Help with hot starts
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TECH Fanatic
Joined: Feb 2002
Posts: 1,089
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From: New Jersey
Help with hot starts Well, were in a Heat wave up here, meaning anything over 90 
but anyway, my hot starts are driving me nukin futs! I have some data I can post as a reference if that helps?
11.56 GPS at idle.
IAC counts at 42-48 idle.
19-20 hg at idle.
20 degrees of timing at idle.
All is well on cold starts, I just hit the key and when the idle goes a bit low 1,100 for cold start, I just touch the gas pedle and drop it in gear with no problems, hot starts are a rolling surging mess and even worse now that I changed to a larger Y pipe
. ANY input to help me with my IAC/VE tables would be highly appritiated.
Joe.
but anyway, my hot starts are driving me nukin futs! I have some data I can post as a reference if that helps?11.56 GPS at idle.
IAC counts at 42-48 idle.
19-20 hg at idle.
20 degrees of timing at idle.
All is well on cold starts, I just hit the key and when the idle goes a bit low 1,100 for cold start, I just touch the gas pedle and drop it in gear with no problems, hot starts are a rolling surging mess and even worse now that I changed to a larger Y pipe
. ANY input to help me with my IAC/VE tables would be highly appritiated.Joe.
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Joined: Nov 2001
Posts: 2,593
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From: TEXAS
Re: Help with hot starts This is something I saved from a post along time ago, when I was dealing with my cam:
Idle Speed: You can raise this up a little bit to help with a cammed car. The problem is on automatics if you raise it too high the car will lurch when put into drive, or auto roll at 25 mph. With your cam, you should not need to go much higher than the stock RPM.
IAC Park Position: This table directly effects the IAC (the little servo in your TB that controls the amount of air into your engine with the TB closed). If you look at the table, you'll notice that for the colder temperatures the IAC position numbers are much higher than for the hotter ones. This is why your car starts like a dream on a cold day, but idles like crap on a hot one.
Change all cells for temperatures 20 deg C and up to 21. This should take care of your problem. If the car starts to erroneously high idle, then reduce this number until a happy number between idle and operation is found.
Idle Air In Gear: It is the same deal with this table, lots of air when cold, very little when hot. Multiplying the table by 130% should do the trick. Again, if the car starts to autoroll at 25 mph and the RPM's won't drop to a normal place, reduce this table in small steps until a happy medium is found.
IAC Park Position: This table directly effects the IAC (the little servo in your TB that controls the amount of air into your engine with the TB closed). If you look at the table, you'll notice that for the colder temperatures the IAC position numbers are much higher than for the hotter ones. This is why your car starts like a dream on a cold day, but idles like crap on a hot one.
Change all cells for temperatures 20 deg C and up to 21. This should take care of your problem. If the car starts to erroneously high idle, then reduce this number until a happy number between idle and operation is found.
Idle Air In Gear: It is the same deal with this table, lots of air when cold, very little when hot. Multiplying the table by 130% should do the trick. Again, if the car starts to autoroll at 25 mph and the RPM's won't drop to a normal place, reduce this table in small steps until a happy medium is found.
Re: Help with hot starts
yah the ve trick seems to work well.
from 1200 and under reduce by 60%
from 1200 and under reduce by 60%
I think you should start by multiplying by 80% and work you way down from there if needed.
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Re: Help with hot starts Main.
Watch your injector pulsewidths before / after doing the VE table mod. I saw them drop from over 9 msec at idle down to ~4, just by scaling the VE table. Oh, and do it on values 1200 and below. The surging usually goes away once you get above 1500.
-Andrew
Watch your injector pulsewidths before / after doing the VE table mod. I saw them drop from over 9 msec at idle down to ~4, just by scaling the VE table. Oh, and do it on values 1200 and below. The surging usually goes away once you get above 1500.
-Andrew
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Verdad Gallardo Re: Help with hot starts I multiplied the table by 80% and it is about 85% better. Just a little bit of surge for about 5 seconds now. I'm going to try another 10% and that should do it. Thanks for the info!
Re: Help with hot starts I just raised my idle timing to 24 degrees on a few tables and idles at 850 rpm perfect hot/cold.I do have a smaller Cam,but it might help you out.