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jdnet

Cleaning The Iac Valve And A Basic Engine Cleanup

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The Don,

Thanks mate! The steps in the first link you've shared is explained exactly in that order in the workshop manual. Unfortunately, my multi meter is busted and I'm unable to test at home. I too am pretty sure that it's the ICV. I went to work by car today and I had the ICV connector disconnected the whole time. The idle although pretty low during a cold start reached about 1500 when warm and I could drive with the AC on as it came down and settled at 800 and didn't move at all. No fluctuations. I spend quite a few minutes stuck in traffic too.

I called this contact of mine who works at UniMo and explained the situ over the phone and he asked me to come over so that he can check everything out and help me isolate the problem. I think they have a special harness that plugs into a diagnostic scanner from which they can check the ICV (and any sensor for that matter) to determine if they are faulty. When I explained to the guy what I did, his first response was that they do not clean the ICV using carb cleaner as it causes problems. :S So you're absolutely right on this on your very first reply.

If the ICV is faulty (which I'm guessing it is), then I'll first look for a recon one at Delkanda, or order from eBay.

Frustrating days... sigh! :(

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I'm not a tech person to help you here, Davy but wish you good luck to solve this. I know how it feels as I've recovered from a similar condition recently. In my case carb cleaner worked.

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I think Davy's ICV was probably on its way out. So it probably needed replacement anyway.

So the two points which are useful to come out of this exercise are

1. Plug the air bypass hole before you spray carb cleaner into a throttle body

2. Don't clean ICV with carb cleaner

3. Don't spray carb cleaner into cavities. If you do make sure you dry it properly.

4. Reset the Throttle position sensor after a throttle body clean

5. Clean the MAF using contact cleaner when you do a throttle body clean up, and the air intake pipes with water and dry. (the other culprit for rough idle).

6. Make sure there are no vaccume leaks. Apparently a good way to test it is to spray a bit of WD40 into places you suspect and if the idle speed suddenly goes up a bit then there is probably a leak!

7. Make sure the hot water lines going into the throttle body are not blocked or leaking.

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Okay here's an update:

I went to UniMo in the morning and got the car checked up. The mech scanned the car with a Mitsubishi specific dagnostic unit and observed the behaviour of the car for about 10 minutes. This was one instance on which I wished that all the issues with the fuel injection system would surface, so that I could get to know them. :P Anyway, after scanning, he confidently said that the issue is with the ICV (They call it the "stepper motor" - the same term used in the workshop manuals.). According to him, this is a common issue on the CS especially after doing about 100,000km.

So The Don is right. And yes, I think the ICV was on its way out from a long time judging by the unpredictable behaviour in rare occasions. Time to source a new one now. Hoping for the best!

I'm not a tech person to help you here, Davy but wish you good luck to solve this. I know how it feels as I've recovered from a similar condition recently. In my case carb cleaner worked.

Thanks mate! I think I'm begining to see the light at the end of the tunnel. :)

Edited by Davy

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I think Davy's ICV was probably on its way out. So it probably needed replacement anyway.

So the two points which are useful to come out of this exercise are

1. Plug the air bypass hole before you spray carb cleaner into a throttle body

2. Don't clean ICV with carb cleaner

3. Don't spray carb cleaner into cavities. If you do make sure you dry it properly.

4. Reset the Throttle position sensor after a throttle body clean

5. Clean the MAF using contact cleaner when you do a throttle body clean up, and the air intake pipes with water and dry. (the other culprit for rough idle).

6. Make sure there are no vaccume leaks. Apparently a good way to test it is to spray a bit of WD40 into places you suspect and if the idle speed suddenly goes up a bit then there is probably a leak!

