rpm
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| posted on 2/9/10 at 06:47 PM |
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cold starting and megasquirt
i've got the car running pretty well when warm at the moment, it picks up from low revs and drives fine, the only slight problem is it takes
2-3 long turnovers when cold to start, warm starts are fine. seeing as it does go ok i don't really want to mess with the map too much, so
what happens if i adjust the required fuel in engine constants? does this affect the whole map or just the starting values?. i realise i can adjust
ase values to get it running up better after starting, do the warm up enrichements work on cranking or after start? What i don't want to do is
mess up the whole tune after spending so long getting it right just for the small annoyance of cranking 2-3 times
thanks for any advice
Roger
expert
ex= a has been
spurt= a drip under pressure
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brianthemagical
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| posted on 2/9/10 at 07:29 PM |
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Don't touch the req fuel as that will alter everything.
Are you runnning ITB's with the injectors away from the head?
Altering the cranking pulse and priming pulse sould be your best option, them warm up enrichment if you have to but don't touch the map.
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GregSL75
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| posted on 2/9/10 at 08:42 PM |
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Cranking pulsewidth would be my first port of call.
2.0 XE on GSXR TBs and Megasquirt
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paulf
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| posted on 2/9/10 at 10:56 PM |
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Its the cranking pulse width and priming pulse that you need to adjust, remember that as long as you save the current MAP then you can always revert
back to it if you find it runs worse.
Paul
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rpm
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| posted on 3/9/10 at 07:27 AM |
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cranking and priming pulse it is then, thanks for the advice i'll go and have a play
expert
ex= a has been
spurt= a drip under pressure
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matt_gsxr
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| posted on 3/9/10 at 11:11 PM |
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Cranking is really the priority I think.
Priming pulse is more to purge air from the system, and any fuel is gone after the first couple of rotations or so.
Worth also checking that you are not getting sync errors while cranking (is you have ms2, ms1 doesn't report these).
The problem with cold-start cranking is that you only get one real chance to try your new settings.
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fatbaldbloke
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| posted on 4/9/10 at 07:06 AM |
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The cranking pulse width is usually a lot more than you would think. Without knowing anything about your engine/map/etc I'd plump for around
20ms...
It's usually about 5 times the pulse width you have at hot idle. If you make sure the flood clear setting is set at about 10% under full
throttle you can always clear it if it's too rich.
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irvined
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| posted on 4/9/10 at 06:49 PM |
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You want the cranking pulse width setting, you will either have two values, a cold value and hot value, and if its when cold, you want to
increase/reduce the colder of the values.
The alternative is you can set it to a table, and adjust it per every 10 degrees or so if you need more fine tuning.
I'd stick to two values, and try very small increases of the cold value. (0.5ms a time)
http://irvined.blogspot.com
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rpm
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| posted on 5/9/10 at 07:06 PM |
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had a play around today and i've now got it starting well from cold the advice from fatbaldbloke was good, i had been too timid in my
previous alterations
expert
ex= a has been
spurt= a drip under pressure
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fatbaldbloke
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| posted on 5/9/10 at 08:46 PM |
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quote:
the advice from fatbaldbloke was good
You're probably about the 20th builder I've helped out with the same problem so it wasn't a complete stab in the dark
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