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on a corsa B x plate 1.0L what does the idle valve do and how does it work?
I have had it off and taken it apart. all that's in it is a small motor, worm drive and a gear that leads to a plunger with a spring on it.
The plunger activates something on the throttle.

What does it do and how does it do it?

having had it apart and lubricated it I'm hoping this was the problem. starting the car the engine management light is off and it will rev all the way from tick over were as before it was tick over then over 3k

thanks dirk pitt
 

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Hi dirk, sounds like you sussed, Mine is a C with electric throttle, by what you describe the B may have a cable on....yes its as you described a worm drive valve, some are solenoids ones etc, anyway you done the right thing giving it a clean our, sometimes the worm threads wear and they do strange things, what the valve does is this, as you can probably see the valve is plumbed across the throttle butterfly, so it obvious the amount of air going through the valve bypasses the throttle plate.

In other word it revs it up..so say you have a running fault that might want the engine to stall, the ecu detects this and opens the valve and revs it up to stop it happening, under normal idle conditions when the throttle plate is shut it wouldn't idle, unless the air was going through the valve....basically it automatically controls the idle speed relative to engine load...hows that...oh by the way if it has a throttle sensor, at idle the voltage on the signal wire should be 0.9 volts, throttle shut, if its over say 1.4v it will cause idling problems....don't adjust the throttle plate stop....its pre set at factory....it will do no good, unless the flap is sticking in the hole..Fred.

on a corsa B x plate 1.0L what does the idle valve do and how does it work?
I have had it off and taken it apart. all that's in it is a small motor, worm drive and a gear that leads to a plunger with a spring on it.
The plunger activates something on the throttle.

What does it do and how does it do it?

having had it apart and lubricated it I'm hoping this was the problem. starting the car the engine management light is off and it will rev all the way from tick over were as before it was tick over then over 3k

thanks dirk pitt
 

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Discussion Starter · #3 ·
Fred, the valve looks like it does not access the throttle body. on the outside of the body it looks as if it acts as a throttle stop and works as you say, opens the throttle a very small amount with its plunger.

when it was not pugged in the engine ticked over at about 3k, plugged it back in to the electrics and it ticked over at a normal speed.

how could this valve cause the engine to die and then pick up again? it acted like fuel starvation and so I changed the fuel filter. once I had the old one off I was pretty sure the filter was not the problem

dirk pitt
 

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Hi Dirk, ok yes i know the type, the B i had was a Diesel, so i never had that, it works the same as the one i described, but instead of bypassing the flap it pushes on it and opens it...same idea in a different way, i am surprised cleaning that type done any good.

Have you cleaned out around the the throttle flap inside, that can cause that problem...but really anything that will tend to make it stall can cause that problem, even an air leak, have you done a code test and check live data, i cant remember now...but they tend to try to keep the engine idling to disguise other problems..ok best wishes from Fred.

Fred, the valve looks like it does not access the throttle body. on the outside of the body it looks as if it acts as a throttle stop and works as you say, opens the throttle a very small amount with its plunger.

when it was not pugged in the engine ticked over at about 3k, plugged it back in to the electrics and it ticked over at a normal speed.

how could this valve cause the engine to die and then pick up again? it acted like fuel starvation and so I changed the fuel filter. once I had the old one off I was pretty sure the filter was not the problem

dirk pitt
 

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I still dont understand how this ICV works, its a weird component,
I unplugged it and my car still idles, it makes no bloody sense.

It sits in a different hole which joins the body chamber or pipe assembly of the throttle body.
I have seem the Throttle body has that flap inside and when i pull the accelerator wire it opens and closes.
I have car starting issues and i am trying to figure out what it is. Mine takes ages to crank before it starts.
I need to especially after the car has been resting long say 10 hours, assist it when it takes, idle. Else it is heavy and shudders.
I have tried to replace the ICV and even clean the original.
My next suspect is the air intake sensor whatever it id technically called i dont know.
It sits on the air intake pipe.
I had to buy a new air intake pipe.
For some reason the sensor does not plug on to the harness wire connector properly
its not flush and doesnt clip on the plastic piece.
My mechanic chucked it and used my old one,
Then i thought hang on that stupid, So i have taken out the old sensor and put in the new one and the i have tried to push in the connecting plug as flush as possible.
I notice though when i went to work yesterday he Engine Management Light came on.
Anyways i dont know because of GOOD or SOLID connectivity BUT the car still doesnt start first time. I need to press down the accelerator and crank at least 5-7 seconds before it starts.
If say , i go to the shops to buy bread and milk and it stands for 30 minutes, if i crank the car , it starts immediately and that is roughly 2 seconds which is correct.
wish i knew what my next steps were.
 

