Idle Air Control Valve - Issue continues after cleaning
03-19-17, 12:12 PM
#1
Rookie
Thread Starter
Idle Air Control Valve - Issue continues after cleaning
[99 ES300]
So this last year, I lived with a bad IACV. In the winter I would have to press on the gas and hold for a bit so that I could drive away from cold starts.
The weather just started warming up, which got rid of the need to hold the pedal for starts.. but car still doesn't "warm up rpms" at cold starts.
So after much reading/watching of IACV tutorials, I've learned a lot, and felt confident to open up my car as a beginner (exciting)
(By the way - for anyone attempting IACV cleaning, getting those 2 screws off the IACV cover was impossible with screwdriver or vise grips alone, until I decided to use a hammer on the short screwdriver.. that made it quite easy)
So.. my throttle body and IACV seemed squeaky clean already, probably because the car was dealership serviced w/ throttle body services up until I bought it at 140k miles.
Still, when I went to rotate the iacv ****, it felt slightly stuck in the closed position (left) but after a tiny twist it then moved effortlessly in both directions. I used some throttle cleaner with the drain plug disconnected and a big gallon zip lock to collect the liquid, but I also held my finger there in the drain plug and twisted the **** back n forth to clean for about 5 minutes. The liquid coming out into the zip lock bag was completely untainted with any residues. (on a side note.. even with my finger on the plug, there was throttle cleaner slowly dripping from under where the **** is.. thoughts on that later) I put the car back together and waited a couple hours just in case.
On this first startup afterwards.. my car finally "warmed up the rpms" for the first time in over a year. I was excited. I drove around the neighborhood and was excited by my great idle rpm at stop signs without the car even having completely warmed up yet. But...
when I went back home and parked on the street.. as soon as I shifted into Park.. my idle dropped to like 200rpm. After sitting there a moment flabbergasted, I turned the car off and then back on. 200 rpm. I then went into the house to sleep so I could see if a cold start after I woke up would involve "warming up the rpms" again.
It didn't. I actually had to hold my pedal even though the weather is warm now because it dropped straight to 0rpm.. which is actually worse than before.
I drove around and on the freeway, getting about 500rpm at stops even after the car was well warmed up (a few stops had normal 750-800ish). Yes, even worse than before
Still hoping things just fall into place within, and fixes itself back to the less awful state. (This is still the day after)
So, my thoughts are:
Maybe there actually is something stuck in there, but it moved out of the way with my twists and was somehow resistant to the Throttle cleaner, or avoided it somehow...
....or....
there is a possible air leak within the IACV itself (throttle cleaner was dripping out below the unit, albeit slowly) that is causing the downward airflow to force the IACV towards the closed position.. is this something that is possible?
Anyone have any other thoughts or suggestions?
I might try running some Throttle cleaner again through it in a few days.. but the fact that it's coming out 100% clear doesn't give me much hope of that working.
So this last year, I lived with a bad IACV. In the winter I would have to press on the gas and hold for a bit so that I could drive away from cold starts.
The weather just started warming up, which got rid of the need to hold the pedal for starts.. but car still doesn't "warm up rpms" at cold starts.
So after much reading/watching of IACV tutorials, I've learned a lot, and felt confident to open up my car as a beginner (exciting)
(By the way - for anyone attempting IACV cleaning, getting those 2 screws off the IACV cover was impossible with screwdriver or vise grips alone, until I decided to use a hammer on the short screwdriver.. that made it quite easy)
So.. my throttle body and IACV seemed squeaky clean already, probably because the car was dealership serviced w/ throttle body services up until I bought it at 140k miles.
Still, when I went to rotate the iacv ****, it felt slightly stuck in the closed position (left) but after a tiny twist it then moved effortlessly in both directions. I used some throttle cleaner with the drain plug disconnected and a big gallon zip lock to collect the liquid, but I also held my finger there in the drain plug and twisted the **** back n forth to clean for about 5 minutes. The liquid coming out into the zip lock bag was completely untainted with any residues. (on a side note.. even with my finger on the plug, there was throttle cleaner slowly dripping from under where the **** is.. thoughts on that later) I put the car back together and waited a couple hours just in case.
On this first startup afterwards.. my car finally "warmed up the rpms" for the first time in over a year. I was excited. I drove around the neighborhood and was excited by my great idle rpm at stop signs without the car even having completely warmed up yet. But...
when I went back home and parked on the street.. as soon as I shifted into Park.. my idle dropped to like 200rpm. After sitting there a moment flabbergasted, I turned the car off and then back on. 200 rpm. I then went into the house to sleep so I could see if a cold start after I woke up would involve "warming up the rpms" again.
It didn't. I actually had to hold my pedal even though the weather is warm now because it dropped straight to 0rpm.. which is actually worse than before.
I drove around and on the freeway, getting about 500rpm at stops even after the car was well warmed up (a few stops had normal 750-800ish). Yes, even worse than before
Still hoping things just fall into place within, and fixes itself back to the less awful state. (This is still the day after)So, my thoughts are:
Maybe there actually is something stuck in there, but it moved out of the way with my twists and was somehow resistant to the Throttle cleaner, or avoided it somehow...