7. Make sure the hot water lines going into the throttle body are not blocked or leaking.

1. For your first point, I think some throttle bodies shouldn't be sprayed with carb/throttle body cleaner at all. The best practice should be to spray the cleaning liquid onto a clean piece of cloth and clean the throttle body with it. This of course means that you will not be able to any cavities as your third point describes - which is good. The below extract is rom my workshop manual and it specifically mentions all this:

4G18ThrottleBodyCleaning_zps64e00fcb.jpg

2. For your second point, yes this is true. I will never in my life apply carb cleaner onto an ICV again. If you really want to clean the ICV, the best way is to apply carb cleaner onto a cloth and clean the ICV with it.

To add more on to your list:

8. If the throttle body is taken off from the intake manifold to be cleaned up, make note of the way the throttle body gasket is installed. I read in the manual that erratic idle maybe caused by positioning the gasket incorrectly during installation.

9. If gasket maker is used to re-seat the throttle body on the intake manifold, use as little gasket maker as possible. Using excessive amounts of gasket maker can cause some cavities to get sealed off which will result in idling problems.

10. If there is no restriction of spraying carb cleaner on the vehicle specific to you, then make sure you remove all sensors from the throttle body (TPS, ICV) before you do.

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I wonder how many throttle bodies and sensors have been destroyed by mechanics cleaning it the wrong way. Some people actually use diesel rather than throttle body/ carb cleaner as well.

The most important bit is to TAKE CARE and proceed slowly and cautiously.

Davy, maybe you and I should start a workshop specilising in these so called tune ups :) We've learned a lot from our experiences.

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Probably a lot. As a matter of fact, I did talk to a mechanic about this and he advised me to clean the ICV with a bit of petrol or carb cleaner. I guess it depends on the ICV unit itself. The ICV that jdnet has cleaned using carb cleaner at the begining of this thread is a metal unit and it looks like it can be cleaned that way - just an assumption. My ICV hates carb cleaner and I'm guessing most Mitsubishi ICVs also do.

Davy, maybe you and I should start a workshop specilising in these so called tune ups :) We've learned a lot from our experiences.

I definitely learnt a lot through the whole experience, and I know what to look out for the next time I try this. So, combined, we really can start a workshop! :)

Edited by Davy

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Davy and Don

Count me as one your customers for tune up :yahoo:

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Oh look! We have customers already! :D

By the way, I managed to find an ICV and I will be collecting it tomorrow. Will update on the outcome. Fingers crossed!

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Oh look! We have customers already! :D

By the way, I managed to find an ICV and I will be collecting it tomorrow. Will update on the outcome. Fingers crossed!

How much did you have to pay for the ICV? The first time nearly 10 years ago, I had to pay 3500. The next time I got scammed and ended up paying 7500 (I was scammed by my mechanic).

There are unfortunately a few models of ICV which look the same, but the length of the actuator is different, hence you need to match the exact part number.

Its good that we have customers already. A few more and I'll give up my day job :P A funny story on the side. After my A/L's which I didn't do that well in, my mother tells me, if I wanted to be a motor mechanic she will be completely supportive of my decision. This was a big deal since sadly in our country they are often looked down on as grease monkeys.... I thought of it, could not see how I could make a reasonable living out of it, and did a computing degree instead. I've done reasonably well out of that, but sometimes I think of my career choices :)

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How much did you have to pay for the ICV? The first time nearly 10 years ago, I had to pay 3500. The next time I got scammed and ended up paying 7500 (I was scammed by my mechanic).

There are unfortunately a few models of ICV which look the same, but the length of the actuator is different, hence you need to match the exact part number.

Its good that we have customers already. A few more and I'll give up my day job :P A funny story on the side. After my A/L's which I didn't do that well in, my mother tells me, if I wanted to be a motor mechanic she will be completely supportive of my decision. This was a big deal since sadly in our country they are often looked down on as grease monkeys.... I thought of it, could not see how I could make a reasonable living out of it, and did a computing degree instead. I've done reasonably well out of that, but sometimes I think of my career choices :)

The ICV was picked out by the contact at UniMo and he quoted 15,000 for it but I managed to get it down to 12,000. Considering the fact that a brand new costs almost 40,000 at the agents, I thought this was the right call. The ones on eBay also cost about the same amount or higher to be bought down.