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If you have to put your foot on the throttle to start it, i assume the IAC valve isn't opening as it should when you start it, the IAC valve is plummed across the throttle flap, it by passes the flap, in other words it makes the engine rev as opening the flap does, make sure the air passages are clear for the idle control valve, disconnecting it might not make any difference, it doesn't automatically shut when you disconnect it, it prob just stays where it is, you should be able e to take the valve off, turn the ignition on and watch the plunger retract....etc..Fred.
 

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Corsa ICV

I have tested the ICV also before, i unplugged it, then i started the car.
No idea, but it seemed to be fine - I dont really understand the purpose of it if it didn't do anything.

I do however remember taking it out and cleaning it and also even replacing it be cause i had irregular idling speeds. From high to low and car cutting out.

I closed the ICV not sure how i did it, then i put it in the car and started the car and the car rev'ed very high BUT it started to gradually lower the revs until the ~900 RPM mark.

reason i have played with the ICV before is to try and fix my IDLING issue that seems to work, I don't use Carburator Cleaner though it seems to leave this oily residue which is yucky.

My crank /start issue i have now has made me suspicious of the ICV also BUT something tells me it is NOT that BUT rather the Mass Air Sensor in the Air In Take Pipe, or maybe a number of things with i am hoping i can get answers to on this forum.

But yeh when i unplugged my harness from the ICV and started my car and it still idled fine, i just dont get the purpose of it.
Maybe i can try to open or close the pin and then start the car and see if the revs are constant then see what happens.

I dont really understand though what controls the ICV to operate the way it should.
 

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If you have to put your foot on the throttle to start it, i assume the IAC valve isn't opening as it should when you start it, the IAC valve is plummed across the throttle flap, it by passes the flap, in other words it makes the engine rev as opening the flap does, make sure the air passages are clear for the idle control valve, disconnecting it might not make any difference, it doesn't automatically shut when you disconnect it, it prob just stays where it is, you should be able e to take the valve off, turn the ignition on and watch the plunger retract....etc..Fred.
Not sure if you are replying to me ?

IAC Valve, hmm, where is it located, not sure what you mean by plummed.
I see the circular flap inside the throttle body , i notice when i pull the accelerator cable , i can see the flap open.

"....In other words it makes the engine rev as opening the flap does, make sure the air passages are clear for the idle control valve, disconnecting it might not make any difference, it doesn't automatically shut when you disconnect it, it prob just stays where it is,"""""" you should be able to take the valve off, turn the ignition on and watch the plunger retract....etc..Fred """"""".
I don't quite get the last part.

On Sunday i actually took off the Air In Take Pipe for the first time and anyways, i noticed it was not even clamped properly, the rubber is all deformed so i tried t straighten it out , it is better now.
I took out my ICV and cleaned it with brake and parts cleaner.
I also sprayed inside the throttle body whilst i pulled the accelerator open. you need giraffe fingers to do this, not easy.
I did see alot of black liquid coming out the ICV and also the Throttle body.
Also noticed a water pipe getting like a indent in to it from the heat of the engine piece it is sitting on , so i put some foil there in between so it can try protect it. Anyways, the only grief i have is my stupid Air sensor, or air temperature sensor, i dont know what it is called everybody seems to have a different name for it. The harness plug i have does not fit on it properly so i have tried to use rip ties and it seems to be better today but the light still came on later in my trip.
I reckon it is not seated properly and i dont want to over tighten the cable tie /rip tie. Such a bloody pain.

Anyways, interested to know if this IAC valve is one of the keys to my issue of cranking. I was told Crank sensor (not sure where the hell that is) - dripping Injectors - Starter - agg it just goes on.

Im sure i have a small issue here
 

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It lloks like some messages have gone a bit wrong here, not sure what has happened...when i say the valve is plumbed across the throttle flap i mean the air path is across the throttle flap, there is a by pass passage and the valve either lets the air though there or stops it, to rev or not rev...from Fred in Essex.
 

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It looks like some messages have gone a bit wrong here, not sure what has happened...when i say the valve is plumbed across the throttle flap i mean the air path is across the throttle flap, there is a by pass passage and the valve either lets the air though there or stops it, to rev or not rev...from Fred in Essex.
Hi Fred, man i dont understand still, sorry.
I want to , but i need to be real and be honest here, if i dont know i dont know, i wont act as if i know, like some guys and their resumes or ciriculum vitae.

