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Discussion Starter · #1 ·
diagnostics say i have a faulty ICV but dont mention the EGR valve

when im driving along at 40mph in 5th or 30mph in 5th sometimes the car start violently jerking until i dip my clutch or put throttle to the floor

this doesent make sense for an IDLE valve?
 

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Discussion Starter · #4 ·
that is the one of the same problems im having on my vauxhall tigra 1.4 16v ecotec. could it not be the throttle body?
well ive done a half clean of my throttle body which seems to have made it worse, but the top of it now is clean and the bottom i can see is filthy still

am i supposed to oil the throttle body up after ive sprayed it with carb cleaner or not?


do you have your revs going up and down when idling or just the jerking?
 

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im having problems like car cutting off on traffic lights and to start it back, you have to have your foot on the gas pedal, sometimes also problems like the revvs shoot up to about 3000 when im stopped at traffic lights with foot on the clutch. however i do not have any engine menagement lights coming on?
 

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Discussion Starter · #7 ·
im having problems like car cutting off on traffic lights and to start it back, you have to have your foot on the gas pedal, sometimes also problems like the revvs shoot up to about 3000 when im stopped at traffic lights with foot on the clutch. however i do not have any engine menagement lights coming on?
well i cleaned like i said, half my throttle body and it doesent rev up and down as much, it just stays at about 1200 when i come to a stop and lowers to 900 after a while, im getting a new idle valve delivered tommorow, if its still dodgy im going to get a brush and fully clean the throttle body


btw i dont know if you know, but when using carb cleaner can i spray it directly into the throttle body while someone is revving it for me, does this help clear more gunk? and is carb cleaner not bad on the cat? as bluey smoke comes out the exhuast when i spray it in
 

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You would be far better off taking it off completely, but be careful of the paper gasket where it joins the engine. Get yourself an old toothbrush, some cocktail sticks, and a soft cloth. Once removed give it a thorough scrubbing, taking care to clean the little holes above and below the butterfly. The ICV is connected to this as well. This can be removed and sometimes dismantled and cleaned. When I did mine I filled it with thinners and shook it, emptied it and re-filled shook it. Repeated untill it all came out clear. When doing the throttle body I would also make sure the butterfly is spotless. Take extra care around the edge, and in the bore of the throttle body where it sits when closed. Any gunk in there will make it stick and also stop it from closing properly allowing more air in leading to high revving when at idle. If you look carefully at the inside of the throttle body you will see a couple of little holes. These are the inlet and outlet of the ICV. They are about 2-3mm diameter. If they are full of gunk then no air will be allowed into the engine causing your car to stall at idle. Use the cocktail sticks to clean these out. The result you are looking for it a brand new looking piece of kit when you go to put it back on. I spent ages cleaning it inside and out while watching a film.

Cheers
Neal
 

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Discussion Starter · #9 ·
You would be far better off taking it off completely, but be careful of the paper gasket where it joins the engine. Get yourself an old toothbrush, some cocktail sticks, and a soft cloth. Once removed give it a thorough scrubbing, taking care to clean the little holes above and below the butterfly. The ICV is connected to this as well. This can be removed and sometimes dismantled and cleaned. When I did mine I filled it with thinners and shook it, emptied it and re-filled shook it. Repeated untill it all came out clear. When doing the throttle body I would also make sure the butterfly is spotless. Take extra care around the edge, and in the bore of the throttle body where it sits when closed. Any gunk in there will make it stick and also stop it from closing properly allowing more air in leading to high revving when at idle. If you look carefully at the inside of the throttle body you will see a couple of little holes. These are the inlet and outlet of the ICV. They are about 2-3mm diameter. If they are full of gunk then no air will be allowed into the engine causing your car to stall at idle. Use the cocktail sticks to clean these out. The result you are looking for it a brand new looking piece of kit when you go to put it back on. I spent ages cleaning it inside and out while watching a film.

Cheers
Neal

do i have to disconnect leads from the throttle body or can i just unscrew them 4 screws and just kind of put a sheet underneath it and turn it upside down etc? and could cleaning my throttle body properly sort out this problem

when i leave go of the throttle, if im not travelling fast the car will sometimes jerk violently until i dip the clutch or open the throttle a fair bit?
 

