The mistake most techs make is unplugging the IAC with the engine still running. DO NOT do that! You can pop the IAC driver in the ecm. I know of hundreds of ecm's from GM that came in for repair and the driver for the IAC was blown due to this mistake. It may or may not pop the ecm the first time but it happens more often than not. This guy showed and explained the correct way (one of several) to test the IAC motor.
What? If you unplug it with engine on it will mess up your idle timing thats it, just replug and turn key on and off a fee times and it resets. Been there done it many times
Mine stalls after starting up, and when i unplug the connector, and then start it, it will stay running but at low idle and rough, I've cleaned the TB and IAC, is that telling me i need a new IAC?
@@mikerobo2112 well it was the original part when the car was manufactured 97, so i replaced it, but what the problem was the crank gear, it looked like the previous owner tried to pry the gear off and in the process, broke a tooth off the gear and the crankshaft position sensor could not read it's position.
@@danks2real314In the video the car idled correctly at 700 RPM with the IAC plugged in. It idled too high at 1500 RPM when it was not plugged in. It changed from 700 (good) to 1500 (bad). Change means good IAC. If the IAC was still plugged in and idling at 1500 RPM then the IAC or the wires to IAC is bad. 1500 (bad) plugged in and 1500 (bad) unplugged is no change, thus bad IAC.
It idles the same plugged as it is unplugged. Is it my wire connector or the actual iac valve? The iac valve i just bought from auto zone and thats when my problem started
My car what it does is that when I turn it on an disconnect the iac idle it queeps running the same is it cuz I idle is bad or it’s not working no more
If your car continues running normally after disconnecting the IAC (Idle Air Control) valve, it suggests the valve may not be functioning properly. This could be due to a faulty IAC valve, a clogged intake, or an issue with the idle control system that is preventing it from regulating idle speed.
@@kevind1154 Well after changing the idle valve, my shifts are really smooth, but i still have the idling problem. My next step is to change the Intake Temperature Sensor, and if that doesn't work then I'll give up...
@@Sparkyh A "soft fix" for this problem is to turn up the throttle to let more air in. I'm still waiting for the air temperature sensor to arrive and same time carburator cleaner for checking vacuum. I tried to clean my sensor with brake cleaner, but it seems like it got a bit worse. So i'm more confident that this is the problem
HELLO on my 98 KIA SPORTAGE when I first start I GET 4,000 RPMS..way too high..then when I DISCONNECT THE IAC VALVE AND RESTART CAR THE RPMS DROP TO A REGUALR 850 RPMS~~IS THIS IAC VALVE BAD?? THE CHECK ENGINE LITE CAME I WEHN I DISCONNECTED THE HARNESS.
Yes, it's likely that the IAC valve is faulty. High RPMs at startup suggest the valve is not regulating airflow properly. Disconnecting it and seeing the RPMs drop to normal indicates it might be stuck or malfunctioning. The check engine light coming on when you disconnect the harness further confirms an issue with the IAC valve.
I did this test and my car won’t start now, what did I do wrong? I unplugged it and it didn’t start, then plugged it back in and it cranked but wouldn’t start.
just want to know that when the car is NOT idling and it is running over 4 rpm around 120 kilometers per hour speed so what would be the reading of IAC valve on OBD2? plz note that car is having Cable less electronic throttle body. my car shows IAC readings fluctuating during drive too, is it normal ? thanks. in advance.
This video was helpful but not that much because running your engine with something unplugged can cause it to go into limp mode ... And most of all electrical devices unplugged is different compared to a electrical device that is worn down or maybe blocked off by dirt or debris...👍🏼
@@jbortega1178 sprayed down ICV internally or electrical connector? Or sprayed down throttle body? I have same issue. Idles PERFECT if I put it in gear. In park/neutral it idles rough
doesn't prove shit... when mine is hooked up on my 4.6L it races very high RPM's nearly 1300, and unplugged runs below normal idle rpm. That isn't telling me a dam thing and had been through 2 of these already in a very short time!!
@@steveandrews8301 Got rid of the old car...LKQ payed me $750 for it. Now I uber all over town. BTW my rear axle broke inside somewhere I couldn't see or find after running over curb.
If your Hyundai's RPM drops in the morning, it could be due to a cold start issue, often related to the idle air control (IAC) valve, throttle body, or a vacuum leak. Cleaning the throttle body or checking for leaks may help resolve the problem.
Ignorance at its best...if ur gonna show us a malfuntion then SHOW IT... mine was racing at 3000 rpms with it connected...not driveable...disconect and idle is normal...with stalls of course but driveable to go get parts...i wouldnt let u change my air in them tires
I understand your frustration. If your car was racing at 3000 RPMs with the IAC connected, and dropping to normal idle when disconnected, it points to a faulty IAC valve. While disconnecting the IAC may temporarily help, replacing the valve or cleaning the throttle body would likely fix the root cause of the issue.