I know the round flap in the body of the throttle body.
I know the air in take pipe (black pipe) connects to the throttle body...
and then sitting on the throttle body is another passage or hole in which the ICV sits.
I dont know what you mean by plumed, sorry.

Okay so thats what i have seen on my car , those things i have tried to explain, please can you try again and explain what you mean.

Anyways i am keen as you say , to try and unscrew the ICV and then leave it plugged and start the car and see what happens , you reckon i will see the pin open and close.. Well i am not sure how it will act.

Anyways, thanks Fred, need to go to work now.
And i have oil on the bottom of my sump it looks like, its all thick and ugly and wet. No idea what had gone wrong there.
 

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Hi there, maybe forget the word plumbed, all i mean was like a plummer would run pipes from on place to another, lets just say the amount of air going into the engine down the air trunk effect how much the engine revs up, with the throttle buttery closed nearly right up there is very little, low revs, when you open it more by putting your foot on the throttle it lets mor air through and revs a bit more and do on...if you open it right up it will rev full throttle, now all the idle control valve does is this, when that throttle butterfly valve is closed so hardly any air goes past it, there is an alternative route it takes around the plate, and in the middle of that alternative path is the idle control valve, that controls the amount of air that goes through that channel around the throttle butterfly valve, if it lets a little go through it will rev a little, if it elts a lot through it will rev a lot...when the engine is cold it lets quite a lot of air through making it idle quite fast, as the engine gets hot it virtually closes...and just keeps it enough to idle when hot...

Well if that path around the butterfly valve was to get blocked with carbon the valve would have no effect, and it would just be using the butterfly valve itself, and wouldnt idle very well, the IAC valve is operated by the ECU, which knows everything thats going on via the engine sensors...does that ake sense? the most common reason for oil leaks on a corsa is the oil pressure switch, top front of cylinder head near radiator...look arounf there...
oil always runs down from top to bottom...Fred.

Hi Fred, man i dont understand still, sorry.
I want to , but i need to be real and be honest here, if i dont know i dont know, i wont act as if i know, like some guys and their resumes or ciriculum vitae.

I know the round flap in the body of the throttle body.
I know the air in take pipe (black pipe) connects to the throttle body...
and then sitting on the throttle body is another passage or hole in which the ICV sits.
I dont know what you mean by plumed, sorry.

Okay so thats what i have seen on my car , those things i have tried to explain, please can you try again and explain what you mean.

Anyways i am keen as you say , to try and unscrew the ICV and then leave it plugged and start the car and see what happens , you reckon i will see the pin open and close.. Well i am not sure how it will act.

Anyways, thanks Fred, need to go to work now.
And i have oil on the bottom of my sump it looks like, its all thick and ugly and wet. No idea what had gone wrong there.
 

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Opel Corsa B / Start Crank issue

Hey Fred, I will have a look at the throttle body again but i think i have seen the plastic trunking to the throttlebody and between that is the ICV and its own sleeve in the throttle body, so i dont understand how that is an alternative route past the butterfly flap because it is before the butterfly flap.
I understand what you are saying though, with regards to more air and higher rev.
Yeh i have seen that where the car revs fast after first crank after many hours of rest , and then after it starts to warm up say 30 seconds then it starts to drop the idle.
I actually have not noticed that anymore, so this is weird.
Man this is ridiculous learning and understanding cars, but i want to know and somehow like it.
I feel it is important and also that means more peace of mind.
Let me take a look again at my throttlebody, im trying to picture what yuo were talking about,
I wlll try to take a picture of mine, just wish i had a good phone camera.
Cheers
Fred, speak later
 

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Ok well looking at it another way, take the valve off and there must be a hole in there that goes to the area before the throttle flap, and there must also be a hole either befor the flap or possibly to the outer atmsphere...but i though it would be measured air after the MAF sensor....i suppose any air leak after the throttle flap could result in higher revs...Fred.

Hey Fred, I will have a look at the throttle body again but i think i have seen the plastic trunking to the throttlebody and between that is the ICV and its own sleeve in the throttle body, so i dont understand how that is an alternative route past the butterfly flap because it is before the butterfly flap.
I understand what you are saying though, with regards to more air and higher rev.
Yeh i have seen that where the car revs fast after first crank after many hours of rest , and then after it starts to warm up say 30 seconds then it starts to drop the idle.
I actually have not noticed that anymore, so this is weird.
Man this is ridiculous learning and understanding cars, but i want to know and somehow like it.
I feel it is important and also that means more peace of mind.
Let me take a look again at my throttlebody, im trying to picture what yuo were talking about,
I wlll try to take a picture of mine, just wish i had a good phone camera.
Cheers
Fred, speak later
 
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