....or....
there is a possible air leak within the IACV itself (throttle cleaner was dripping out below the unit, albeit slowly) that is causing the downward airflow to force the IACV towards the closed position.. is this something that is possible?
Anyone have any other thoughts or suggestions?
I might try running some Throttle cleaner again through it in a few days.. but the fact that it's coming out 100% clear doesn't give me much hope of that working.
Last edited by nikovdh; 03-19-17 at 12:17 PM.
03-19-17, 09:38 PM
#2
[99 ES300]
So this last year, I lived with a bad IACV. In the winter I would have to press on the gas and hold for a bit so that I could drive away from cold starts.
The weather just started warming up, which got rid of the need to hold the pedal for starts.. but car still doesn't "warm up rpms" at cold starts.
So after much reading/watching of IACV tutorials, I've learned a lot, and felt confident to open up my car as a beginner (exciting)
(By the way - for anyone attempting IACV cleaning, getting those 2 screws off the IACV cover was impossible with screwdriver or vise grips alone, until I decided to use a hammer on the short screwdriver.. that made it quite easy)
So.. my throttle body and IACV seemed squeaky clean already, probably because the car was dealership serviced w/ throttle body services up until I bought it at 140k miles.
Still, when I went to rotate the iacv ****, it felt slightly stuck in the closed position (left) but after a tiny twist it then moved effortlessly in both directions. I used some throttle cleaner with the drain plug disconnected and a big gallon zip lock to collect the liquid, but I also held my finger there in the drain plug and twisted the **** back n forth to clean for about 5 minutes. The liquid coming out into the zip lock bag was completely untainted with any residues. (on a side note.. even with my finger on the plug, there was throttle cleaner slowly dripping from under where the **** is.. thoughts on that later) I put the car back together and waited a couple hours just in case.
On this first startup afterwards.. my car finally "warmed up the rpms" for the first time in over a year. I was excited. I drove around the neighborhood and was excited by my great idle rpm at stop signs without the car even having completely warmed up yet. But...
when I went back home and parked on the street.. as soon as I shifted into Park.. my idle dropped to like 200rpm. After sitting there a moment flabbergasted, I turned the car off and then back on. 200 rpm. I then went into the house to sleep so I could see if a cold start after I woke up would involve "warming up the rpms" again.
It didn't. I actually had to hold my pedal even though the weather is warm now because it dropped straight to 0rpm.. which is actually worse than before.
I drove around and on the freeway, getting about 500rpm at stops even after the car was well warmed up (a few stops had normal 750-800ish). Yes, even worse than before Still hoping things just fall into place within, and fixes itself back to the less awful state. (This is still the day after)
So, my thoughts are:
Maybe there actually is something stuck in there, but it moved out of the way with my twists and was somehow resistant to the Throttle cleaner, or avoided it somehow...
....or....
there is a possible air leak within the IACV itself (throttle cleaner was dripping out below the unit, albeit slowly) that is causing the downward airflow to force the IACV towards the closed position.. is this something that is possible?
Anyone have any other thoughts or suggestions?
I might try running some Throttle cleaner again through it in a few days.. but the fact that it's coming out 100% clear doesn't give me much hope of that working.
So this last year, I lived with a bad IACV. In the winter I would have to press on the gas and hold for a bit so that I could drive away from cold starts.
The weather just started warming up, which got rid of the need to hold the pedal for starts.. but car still doesn't "warm up rpms" at cold starts.
So after much reading/watching of IACV tutorials, I've learned a lot, and felt confident to open up my car as a beginner (exciting)
(By the way - for anyone attempting IACV cleaning, getting those 2 screws off the IACV cover was impossible with screwdriver or vise grips alone, until I decided to use a hammer on the short screwdriver.. that made it quite easy)
So.. my throttle body and IACV seemed squeaky clean already, probably because the car was dealership serviced w/ throttle body services up until I bought it at 140k miles.
Still, when I went to rotate the iacv ****, it felt slightly stuck in the closed position (left) but after a tiny twist it then moved effortlessly in both directions. I used some throttle cleaner with the drain plug disconnected and a big gallon zip lock to collect the liquid, but I also held my finger there in the drain plug and twisted the **** back n forth to clean for about 5 minutes. The liquid coming out into the zip lock bag was completely untainted with any residues. (on a side note.. even with my finger on the plug, there was throttle cleaner slowly dripping from under where the **** is.. thoughts on that later) I put the car back together and waited a couple hours just in case.
On this first startup afterwards.. my car finally "warmed up the rpms" for the first time in over a year. I was excited. I drove around the neighborhood and was excited by my great idle rpm at stop signs without the car even having completely warmed up yet. But...
when I went back home and parked on the street.. as soon as I shifted into Park.. my idle dropped to like 200rpm. After sitting there a moment flabbergasted, I turned the car off and then back on. 200 rpm. I then went into the house to sleep so I could see if a cold start after I woke up would involve "warming up the rpms" again.
It didn't. I actually had to hold my pedal even though the weather is warm now because it dropped straight to 0rpm.. which is actually worse than before.
