1987 idle setting
Thread Starter
Cruising
Joined: Jul 2006
Posts: 14
Likes: 0
1987 idle setting
Ive just tried to reset the idle on my 1987 after fitting a new IAC valve. I followed the procedure as written in the GM manual, and when i connected things back up, the car was idling at 1400 rpm! So i just turned the screw down again, which defies the point of resetting it to the book really. Should i have left it at 1400 rpm and taken it for a drive to let it "settle"?
Le Mans Master
Joined: Aug 2003
Posts: 9,884
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From: Magnolia Mississippi
St. Jude '03-'04-'05-'06-'07
Don't know if you followed this process, but it works - make sure as your adjusting the idle, you bump the throttle to seat it, sometimes it gets stuck and you don't reall know what the actual adjustment is really at...
1. Warm the engine.
2. Ignition "Off, engine "Off". Jump terminals "A" and "B" of the ALDL together.
3. Turn ignition to "On".
4. Wait 30 seconds, then unplug the IAC connector.
5. Turn the ignition "Off".
6. Remove the ALDL jumper.
7. Start the engine and adjust the minimum air to the specified (desired) rpm.
8. Shut off engine, connect IAC.
9. Ignition "On", adjust TPS voltage.
10. Acclimate the IAC. Some cars have an ignition on/off procedure, but it will happen on all C4s, if you take it, warmed up, for a drive and exceed 40 mph.
Apparently, some year FSMs say to disconnect the EST wire. Most *I* am aware of don't. If the manual says to disconnect the EST, then disconnect it.
1. Warm the engine.
2. Ignition "Off, engine "Off". Jump terminals "A" and "B" of the ALDL together.
3. Turn ignition to "On".
4. Wait 30 seconds, then unplug the IAC connector.
5. Turn the ignition "Off".
6. Remove the ALDL jumper.
7. Start the engine and adjust the minimum air to the specified (desired) rpm.
8. Shut off engine, connect IAC.
9. Ignition "On", adjust TPS voltage.
10. Acclimate the IAC. Some cars have an ignition on/off procedure, but it will happen on all C4s, if you take it, warmed up, for a drive and exceed 40 mph.
Apparently, some year FSMs say to disconnect the EST wire. Most *I* am aware of don't. If the manual says to disconnect the EST, then disconnect it.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by vinnies87
Don't know if you followed this process, but it works - make sure as your adjusting the idle, you bump the throttle to seat it, sometimes it gets stuck and you don't reall know what the actual adjustment is really at...
1. Warm the engine.
2. Ignition "Off, engine "Off". Jump terminals "A" and "B" of the ALDL together.
3. Turn ignition to "On".
4. Wait 30 seconds, then unplug the IAC connector.
5. Turn the ignition "Off".
6. Remove the ALDL jumper.
7. Start the engine and adjust the minimum air to the specified (desired) rpm.
8. Shut off engine, connect IAC.
9. Ignition "On", adjust TPS voltage.
10. Acclimate the IAC. Some cars have an ignition on/off procedure, but it will happen on all C4s, if you take it, warmed up, for a drive and exceed 40 mph.
Apparently, some year FSMs say to disconnect the EST wire. Most *I* am aware of don't. If the manual says to disconnect the EST, then disconnect it.
1. Warm the engine.
2. Ignition "Off, engine "Off". Jump terminals "A" and "B" of the ALDL together.
3. Turn ignition to "On".
4. Wait 30 seconds, then unplug the IAC connector.
5. Turn the ignition "Off".
6. Remove the ALDL jumper.
7. Start the engine and adjust the minimum air to the specified (desired) rpm.
8. Shut off engine, connect IAC.
9. Ignition "On", adjust TPS voltage.
10. Acclimate the IAC. Some cars have an ignition on/off procedure, but it will happen on all C4s, if you take it, warmed up, for a drive and exceed 40 mph.
