Throttle follower w/ engine run-time?
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On The Tree
Joined: Feb 2002
Posts: 111
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From: Plano, TX
Throttle follower w/ engine run-time? I'm encountering an odd issue with idle stability when decelerating and disengaging the clutch. When coming to a stop, pressing the clutch and braking will cause the tach will severely drop (to around 200-400 RPM) and attempt to recover an idle by surging the IAC. After several minutes of runtime, this problem seems to go away and the RPMs will drop to idle without surge.
What's strange is this surging idle event will only happen within the first few minutes of engine runtime, even if the engine is warm. This gets me every time I make a stop (at the bank or store), restart the warm engine, and have to modulate the throttle to hold an idle after coming to a stop. After several minutes of runtime, I have no problem with maintaining an idle after coming to a stop. What gives?
What's strange is this surging idle event will only happen within the first few minutes of engine runtime, even if the engine is warm. This gets me every time I make a stop (at the bank or store), restart the warm engine, and have to modulate the throttle to hold an idle after coming to a stop. After several minutes of runtime, I have no problem with maintaining an idle after coming to a stop. What gives?
Re: Throttle follower w/ engine run-time? It only happens at first because the the system is still in open loop mode. You need to scale the volumetric efficiency to solve this problem. Some people scale the main VE by 60%.
On The Tree
Joined: May 2002
Posts: 191
Likes: 0
From: Phoenix, Az
Re: Throttle follower w/ engine run-time? It could also be tht the PCM is trying to re-learn the idle. Make sure you have power to the PCM when the key is off. There is a fuse for this, but I'm not sure it it only powers the PCM when the key is off.