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Al this is with the engine switched off.
Ok to take it off you first have to disconnect the throttle cable. This will be connected with a ball and socket which just pops off (socket being on the end of the cable). The cable has a black plastic grommet that clips into a bracket holding it taught. There are two electrical leads going to the assembly. One goes to the ICV, and the other goes to the throttle position sensor. Unclip these. At the back of the throttle there are two rubber pipes. Disconnect these (Don't worry about any water that may come from them. Next take off the large (2-3" diameter) pipe that goes from your airflow meter to the throttle. You should now have everything disconnected from the throttle body. There are 4 screws that hold it in place. Undo these and carefully lift the throttle body off being careful not to damage the paper gasket underneath. If you do accidently rip it get a new one from any Vauxhall dealership for a couple of quid and use it. Dont use a damaged one as you will be back to square one with airleaks etc. Now you have the throttle and body in your hands and connected to it will be the ICV. The ICV should be bolted onto the throttle body and can be removed. Again take acre with the paper gasket between if there is one. Get your scrubbing skills up to speed as you follow the directions above. On some of the ICV's (well deffo the Cavvy one as I did this to that) the ICV will be bolted together as two sections. If you undo the two screws holding it together you will get one section with a plunger on it. This plunger is the bit that gets gunked up. You should be able to push it down and it will spring back up. All the gunk can fill the bottom of this and stop the spring from working. Use the fill and shake method I described earlier to clean this out until the plunger moves freely. Assembly is just the reversal of disassembly. The reason I used thinners is because it evaporates really quickly and when you put it all back together again it is nice and dry and clean.

This is definatly a good thing to do. Its free and easy and can solve the problems you are now having. Any amount of gunk in there will affect the running of your car. Even if this does not solve all your problems then its one of the major things to discount.

Hope this helps

Neal
 

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p0505

and crankshaft sensor has come up within the past 2 weeks but its been jerking for ages and the sensor only just come up as a fault so i dont think its that
Just checked on Autodata 2 for OBD fault code 0505.

Came up with:-
Fault location.
Idle Speed Control (ISC) System.

Prob cause:-
Wiring, ISC Actuator/ ISC valve, throttle motor, throttle valve tight sticking. ECM.
 

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Just checked on Autodata 2 for OBD fault code 0505.

Came up with:-
Fault location.
Idle Speed Control (ISC) System.

Prob cause:-
Wiring, ISC Actuator/ ISC valve, throttle motor, throttle valve tight sticking. ECM.
ISC Valve = Idle Control Valve (ICV)
Throttle Valve = Big butterfly that opens and shuts when pushing the acelerator.

As I said its probaly all gunked up and not opening and shutting allowing air through when the throttle is shut. This will starve the engine of air and stall it ... or as you go to pull away and the throttle position sensor tells the ECU to close the ICV but because its stuck it throws a wobbly and flags up a warning The ECU is doing what its supposed to do. Take it off and clean it, or replace it. Either way you still need to get that throttle body cleaned to perfection as the system all works together to ensure it runs smoothly. By the way .. even if you replace the ICV with a new one you need to clear the holes above and below the throttle butterfly or you will still have issues. Even if the ICV moves freely as its supposed to do no air will get through it due to the blockage and the car will stall as soon as you take your foot off the gas.
 

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Discussion Starter · #13 ·
ISC Valve = Idle Control Valve (ICV)
Throttle Valve = Big butterfly that opens and shuts when pushing the acelerator.

As I said its probaly all gunked up and not opening and shutting allowing air through when the throttle is shut. This will starve the engine of air and stall it ... or as you go to pull away and the throttle position sensor tells the ECU to close the ICV but because its stuck it throws a wobbly and flags up a warning The ECU is doing what its supposed to do. Take it off and clean it, or replace it. Either way you still need to get that throttle body cleaned to perfection as the system all works together to ensure it runs smoothly. By the way .. even if you replace the ICV with a new one you need to clear the holes above and below the throttle butterfly or you will still have issues. Even if the ICV moves freely as its supposed to do no air will get through it due to the blockage and the car will stall as soon as you take your foot off the gas.

right im a bit confused about this, people keep saying that the idle valve has an opening to the throttle body, but my valve is all plastic apart from one bit thats a spring and thats it? it doesent appear to comminicate with anything apart from the throttle cable :S
 

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Does it look like this :



or like this :



The first is an all in one plastic ICV jobby. Sorry for some misleading but its a sealed unit as far as I know. It just unscrews from the throttle body. Take it off and clean out any debris you can find. The other unit is the Throttle position sensor. This again is sealed but doesn't need to come off. You will have to look for any airways that go in and out of the throttle and clean them where the plug on the back of the ICV sits. Please be careful and don't get any thinners/solvents on any plastic or it will melt. The ICV will pull and push the metal plug on the back to open and close the airway. Take your one off and wipe it clean with a rag it may still work, you can always swap it over later by just unscrewing the two bolts that hold it on.

