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throttle cracker efi

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Old 02-11-2009, 04:35 PM
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I believe the throttle cracker is what needs adjusted for this scenario. I have the idle right where I want it. But when I go to take off, If i'm pulling out of a parking spot or something, I give it the gas and let off and it dies. It's like it just tries to drop the rpms too far after I let off.

Anyone have any tips on how to get this adjusted right?
Old 02-11-2009, 04:38 PM
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I should say. when I let off, the rpms drop, jump up to 1000 and then dies all in one quick motion.
Old 02-11-2009, 04:47 PM
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while i'm on the subject. My idle AFR is commanded around 14.8 and it starts off that way just great. but after a minute or 2 it richens up to abour 13-13.5 I can't seem to figure out why?

Maybe do some VE calibrating?
Old 02-11-2009, 06:11 PM
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Throttle cracker and also look into your throttle follower decay tables in gear
If you want,you can email me your file an I will take a look at it for you
charlie@gowheatley.com
Old 02-11-2009, 07:47 PM
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sent.
Old 02-11-2009, 08:49 PM
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At low speed like you're desribing, throttle follower decay (increase slightly) and decay delay (increase at low rpm) will do wonders.
Old 02-11-2009, 09:16 PM
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Not to thread steal, but why some tuners are near, At all and any first startups by truck idles up normal but then will drop like 300 rpm then just idle back up. Any advice on this? Also if i rev the truck up the rpm drops slowly, would playing with the throttle cracker alow the rpms to drop quicker.

Dustin
Old 02-11-2009, 09:22 PM
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Originally Posted by 2005 Silverado
Not to thread steal, but why some tuners are near, At all and any first startups by truck idles up normal but then will drop like 300 rpm then just idle back up. Any advice on this? Also if i rev the truck up the rpm drops slowly, would playing with the throttle cracker alow the rpms to drop quicker.

Dustin
Check your various startup decay and delay tables. It sounds like it's decaying out a bit too quickly. Is your desired airflow table accurate?
Old 02-12-2009, 12:34 PM
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Originally Posted by dc_justin
Check your various startup decay and delay tables. It sounds like it's decaying out a bit too quickly. Is your desired airflow table accurate?
That's what I was just getting ready to ask. Getting your desired idle airflow numbers in line is fairly important for a good idle.
Old 02-13-2009, 04:18 AM
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Originally Posted by 2005 Silverado
Not to thread steal, but why some tuners are near, At all and any first startups by truck idles up normal but then will drop like 300 rpm then just idle back up. Any advice on this? Also if i rev the truck up the rpm drops slowly, would playing with the throttle cracker alow the rpms to drop quicker.

Dustin
Mine idles fine at startup, but will go real lean 17-18 for a bit and then go where I want it.
I noticed an Engine enrichment Decay rate that leans out the mixture at start up after so many revolutions, but not sure what adjustments to make. I also noticed that the problem I'm having with it wanting to die is only when below operating temps, so I know something needs to be adjusted based on that. Just don't know what. Any ideas on these?
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