not mean its broken then ?

is there no stop at all for the screw then

thanks again
Old 17-01-2009, 06:11 PM
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Originally Posted by purplemonster
so if that screw just turns and turns that dose not mean its broken then ?

is there no stop at all for the screw then
That is correct, it will turn for as long as you can turn it, there is no stop for it. But it will only change the CO settings for upto 2 turns from zero, after that it wont adjust any more.
Old 19-01-2009, 06:52 PM
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just to clarify thats 5 complete 360 degree turns either way then 2 complete 360 degree turns the other way

cheers
Old 22-01-2009, 08:23 PM
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tried this and hasnt worked ,tried it a few ways and nothing

?
Old 04-04-2014, 10:03 PM
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Think my cos has this issue, I'm stuck at 10%. Should we be turning the screw 5 times while the engine is on or off?
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