Cheers
Neal
 

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Discussion Starter · #15 ·
Does it look like this :



or like this :



The first is an all in one plastic ICV jobby. Sorry for some misleading but its a sealed unit as far as I know. It just unscrews from the throttle body. Take it off and clean out any debris you can find. The other unit is the Throttle position sensor. This again is sealed but doesn't need to come off. You will have to look for any airways that go in and out of the throttle and clean them where the plug on the back of the ICV sits. Please be careful and don't get any thinners/solvents on any plastic or it will melt. The ICV will pull and push the metal plug on the back to open and close the airway. Take your one off and wipe it clean with a rag it may still work, you can always swap it over later by just unscrewing the two bolts that hold it on.

Cheers
Neal

the top one mate, can i spray carb cleaner in my air pipe from the air filter to the throttle body as it has a MAF sensor in there, and can i remove the throttle body from my car without partially draining coolant? my haynes says to partially drain but i dont want to if its not completely necessary

and also is the carb cleaner ok on my manifold and cat etc when i spray it into the throttle body?
 

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I would personally take it off buddy. You will be able to give it a good scrub down till its shiny smooth, which will give less chance of dirt build-up in the future. You can just spray carb cleaner down there but it won't clean it up any way as good as scrubbing, and you will find that the problem will either not go away, or return very quickly. As I said the breather holes for the ICV are very small (2-3mm) and you could really do with making sure they are spotless. When it says partially drain the coolant its a bit misleading. You won't lose more than half a pint or so. Wait until the engine is cold so the coolant is no longer under presuure. Undo the expansion cap and release any residual pressure. Put it back on again. take off each hose to the throttle body and plug it with a rag, bolt, or clamp it. When I did mine I had a little dribble for a few secs and then nothing. Remove the throttle body as described earlier, then clean. Any air that gets in there will bleed itself out of the system easily, just run until warm topping up your coolant if necessary.

Any carb cleaner that gets in your engine will burn off rapidly, you will get an increase in revs as it does. Don't worry about this, and it goes in seconds with no damage done. I would be reluctant to spray anything on the MAF, but other people do with no worries.

Cheers
Neal
 

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Discussion Starter · #17 ·
I would personally take it off buddy. You will be able to give it a good scrub down till its shiny smooth, which will give less chance of dirt build-up in the future. You can just spray carb cleaner down there but it won't clean it up any way as good as scrubbing, and you will find that the problem will either not go away, or return very quickly. As I said the breather holes for the ICV are very small (2-3mm) and you could really do with making sure they are spotless. When it says partially drain the coolant its a bit misleading. You won't lose more than half a pint or so. Wait until the engine is cold so the coolant is no longer under presuure. Undo the expansion cap and release any residual pressure. Put it back on again. take off each hose to the throttle body and plug it with a rag, bolt, or clamp it. When I did mine I had a little dribble for a few secs and then nothing. Remove the throttle body as described earlier, then clean. Any air that gets in there will bleed itself out of the system easily, just run until warm topping up your coolant if necessary.

Any carb cleaner that gets in your engine will burn off rapidly, you will get an increase in revs as it does. Don't worry about this, and it goes in seconds with no damage done. I would be reluctant to spray anything on the MAF, but other people do with no worries.

Cheers
Neal
ive just cleaned my throttle body again this time using a brush to clean it, i dont know if its any better really

what could it be honestly, do you have any idea? when im driving slowish between 0-50, if im in a high gear and doing lowish but not too low revs, sometimes it just starts jerking until i get past what seems to be a sticking point in the throttle, where it will continue on driving, or dipping the clutch stops it and when i dip the clutch my car is revving itself

do you think if i replace the icv it will cure this? because as i said when it starts jerking if i dip the clutch its revving itseld up and down, so the valve must be affecting it? it just doesent make sense though lol
 
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