About the models of ICV that looks the same, yes I almost ended up buying one but did not because the actuator was short. I remembered this place at Bellanthara where I bought my radiator from, and thought of checking it out last week. I went there by three wheeler on the first day and asked for the ICV and they emptied a whole big box of ICVs in front of me. I did a bit of peering and found out a couple that looked almost the same. I had seen the same model on the net when I was Googling for this (and with the same part number too), but I was reluctant to buy because it was shorter. They asked 6000 for it and I told them that I will bring the car on the following day and try it on and buy if it works. So I took the car there and took off the ICV myself and installed the one they had after "correctly" cleaning the ICV with a bit of carb cleaner on a cloth. :) Unfortunately, as soon as I started the engine, the RPM shot upto 3000 and swung back and forth from 2500 to 3000 in a breathing pattern. So I didnt end up buying the thing. The guys at the spare parts shop asked me "sir mokadda oken kerenne?" and I had to lecture them about what an ICV is and it's function. :P

You know what machan, I think you and I have followed the same path. I have had the same feelings about my career. It was between automotive engineering and computing, and for pretty much the same reasons as you, I selected computing and have been at it for over 6 years now - all good. But looking back, sometimes I wish I had thought differently back then. So I know exactly what you mean. :) This is probably why I find reasons to take off parts of my car during the weekend and create problems that arn't even there, with the hope getting some grease on my hands. :)

Edited by Davy
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You know what machan, I think you and I have followed the same path. I have had the same feelings about my career. It was between automotive engineering and computing, and for pretty much the same reasons as you, I selected computing and have been at it for over 6 years now - all good. But looking back, sometimes I wish I had thought differently back then. So I know exactly what you mean. :) This is probably why I find reasons to take off parts of my car during the weekend and create problems that arn't even there, with the hope getting some grease on my hands. :)

now I know very well that i'm not alone :P:D

having said that, I learnt (by doing of course) if it doesn't give any trouble, better not start with it until it gives some.

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Of course in Autolanka you are always in good company :)

I was always into cars, but the reason why I got into the mechanical stuff is because sometimes, if you want it done well, you sometimes have to do it yourself! And I like fixing stuff, anything broken.

That RPM shooting up, is normal the first time sort of until the ECU learns to manage itself. It's one of the tricky bits around this. Always keep the original for the part number. If I was at home, and if the numbers matched I could have lend you one myself. I have 2 spare throttle bodies and about 3 of them. Sometimes you pick them up for cheap on ebay from the UK since the Mitsubishi's are not as popular and the same parts were used in Protons. Its easier to find from US but prices are higher. The last one I got only cost me £15.

You might have to help me with that contact at Unimo. I need some prices quoted for my Mirage before I decide where to source parts from.

Edited by The Don

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Yeah, true. My dad was one reason I became a grease monkey. :) He was so reluctant to take his car to garages and opted to DIY most of the repairs because he wanted it done right. I used to sit back and watch in awe wen I was little. Learnt a lot from him and even now I call him to give me a hand, when he's around.

As for the RPM shooing up, I left the engine on for a good 5 minutes or so, but it was the same. Do you think I should have left it running for longer? Or taken the car for a test drive maybe? I honestly didn't feel comfortable because the engine was sort of screaming at 3000 RPM and the whole power plant was moving back and forth with a lot of stress on the mounts because of the rapidly changing idle.

Looks like you have had your times with throttle bodies huh? 2 spares is a lot! And thanks for the kind offer machan, if you had a matching ICV, I could have easily diagnosed the issue too. Let me know when you're ready to purchase parts for the Mirage. I know a couple of other guys who might be able to source parts for you.

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Yeah, true. My dad was one reason I became a grease monkey. :) He was so reluctant to take his car to garages and opted to DIY most of the repairs because he wanted it done right. I used to sit back and watch in awe wen I was little. Learnt a lot from him and even now I call him to give me a hand, when he's around.

