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  #1  
Old 04-06-2012, 03:17 AM
goldenhp goldenhp is offline
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Default rpm dropping too fast
i have a classic fast with a manual trans. while im driving when shift it seems my rpm drops rather fast between shifts and when im coming to a stop an go into neutral rpm drops so fast that engines almost stalls sometimes it does. then it surges until its smooths itself out. so question is what tables and setting should be adjusted so i wont have this happen kinda annoying. thanks in advance
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Old 04-06-2012, 08:09 AM
norbs norbs is offline
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1st you need to set your IAC target position so that it is in an acceptable range, I don;t work with manual trans cars much, but on automatics I look for a number around 10 in park. You will have to adjust the idle set screw until you see this number on the throttle body. The next table is in the idle functions menu, called the throttle follower, you need to increase the values in the table so it looks like a mountain, higher numbers on the right of page.
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Old 04-06-2012, 07:59 PM
TurboNova TurboNova is offline
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Norbs covered most of it, the throttle follower is most of the idle droop problem but you have to set the relationship between the idle screwe and the throttle follower. An IAC of 10-20 in neutral. Also look at the idle timing table and make sure it is not all zero..
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Old 04-06-2012, 08:57 PM
norbs norbs is offline
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Here is a typical example, with a properly adjusted IAC at idle motor does not have to open much to be effective to prevent stalls, but each motor is different. If its too high the engine will rev after you release the throttle too long and won;t be comfortable to drive, to low it will stall...
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Last edited by norbs; 04-06-2012 at 09:05 PM.
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Old 04-06-2012, 11:21 PM
TurboNova TurboNova is offline
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Most engines respond better when the IAC settings are 10-20 on the far left of that picture. This gives the IAC the ability to close a little if needed before getting back to the target.
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  #6  
Old 04-07-2012, 04:44 AM
norbs norbs is offline
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Actually that map is from a classic fast and the tps starts around 9% so we never get in that region, but you have a good point, I'll raise it a bit in future tunes. The person I tuned the car does not want any high idle, so we were trying to keep the counts low. On another note if the throttle follower is kept to high it will never let you achieve min idle, but you will see this on your idle rpm menu when the cursor is being forced above the line.


thanks

norb
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Last edited by norbs; 04-07-2012 at 09:06 AM.
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