Apparently, some year FSMs say to disconnect the EST wire. Most *I* am aware of don't. If the manual says to disconnect the EST, then disconnect it.
Pure genius! Well written, concise and precisely in proper order. I couldn't have said it better myself. Maybe just as WELL post #14, but not better.
RACE ON!!!
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Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Originally Posted by cymro
I definately CAN adjust the idle.....if i turn the screw on the throttle linkage, the idle goes up or down.
Is this screw the same thing as "min air adjust"?
Is this screw the same thing as "min air adjust"?
I believe it is possible to turn it in so far, as to out of range of the ECM to compensate or be in control which would bring up the idle speed.(Likewise to low).
HOWEVER, THIS IS NOT what you are trying to accomplish when setting min. air adjustment.
BTW, the idle speed (base etc.)is PROGRAMMED in the chip(prom) and is absolutely correct as CFI has already said.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by cymro
I definately CAN adjust the idle.....if i turn the screw on the throttle linkage, the idle goes up or down.
RACE ON!!!
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Originally Posted by cymro
Leaving crappy icons really does not help me.
Race Director
Joined: Feb 2004
Posts: 12,517
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Originally Posted by cymro
Leaving crappy icons really does not help me.
Thread Starter
Cruising
Joined: Jul 2006
Posts: 14
Likes: 0
Listen guys...the hyjacked thread was mine to start with. Im not debating or disputing any advice that i am GRATEFULLY recieving. All i am saying is that after following the correct procedure my car ends up idling at 1400 rpm. Now that ist right is it?
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Originally Posted by cymro
following the procedure my car ends up idling at 1400 rpm. Now that ist right is it?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by cymro
Listen guys...the hyjacked thread was mine to start with. Im not debating or disputing any advice that i am GRATEFULLY recieving. All i am saying is that after following the correct procedure my car ends up idling at 1400 rpm. Now that ist right is it?
Originally Posted by cymro
I definately CAN adjust the idle.....if i turn the screw on the throttle linkage, the idle goes up or down.
RACE ON!!!
Thread Starter
Cruising
Joined: Jul 2006
Posts: 14
Likes: 0
The vacuum lines are fine....i cant repeat the procedure just now because its the middle of the night here in the uk. I think we are all having differences in terminology..(or i am rather). My GM manual talks of adjusting the idle speed by turning the screw on the linkage on the side of the throttle body....but you guys are calling this the minimum air adjustment...am i correct?
Le Mans Master
Joined: Feb 2005
Posts: 5,146
Likes: 3
From: The Motor City
Originally Posted by cymro
The vacuum lines are fine....i cant repeat the procedure just now because its the middle of the night here in the uk. I think we are all having differences in terminology..(or i am rather). My GM manual talks of adjusting the idle speed by turning the screw on the linkage on the side of the throttle body....but you guys are calling this the minimum air adjustment...am i correct?
It is referred to as: "adjusting min. air" because that is what you are doing, there is no fuel in the throttle body. I must not understand an 87 Throttle Body, "a screw on the linkage side of the throttle body" . Does this mean that the screw you are adjusting is not in a recessed area above the throttle cam?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by cymro
Listen guys...the hyjacked thread was mine to start with. Im not debating or disputing any advice that i am GRATEFULLY recieving. All i am saying is that after following the correct procedure my car ends up idling at 1400 rpm. Now that ist right is it?
Originally Posted by cymro
My GM manual talks of adjusting the idle speed by turning the screw on the linkage on the side of the throttle body....but you guys are calling this the minimum air adjustment...am i correct?
RACE ON!!!
Thread Starter
Cruising
Joined: Jul 2006
Posts: 14
Likes: 0
Its on the drivers side of the throttle body, where the throttle cable is connected. The screw adjusts the position of the discs in the throttle body, or "butterflies" as we tend to call them, in relation to the linkage. Its all well and good these other guys saying this is what your car WILL do...etc. but i did say right at the start what my car IS doing. I cant help it if it doesnt comply with their presumtious ideals.