Idle won't
Thread Starter
Pro
Joined: Jun 2004
Posts: 646
Likes: 0
From: Santee Ca
Idle won't
I asked this question over in scan and tune and recieved no replies so I thought I would try it here.
My '85 idle does not come down immediately. It is a manual and when I shift the RPM's stay up around 2500 when I push the clutch in to shift gears. When I push the clutch in when coming to a stop the same thing happens but the idle will eventually drop back down below 1000 when I come to a complete stop. I noticed the IAC counts are high when this happens and when the car is idleing ok the counts are around the 40-50 range. Is this normail? How can I adjust this? I like to be able to take my foot off the gas and the car start to slow down. I don't think it is the throttle body sticking or anything as this is the second throttle body I have had on the car and they both do it. I have a scan of my car if anyone is willing to look at it for me and give me suggestions.
My '85 idle does not come down immediately. It is a manual and when I shift the RPM's stay up around 2500 when I push the clutch in to shift gears. When I push the clutch in when coming to a stop the same thing happens but the idle will eventually drop back down below 1000 when I come to a complete stop. I noticed the IAC counts are high when this happens and when the car is idleing ok the counts are around the 40-50 range. Is this normail? How can I adjust this? I like to be able to take my foot off the gas and the car start to slow down. I don't think it is the throttle body sticking or anything as this is the second throttle body I have had on the car and they both do it. I have a scan of my car if anyone is willing to look at it for me and give me suggestions.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Well, this will get you ttt again. I would have guessed at dirty throttle body-but you say you've had the same results with 2. How's the cable,
they don't last forever.If you've scanned your IAC counts and it looks like you did-you should know that 1-40 is the spec., I don't know if 50 is to high though.
they don't last forever.If you've scanned your IAC counts and it looks like you did-you should know that 1-40 is the spec., I don't know if 50 is to high though.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
It probably isn't the throttle sticking, because, if anything, that would cause the ECM to close the IAC, and the counts would be lower than at a good idle. With the higher counts, it seems as though the ECM is commanding the higher idle. WHY? My first guess is the ECT sensor. If the ECM thinks the engine is cold, if may be commanding a fast, cold idle. Do a check on you ECT sensor. Also, see what else your FSM has to say on the subject. There are probably trouble shooting charts.
RACE ON!!!
RACE ON!!!
Melting Slicks
Joined: Aug 2003
Posts: 3,394
Likes: 393
From: Lakeville MI
When your on throttle, the IAC will "follow" the throttle position with a bit of delay time. The iac opens when the throttle is opened and closes when the throttle closes, but with a delay. This is normal function.
If the rpm is hanging too high for too long, following closing throttle then you probably have some tps and or throttle stop adjustment issues. If your tps voltage is too high then you will be getting into or staying in throttle following mode even with closed throttle, not good.
First check your tps for 0.54 volts when closed. Also if the throttle stop is over adjusted, the combination of slightly open throttle plates and the iac can result in enough airflow to sustain idle in the range of 2000 rpm or so with 145 IAC counts.
Extra spark advance could also contribute to the problem, so you may want to check timing too.
If the rpm is hanging too high for too long, following closing throttle then you probably have some tps and or throttle stop adjustment issues. If your tps voltage is too high then you will be getting into or staying in throttle following mode even with closed throttle, not good.
First check your tps for 0.54 volts when closed. Also if the throttle stop is over adjusted, the combination of slightly open throttle plates and the iac can result in enough airflow to sustain idle in the range of 2000 rpm or so with 145 IAC counts.
Extra spark advance could also contribute to the problem, so you may want to check timing too.
Thread Starter
Pro
Joined: Jun 2004
Posts: 646
Likes: 0
From: Santee Ca
Originally Posted by tequilaboy
When your on throttle, the IAC will "follow" the throttle position with a bit of delay time. The iac opens when the throttle is opened and closes when the throttle closes, but with a delay. This is normal function.
If the rpm is hanging too high for too long, following closing throttle then you probably have some tps and or throttle stop adjustment issues. If your tps voltage is too high then you will be getting into or staying in throttle following mode even with closed throttle, not good.
First check your tps for 0.54 volts when closed. Also if the throttle stop is over adjusted, the combination of slightly open throttle plates and the iac can result in enough airflow to sustain idle in the range of 2000 rpm or so with 145 IAC counts.
Extra spark advance could also contribute to the problem, so you may want to check timing too.
If the rpm is hanging too high for too long, following closing throttle then you probably have some tps and or throttle stop adjustment issues. If your tps voltage is too high then you will be getting into or staying in throttle following mode even with closed throttle, not good.
First check your tps for 0.54 volts when closed. Also if the throttle stop is over adjusted, the combination of slightly open throttle plates and the iac can result in enough airflow to sustain idle in the range of 2000 rpm or so with 145 IAC counts.
Extra spark advance could also contribute to the problem, so you may want to check timing too.