As for the RPM shooing up, I left the engine on for a good 5 minutes or so, but it was the same. Do you think I should have left it running for longer? Or taken the car for a test drive maybe? I honestly didn't feel comfortable because the engine was sort of screaming at 3000 RPM and the whole power plant was moving back and forth with a lot of stress on the mounts because of the rapidly changing idle.

Looks like you have had your times with throttle bodies huh? 2 spares is a lot! And thanks for the kind offer machan, if you had a matching ICV, I could have easily diagnosed the issue too. Let me know when you're ready to purchase parts for the Mirage. I know a couple of other guys who might be able to source parts for you.

Well the first time mine shot up as well but then came down within about a minute. If it stays up, that means the ICV is sticking, at which point you should throw it away.

What you could have done is race the car once and let the accelorator go and see what happens. Did you play around with the idle air screw by any chance?

I'm after 2 fenders for my CA3A coupe, though I will take anything anybody has to be honest. But brand new I was hoping to get down possibly the roof, missing trim (bits from the dashboard which have UV damage and turned to dust), valve seats, piston rings and the gasket kit. The car runs fine, but I wanted to open up the engine and de carbonise it, and might has well change the rings and valve seats at the same time as well was the logic. Thats not urgent. But the body parts are, as I wanted to put it in to repair some rust asap (its got the dreaded Mitsi roof rust).

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Well the first time mine shot up as well but then came down within about a minute. If it stays up, that means the ICV is sticking, at which point you should throw it away.

What you could have done is race the car once and let the accelorator go and see what happens. Did you play around with the idle air screw by any chance?

I'm after 2 fenders for my CA3A coupe, though I will take anything anybody has to be honest. But brand new I was hoping to get down possibly the roof, missing trim (bits from the dashboard which have UV damage and turned to dust), valve seats, piston rings and the gasket kit. The car runs fine, but I wanted to open up the engine and de carbonise it, and might has well change the rings and valve seats at the same time as well was the logic. Thats not urgent. But the body parts are, as I wanted to put it in to repair some rust asap (its got the dreaded Mitsi roof rust).

I let the car run for a few minutes or so and I did pull the accelerator cable to race the engine a couple of times, but the result was the same. And no I didn't touch the idle adjustment screw as I figured that it's already preset by the manufacturer. There is this paint marking over the screw to indicate the position set by the manufacturer and it's on that exact spot. Oh well, I guess I'll only get to know today when I try out the new ICV. Hoping for the best.

A Mirage coupe? That's one rare car right? I've seen the saloon and the hatch, but I don't think I've seen a coupe over here. Since this is from the same period as the Lancer CB (which is somewhat popular), you could be looking at a lot of intergchangeable parts from the CB. Arn't the fenders also compatible? Or do you have the version where the turn indicator is a bit different from the CB (in which case the fender is different)?

Roof rust was a problem on the Lancer CB as well. I know of a guy who had a Lancer CB3 who had a lot of trouble due to roof rust. He ended up repairing it and re-doing the whole headliner as well if I remember. If yours has a stock 4G15 engine, you should be able to easily source engine parts off Panchi IMO. Also, I'm pretty sure I saw a front cut of a Mirage (of this era) somewhere in between Delkanda and Gansabha Junction in Nugegoda. Will confirm the next time I pass by.

Keep me posted on when you're ready for the parts, I will give you the contacts and even join you in the search. :)

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now I know very well that i'm not alone :P:D

having said that, I learnt (by doing of course) if it doesn't give any trouble, better not start with it until it gives some.

Hey Guys,

Same with me :speechless-smiley-004:

Father being a mechanic I had that feeling to be with grease , but end result as you 2 an IT Engineer. :sport-smiley-027:

Now my 8 yr old son is after vehicles, so if he wants to be a mech, i'll support that decision with no second thoughts. AND if he starts a workshop some day, I'll through this Laptop away and join him as assistant :sport-smiley-004: .