I drove around and on the freeway, getting about 500rpm at stops even after the car was well warmed up (a few stops had normal 750-800ish). Yes, even worse than before
Still hoping things just fall into place within, and fixes itself back to the less awful state. (This is still the day after)So, my thoughts are:
Maybe there actually is something stuck in there, but it moved out of the way with my twists and was somehow resistant to the Throttle cleaner, or avoided it somehow...
....or....
there is a possible air leak within the IACV itself (throttle cleaner was dripping out below the unit, albeit slowly) that is causing the downward airflow to force the IACV towards the closed position.. is this something that is possible?
Anyone have any other thoughts or suggestions?
I might try running some Throttle cleaner again through it in a few days.. but the fact that it's coming out 100% clear doesn't give me much hope of that working.
This is a long shot, but did you disconnect the battery? On every ES300 I've worked on, the ECU needs to relearn the idle after battery disco, so it idles at like 200 RPM for a while (not just ES, actually, seen it on a lot of other Lexuses and read it in FSMs). You can speed that up by holding it at 3k RPM for a minute or so.
To test if it's the IAC, once the car's warmed up pull off the throttle body intake hose and cover the IAC bypass hole with your finger. If the idle smooths out to the right RPM, IAC problem.
03-19-17, 10:48 PM
#3
Rookie
Thread Starter
By "two screws" do you mean the cover plate over the backup bimetallic spring? If so, I never saw that get dirty so don't open it.
This is a long shot, but did you disconnect the battery? On every ES300 I've worked on, the ECU needs to relearn the idle after battery disco, so it idles at like 200 RPM for a while (not just ES, actually, seen it on a lot of other Lexuses and read it in FSMs). You can speed that up by holding it at 3k RPM for a minute or so.
To test if it's the IAC, once the car's warmed up pull off the throttle body intake hose and cover the IAC bypass hole with your finger. If the idle smooths out to the right RPM, IAC problem.
This is a long shot, but did you disconnect the battery? On every ES300 I've worked on, the ECU needs to relearn the idle after battery disco, so it idles at like 200 RPM for a while (not just ES, actually, seen it on a lot of other Lexuses and read it in FSMs). You can speed that up by holding it at 3k RPM for a minute or so.
To test if it's the IAC, once the car's warmed up pull off the throttle body intake hose and cover the IAC bypass hole with your finger. If the idle smooths out to the right RPM, IAC problem.
So, to test if it's the IAC.. which hose am I taking off? There's 2 hoses, 1 goes to the left throttle body intake, 1 goes to the right throttle body intake (the right throttle body intake is the one with the IACV entrance hole). Is it safe to have a car running with a hose pulled off like that?
We're talking about these large hoses right? ( )
On a side note.. taking off those 2 screws to the cover plate was necessary to see if the **** was sticking (can't move the magnetic **** left and right without taking that cover plate off) , and getting the cleaner swished into the valve gate mechanism.. so that's why that was done. Maybe not necessary.. but it seems like a good strategy for the cleaning.
(
Last edited by nikovdh; 03-19-17 at 10:55 PM.
03-20-17, 05:45 PM
#4
Actually, I didn't disconnect the battery. Would that be necessary?
So, to test if it's the IAC.. which hose am I taking off? There's 2 hoses, 1 goes to the left throttle body intake, 1 goes to the right throttle body intake (the right throttle body intake is the one with the IACV entrance hole). Is it safe to have a car running with a hose pulled off like that?
We're talking about these large hoses right? (https://www.amazon.com/dp/B00OW31UDM/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&colid=1ZZJB0TUCV69F&coliid=I3MB8KCHR2U6YN)
On a side note.. taking off those 2 screws to the cover plate was necessary to see if the **** was sticking (can't move the magnetic **** left and right without taking that cover plate off) , and getting the cleaner swished into the valve gate mechanism.. so that's why that was done. Maybe not necessary.. but it seems like a good strategy for the cleaning.
(https://youtu.be/WsP2-HKz7vE)
So, to test if it's the IAC.. which hose am I taking off? There's 2 hoses, 1 goes to the left throttle body intake, 1 goes to the right throttle body intake (the right throttle body intake is the one with the IACV entrance hole). Is it safe to have a car running with a hose pulled off like that?
We're talking about these large hoses right? (https://www.amazon.com/dp/B00OW31UDM/ref=wl_it_dp_o_pC_S_ttl?_encoding=UTF8&colid=1ZZJB0TUCV69F&coliid=I3MB8KCHR2U6YN)
On a side note.. taking off those 2 screws to the cover plate was necessary to see if the **** was sticking (can't move the magnetic **** left and right without taking that cover plate off) , and getting the cleaner swished into the valve gate mechanism.. so that's why that was done. Maybe not necessary.. but it seems like a good strategy for the cleaning.
(https://youtu.be/WsP2-HKz7vE)
Yeah, pull off the right hose and cover the IACV port and see if the idle smooths out. It's fine to run it like that for a bit, not like anything much will get sucked in. Just put the hose back after your test.
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