? about IACV and setting idle
12-05-2004, 12:39 PM
#1
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Join Date: Sep 2004
Posts: 70
? about IACV and setting idle
I've having problems with a high idle on my '95, so I cleaned the throttle body and then took the IACV out, but couldn't figure out what to clean. The internal moving parts are completely enclosed and impossible to see. Is there some part I'm supposed to dissasemble? I tried to separate the large body from the smaller round metal body, but they wouldn't come apart.
The next thing I would like to know is what is the factory shop manual method for setting the idle. This page's "how-to" section says to adjust the idle using the set screw on the throttle body, but a couple other pages I found on the web say to adjust the idle with the adj. screw on the IACV. Which one is right? I had to back my set screw all the way out to get the idle down the 700rpm, and this makes me suspicious.
I also found a couple comments that high or irratic idle could be caused by a problem with the EGR valve. Does anyone know how I might diagnose the EGR valve?
Thanks,
GregS
'95 GLE, 118k
The next thing I would like to know is what is the factory shop manual method for setting the idle. This page's "how-to" section says to adjust the idle using the set screw on the throttle body, but a couple other pages I found on the web say to adjust the idle with the adj. screw on the IACV. Which one is right? I had to back my set screw all the way out to get the idle down the 700rpm, and this makes me suspicious.
I also found a couple comments that high or irratic idle could be caused by a problem with the EGR valve. Does anyone know how I might diagnose the EGR valve?
Thanks,
GregS
'95 GLE, 118k
12-05-2004, 04:12 PM
#3
Member who somehow became The President of The SE-L Club
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Default idle speed is set as follows:
Warm up engine to operating temp, at least a 15 min drive. Shut the engine off and disconnect the TPS. Start the engine and set the idle using the default stop screw on the throttle body to approx. ~650 RPMs'. Shut off engine and reconnect the TPS. Restart the engine and observe the idle speed. If it's to high or to low, adjust the IACV ldle screw until you get the desired idle speed. That adjustment screw is in the same line as the IACV valve. It allows more or less air to enter the intake after the throttle plate, thus changing the idle speed.
Warm up engine to operating temp, at least a 15 min drive. Shut the engine off and disconnect the TPS. Start the engine and set the idle using the default stop screw on the throttle body to approx. ~650 RPMs'. Shut off engine and reconnect the TPS. Restart the engine and observe the idle speed. If it's to high or to low, adjust the IACV ldle screw until you get the desired idle speed. That adjustment screw is in the same line as the IACV valve. It allows more or less air to enter the intake after the throttle plate, thus changing the idle speed.
12-05-2004, 05:26 PM
#4
Supporting Maxima.org Member
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isn't there also a auto idle adjustment feature that our cars have that you can initiate?
search for "idle air volume learning"
so you don't have to manually adjust the screws...
search for "idle air volume learning"
so you don't have to manually adjust the screws...
12-05-2004, 07:49 PM
#5
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Update: I actually did adjust my idle by disconnecting the TPS and backing the stop screw out. Like I said though, the suspicious thing is that I had to back it all the way out. The new problem is that I've noticed, after adjusting the idle this way, is that the throttle seems really sensitive. I have to be real gentle on the throttle or I'll get a little jerkiness (I have a stick-shift). Seems like these idle adjustments have an interrelationship with throttle response.
If anyone has any other advice, please speak up. I would appreciate it.
Greg
If anyone has any other advice, please speak up. I would appreciate it.
Greg
12-06-2004, 06:30 AM
#6
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Join Date: Sep 2004
Posts: 70
Bump.
Seems to be a whole lot of questions about troublesome idles here today. Is there an idle guru out there somewhere that can help.
My current questions are:
1) specifically, how do you clean the IACV? You can't disassemble it (as far as I can tell), so how can you effectively clean it?
2) Which procedure do you use to properly set the idle: i) disconnect the TSP and adjust the stop on the throttle body, or ii) adjust the idle with the adjusting screw on the IACV?
3) Is there a method in the shop manual for diagnosing the EGR valve? I read that this can cause problems with the idle.
4) Lastly, my throttle and cruise cables seem to have a lot of slop in them. Are you supposed to adjust them by taking all the play out of them? If not, how should they be adjusted.
Thanks,
Greg
Seems to be a whole lot of questions about troublesome idles here today. Is there an idle guru out there somewhere that can help.
My current questions are:
1) specifically, how do you clean the IACV? You can't disassemble it (as far as I can tell), so how can you effectively clean it?
2) Which procedure do you use to properly set the idle: i) disconnect the TSP and adjust the stop on the throttle body, or ii) adjust the idle with the adjusting screw on the IACV?
3) Is there a method in the shop manual for diagnosing the EGR valve? I read that this can cause problems with the idle.
4) Lastly, my throttle and cruise cables seem to have a lot of slop in them. Are you supposed to adjust them by taking all the play out of them? If not, how should they be adjusted.
Thanks,
Greg
12-07-2004, 03:45 PM
#7
Senior Member
Join Date: Feb 2004
Posts: 654
Originally Posted by Julchen
Update: I actually did adjust my idle by disconnecting the TPS and backing the stop screw out. Like I said though, the suspicious thing is that I had to back it all the way out. The new problem is that I've noticed, after adjusting the idle this way, is that the throttle seems really sensitive. I have to be real gentle on the throttle or I'll get a little jerkiness (I have a stick-shift). Seems like these idle adjustments have an interrelationship with throttle response.
If anyone has any other advice, please speak up. I would appreciate it.
Greg
If anyone has any other advice, please speak up. I would appreciate it.
Greg
12-07-2004, 05:59 PM
#8
Senior Member
Join Date: Oct 2000
Posts: 5,809
Originally Posted by njmaxseltd
Default idle speed is set as follows:
Warm up engine to operating temp, at least a 15 min drive. Shut the engine off and disconnect the TPS. Start the engine and set the idle using the default stop screw on the throttle body to approx. ~650 RPMs'. Shut off engine and reconnect the TPS. Restart the engine and observe the idle speed. If it's to high or to low, adjust the IACV ldle screw until you get the desired idle speed. That adjustment screw is in the same line as the IACV valve. It allows more or less air to enter the intake after the throttle plate, thus changing the idle speed.
Warm up engine to operating temp, at least a 15 min drive. Shut the engine off and disconnect the TPS. Start the engine and set the idle using the default stop screw on the throttle body to approx. ~650 RPMs'. Shut off engine and reconnect the TPS. Restart the engine and observe the idle speed. If it's to high or to low, adjust the IACV ldle screw until you get the desired idle speed. That adjustment screw is in the same line as the IACV valve. It allows more or less air to enter the intake after the throttle plate, thus changing the idle speed.
sounds like ive been doing my adjustments the wrong way all along!
Ant
12-07-2004, 07:18 PM
#10
guys i dont think you are posed to be messin with the stop screw on the throttle body... ur posed to disconnect the tps sensor... turn the car on... then adjust the screw on the IAVC ONLY!!!... the srew that is on the throttle body is factory set and shouldnt be moved!!!
12-07-2004, 08:35 PM
#11
Senior Member
Join Date: Feb 2004
Posts: 654
Originally Posted by f550maranello2
guys i dont think you are posed to be messin with the stop screw on the throttle body... ur posed to disconnect the tps sensor... turn the car on... then adjust the screw on the IAVC ONLY!!!... the srew that is on the throttle body is factory set and shouldnt be moved!!!
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