That doesn't prove that it's working the way it should all you're doing when you unplug that sensor all you're doing is making it so that your throttle and the floor doesn't work
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The mistake most techs make is unplugging the IAC with the engine still running. DO NOT do that! You can pop the IAC driver in the ecm. I know of hundreds of ecm's from GM that came in for repair and the driver for the IAC was blown due to this mistake. It may or may not pop the ecm the first time but it happens more often than not. This guy showed and explained the correct way (one of several) to test the IAC motor.
They need to make the ECM (and other computers) fault tolerant then.
Wtf is a iac driver?
They can be unplugged with no problem on hondas
How would you know it’s popped?
What? If you unplug it with engine on it will mess up your idle timing thats it, just replug and turn key on and off a fee times and it resets. Been there done it many times
Simplicity at its best. Thanks bro
Theres no idle ? Ge....s
This is a great test , thank for sharing
What if the IAC is stuck closed? Then the test wouldn't work presumably.
Seafoam the hell out of it
When you start the car, should there be no voltag to the IAC and 12 V when you accelerate on and off basically or should it be different?
Best video to test Iac sensor i seen 👍 Thanks 👍
Mine stalls after starting up, and when i unplug the connector, and then start it, it will stay running but at low idle and rough, I've cleaned the TB and IAC, is that telling me i need a new IAC?
Could be vacuum dude. Soapy water test.
@@mikerobo2112 well it was the original part when the car was manufactured 97, so i replaced it, but what the problem was the crank gear, it looked like the previous owner tried to pry the gear off and in the process, broke a tooth off the gear and the crankshaft position sensor could not read it's position.
Pardon a rookie question, but what is TB?
@@Wavemaninawe the throttle body in a sense it's the carburetor
@@dannymartinez8314
OK, thanks!
I have stalling SAAB and am trying to figure out what the issue is.
What if the IAC is already bad when doing this test. Will the idle still change? As it already bad.
If it's bad then there will be no change.
@@whisperedgoodbye9985so the start will be cleaner or worse to tell if its bad ?
@@danks2real314In the video the car idled correctly at 700 RPM with the IAC plugged in. It idled too high at 1500 RPM when it was not plugged in. It changed from 700 (good) to 1500 (bad). Change means good IAC. If the IAC was still plugged in and idling at 1500 RPM then the IAC or the wires to IAC is bad. 1500 (bad) plugged in and 1500 (bad) unplugged is no change, thus bad IAC.
I just installed a new IAC and its rev 1300.. why?
Check for vacuum leaks, clean the throttle body inside out.
It idles the same plugged as it is unplugged. Is it my wire connector or the actual iac valve? The iac valve i just bought from auto zone and thats when my problem started
Did u ever find out
My car what it does is that when I turn it on an disconnect the iac idle it queeps running the same is it cuz I idle is bad or it’s not working no more
If your car continues running normally after disconnecting the IAC (Idle Air Control) valve, it suggests the valve may not be functioning properly. This could be due to a faulty IAC valve, a clogged intake, or an issue with the idle control system that is preventing it from regulating idle speed.
When i rev up to 3k, SOMETIMES it drops a bit too far and you can feel the engine almost stalling
Same here! Did you figure out the issue?
@@kevind1154
I'm guessing it's the Idle Control Valve.
Mine is still on the way, thought about changing it while also doing headgasket and drive belts
@@kevind1154
Well after changing the idle valve, my shifts are really smooth, but i still have the idling problem.
My next step is to change the Intake Temperature Sensor, and if that doesn't work then I'll give up...
@@UltimatumDemon thanks for the tip g ppreciate it
@@Sparkyh A "soft fix" for this problem is to turn up the throttle to let more air in.
I'm still waiting for the air temperature sensor to arrive and same time carburator cleaner for checking vacuum.
I tried to clean my sensor with brake cleaner, but it seems like it got a bit worse. So i'm more confident that this is the problem
Super helpful, thank you
Hey you, This is one of the basic ways to check. There is another way to check faster!
HELLO on my 98 KIA SPORTAGE when I first start I GET 4,000 RPMS..way too high..then when I DISCONNECT THE IAC VALVE AND RESTART CAR THE RPMS DROP TO A REGUALR 850 RPMS~~IS THIS IAC VALVE BAD?? THE CHECK ENGINE LITE CAME I WEHN I DISCONNECTED THE HARNESS.
850 rpms is a lil to much.
Yes, it's likely that the IAC valve is faulty. High RPMs at startup suggest the valve is not regulating airflow properly. Disconnecting it and seeing the RPMs drop to normal indicates it might be stuck or malfunctioning. The check engine light coming on when you disconnect the harness further confirms an issue with the IAC valve.
How to replace iac? Mine has a problem.
i’m chasing a high idle at 1k in my 95 f150 5.0. Unplugging the iacv drops the idle to normal 650-800
I did this test and my car won’t start now, what did I do wrong? I unplugged it and it didn’t start, then plugged it back in and it cranked but wouldn’t start.