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I let the car run for a few minutes or so and I did pull the accelerator cable to race the engine a couple of times, but the result was the same. And no I didn't touch the idle adjustment screw as I figured that it's already preset by the manufacturer. There is this paint marking over the screw to indicate the position set by the manufacturer and it's on that exact spot. Oh well, I guess I'll only get to know today when I try out the new ICV. Hoping for the best.

A Mirage coupe? That's one rare car right? I've seen the saloon and the hatch, but I don't think I've seen a coupe over here. Since this is from the same period as the Lancer CB (which is somewhat popular), you could be looking at a lot of intergchangeable parts from the CB. Arn't the fenders also compatible? Or do you have the version where the turn indicator is a bit different from the CB (in which case the fender is different)?

Roof rust was a problem on the Lancer CB as well. I know of a guy who had a Lancer CB3 who had a lot of trouble due to roof rust. He ended up repairing it and re-doing the whole headliner as well if I remember. If yours has a stock 4G15 engine, you should be able to easily source engine parts off Panchi IMO. Also, I'm pretty sure I saw a front cut of a Mirage (of this era) somewhere in between Delkanda and Gansabha Junction in Nugegoda. Will confirm the next time I pass by.

Keep me posted on when you're ready for the parts, I will give you the contacts and even join you in the search. :)

Hi Davy, Mine is a 1993 model. The front end (Fenders, Bonnet, lights etc) are the same as the sedan, and so is probably the rear. The doors are obviously different and so is the roof etc (there could be other differences as well). Sourcing most mechanical parts have not been an issue at all, but Mirage body parts were always a bit rare compared to the Lancers. The fenders have been banged up a bit due to repeated light accidents, and probably the best way to restore to original is to replace them as its difficult to find good tinkerers. This has happened because I'm not home and my father sometimes drives the car, but I figure its better than letting it lie idle which causes more issues.

The roof either need fabrication or replacement. Its only about 40K to buy brand new but getting it to SL has proved problamatic..

The coupe is a bit rare. But I always wanted to buy a Mirage, and armed with little money I collected doing part time jobs as a student, I bought one on my return in 2004. But I've hardly got to enjoy the car as I also found a job with a company in Newcastle and I've worked in the UK since. I've seen at least two other coupes (a metallic blue one and I don't remember the colour of the other one) but not sure if any of them are ASTI Z, which is the highest grade for this model. It comes stock with the 4G91 engine which has about 30 more horsepower than the 4G15. This is rarer than the 4G15 but again loads of parts interchangeable and I've found complete engines in Panchikawatte (I needed the AC compressor once).

If you have seen a half cut please let me know where. I'll send somebody to buy that immediately! I've passed by Delkanda quite a lot during my time home last month but I didn't see any :(

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Hey Guys,

Same with me :speechless-smiley-004:

Father being a mechanic I had that feeling to be with grease , but end result as you 2 an IT Engineer. :sport-smiley-027:

Now my 8 yr old son is after vehicles, so if he wants to be a mech, i'll support that decision with no second thoughts. AND if he starts a workshop some day, I'll through this Laptop away and join him as assistant :sport-smiley-004: .

It's a typical career path in Sri Lanka sadly. I think we are practical people, but at times we need to follow our hearts as well.

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Hi Davy, Mine is a 1993 model. The front end (Fenders, Bonnet, lights etc) are the same as the sedan, and so is probably the rear. The doors are obviously different and so is the roof etc (there could be other differences as well). Sourcing most mechanical parts have not been an issue at all, but Mirage body parts were always a bit rare compared to the Lancers. The fenders have been banged up a bit due to repeated light accidents, and probably the best way to restore to original is to replace them as its difficult to find good tinkerers. This has happened because I'm not home and my father sometimes drives the car, but I figure its better than letting it lie idle which causes more issues.

The roof either need fabrication or replacement. Its only about 40K to buy brand new but getting it to SL has proved problamatic..