The driver for it has been corrupted
Nicely done short and simple
Simple and useful, thanks
My car won’t start when intake is off
just want to know that when the car is NOT idling and it is running over 4 rpm around 120 kilometers per hour speed so what would be the reading of IAC valve on OBD2? plz note that car is having Cable less electronic throttle body.
my car shows IAC readings fluctuating during drive too, is it normal ? thanks. in advance.
Guys help please... I dunno what to do anymore, I replaced my IACV, my TPS as well but my idle is still at 4000 rpms.
@cotteeart have you looked the symptoms up on forums with your year make and model? Have you tested for a vaccum leak?
If unplugged mean idel is faulty please momes states same ? Unplugged. Nissan micra 2002 petrol
simple, i like it. that throttle body valve is super dirty lol
Can u tell me what part of my meter I put it on to check my IAC I don't even know how to read it
Obd port
Gracias amigo, very helpful
Where would the iac valve is on a 2013 kia soul 1.6
Follow your air intake hose from air cleaner to throttle body - it's in there somewhere along that air line pathway.
And by the way the throttle position the IAC is on the opposite side
The throttle position sensor and the iac are two totally separate things.
@@hunterautomotive4842 Can a defective throttle position sensor negatively impact idle?
After starting the car the rpms take 2 minute's to go down to normal rpms while there is a weird noise In the engine
Aynı sorun bende de var 😢
That's normal
Thank you!
Thank you so much
What do you unplug???
What do you use to clean the ICA?
He showed what he unplugged. You can clean it with Mass Air Flow Sensor cleaner.
This test doesn't work with my 02 Mustang.
This video was helpful but not that much because running your engine with something unplugged can cause it to go into limp mode ... And most of all electrical devices unplugged is different compared to a electrical device that is worn down or maybe blocked off by dirt or debris...👍🏼
So what would make your idle go up and down? While in park
Throttle Position Sensor and dirty ICV sensor connector.
@@mrjaybennett80 yeah..I sprayed it down... been good ever since.. thnx
@@jbortega1178 sprayed down ICV internally or electrical connector? Or sprayed down throttle body? I have same issue. Idles PERFECT if I put it in gear. In park/neutral it idles rough
@@mrjaybennett80 can I use maf sensor cleaner on my IAC or TB sensors?
@@macknumber9 yes.. that's exactly how I fixed the problem.. been 5 months no problems
Excellent
my car sits at 1krpm but when driving if i accelerate and then clutch in it can drop to a stall,??
I had this issue on my old car, it even died on me every now and then. A new idle valve fixed in on the spot.
Lol that's great it bounces on 1500, like my problem plugged or unplugged. But it was replaced, maybe its the harness or the ecm still.
Handy. What did unplug the wire to the iacv?
I'm having the opposite problem
With that throtle valves you gone have all kind of issues that thing is thyrty I would cleaned before anything the whole engine is dusty.
Perfect
doesn't prove shit... when mine is hooked up on my 4.6L it races very high RPM's nearly 1300, and unplugged runs below normal idle rpm. That isn't telling me a dam thing and had been through 2 of these already in a very short time!!
Clean your throttle body
Well it tells you that its not the valve😂
Did you ever figure it out what the problem was? Thanks.
@@steveandrews8301 Got rid of the old car...LKQ payed me $750 for it. Now I uber all over town. BTW my rear axle broke inside somewhere I couldn't see or find after running over curb.
@@toddgilmore118 thanks for the reply / answer, Todd. Bummer on the broken rear axle, ouch.
my car is hyundai it is good but in the morning rpm down
If your Hyundai's RPM drops in the morning, it could be due to a cold start issue, often related to the idle air control (IAC) valve, throttle body, or a vacuum leak. Cleaning the throttle body or checking for leaks may help resolve the problem.
Bravo
First off that's not a IAC that is a throttle position sensor
Arlie Glen
Very nice work thanks for sharing
U shut it off to quick
in my car it revs up and down when pluged in, when unplugged it revs normally
Hahaha me too! I was like wtf???
I believe that means it's bad
Ignorance at its best...if ur gonna show us a malfuntion then SHOW IT... mine was racing at 3000 rpms with it connected...not driveable...disconect and idle is normal...with stalls of course but driveable to go get parts...i wouldnt let u change my air in them tires
I understand your frustration. If your car was racing at 3000 RPMs with the IAC connected, and dropping to normal idle when disconnected, it points to a faulty IAC valve. While disconnecting the IAC may temporarily help, replacing the valve or cleaning the throttle body would likely fix the root cause of the issue.
That doesn't prove that it's working the way it should all you're doing when you unplug that sensor all you're doing is making it so that your throttle and the floor doesn't work
great tip guys, and nice observation@gripfreak