The coupe is a bit rare. But I always wanted to buy a Mirage, and armed with little money I collected doing part time jobs as a student, I bought one on my return in 2004. But I've hardly got to enjoy the car as I also found a job with a company in Newcastle and I've worked in the UK since. I've seen at least two other coupes (a metallic blue one and I don't remember the colour of the other one) but not sure if any of them are ASTI Z, which is the highest grade for this model. It comes stock with the 4G91 engine which has about 30 more horsepower than the 4G15. This is rarer than the 4G15 but again loads of parts interchangeable and I've found complete engines in Panchikawatte (I needed the AC compressor once).

If you have seen a half cut please let me know where. I'll send somebody to buy that immediately! I've passed by Delkanda quite a lot during my time home last month but I didn't see any :(

Well I don't think I remember seeing any Mirage coupes of that era. There's one Mirage coupe at Athurugiriya but that is the one that came alongside the Lancer CK. So I guess you've got some treasure over there at home, just waiting for you. :)

I'm positive that I saw a half cut. It was this greenish silver colour and it was on the left hand side of the road when travelling from Maharagama towards Nugegoda. I'll confirm the location if and as soon as I find it. I'm always on the lookout for Mitsu parts when I pass the area by bus especially, so I'm pretty sure that I was not dreaming.

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Well I don't think I remember seeing any Mirage coupes of that era. There's one Mirage coupe at Athurugiriya but that is the one that came alongside the Lancer CK. So I guess you've got some treasure over there at home, just waiting for you. :)

I'm positive that I saw a half cut. It was this greenish silver colour and it was on the left hand side of the road when travelling from Maharagama towards Nugegoda. I'll confirm the location if and as soon as I find it. I'm always on the lookout for Mitsu parts when I pass the area by bus especially, so I'm pretty sure that I was not dreaming.

Machang, if there is one (this has the same front as the Proton Wira, but the proton body parts don't fit cleanly due to subtle differences, so it has to be Mitsubishi) please send me a message asap!!!

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Machang, if there is one (this has the same front as the Proton Wira, but the proton body parts don't fit cleanly due to subtle differences, so it has to be Mitsubishi) please send me a message asap!!!

Check your inbox. :)

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I got my hands on the new ICV toady. Set me back 12,000 as I mentioned before, but it was a brand new unit with packing as well. Swapped it with the old one, reset the ECU and BAM!! - the idle is back to normal!!! Perfect idling with and without AC. Can't even feel the AC coming on now because the idling is kept spot on. No abrupt increases in RPM as well. Happy happy happy! :)

The Don, thanks again for the help and the very valuable information shared here. I'm sure someone will find this useful someday.

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I got my hands on the new ICV toady. Set me back 12,000 as I mentioned before, but it was a brand new unit with packing as well. Swapped it with the old one, reset the ECU and BAM!! - the idle is back to normal!!! Perfect idling with and without AC. Can't even feel the AC coming on now because the idling is kept spot on. No abrupt increases in RPM as well. Happy happy happy! :)

The Don, thanks again for the help and the very valuable information shared here. I'm sure someone will find this useful someday.

Don't mention it man! But I'm really surprised you managed to get a brand new unit for 12K Thats well worth the price!

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Don't mention it man! But I'm really surprised you managed to get a brand new unit for 12K Thats well worth the price!

Yeah, considering the fact that it's nearly 40,000 at the agent, this is quite a good price I guess.

And here's the new ICV:

CAM00864_zps7842d50a.jpg

This is how the car idles now. As smooth as ever. :)

https://vimeo.com/91508767

Also, I couldn't help but try dismantling the old ICV as per the instructions in the YouTube video I had shared earlier. And most of the people who tried this had broken the plastic locking mechanism of the actuator because the plastic was brittle. Mine was no exception. It just snapped into a million pieces as soon as I held the pliers to unlock it. (Covered the actuator with a piece of thick cloth to try avoid damaging it, but no luck)

I took it apart and tried spinning the motor while the armature was still in the housing and it was really difficult to turn it and it wasn't smooth either. The small bearing makes a massive noise too, as it's worn out.

Here's the mess I made. :P

CAM00868_zps0e6ee408.jpg

Edited by Davy

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