MAF & MAP Sensor Cleaning & IMRC Valve Cleaning

[CJM]

Please remember to wear gloves when handling the cleaner solutions mentioned below

MAF SENSOR

The MAF Sensor is located here

Personally I removed the air-box, but you do not need to, to remove the MAF Sensor. However you will need to get/use a 5 pointed security torx with a hole in the middle, to undo the screws. I got mine from Ebay.

Once removed you need to use MAF cleaner, it is important to use MAF cleaner and not something like brake cleaner, as this could do damage to the plastics and possibly the sensor!.

Pic of the rear of the MAF Sensor

Firstly you need to clean the IAT sensor indicated by the arrow, spray the cleaning fluid on liberally, being careful not to hit the wire with the straw on the MAF Cleaner, ensure whole wire is cleaned.

Next in the middle of the sensor you will see a metal plate, again spray this liberally

Finally you need to clean the hot-wire (I think) which is visible at the end of the sensor,again spray liberally, be careful however, don't stick the straw from the spray in the recess. Apologies for the picture all you can see is the edge of some metal, however you should see a thin wire in-between, when looking at your sensor.

Now the most important thing, don't refit yet, leave to dry, I left mine to dry for a while and then used a hair dryer on a low temp setting to ensure the sensors were dry.
I also personally cleaned inside the air-box where the MAF Sensor goes.

MAP SENSOR (Including second IAT sensor)

The MAP Sensor is located here on top of the IMRC Valve.

It is fairly easy to remove just a 10mm bolt.

Pic of the sensor details

Pic of the sensor and where to clean

You need to liberally spray directly into the sensor cone and along the metal wire, then spray again into the cone with the cone facing down, so the fluid drains and flushes any debris out. After this concentrate on the yellow/orange bulge at the bottom, once satisfied that it is clean leave to dry, again I used a hair dryer on low setting to just ensure that all areas were dry.
When refitting the sensor ideally you should replace the "O" ring, either way coat it with some new engine oil before refitting.

IMRC VALVE

Pic of the IMRC Valve minus the MAP Sensor

The valve wasn't as bad as I thought it would be.
My personal advice is to ensure that the MAP sensor is removed before cleaning.

The valve is relatively simple to remove, however I was using a 12mm socket which I could do all but the top nut with, I ended up getting a 12mm ratchet ring key from Halfords, this would also make the bolt at the bottom of the valve, connecting to the support bracket a lot easier to remove.

Pic of the Valve removed

Personally I used brake cleaner sprayed on a rag to clean the oily sooty residue from the bottom chamber, and cleaned around the butterfly valve, (I took CJ's advice here on not removing the butterfly) I also cleaned inside the inlet manifold as far as I could reach.

On refitting make sure all metal faces are cleaned with brake cleaner on a clean rag.

After putting everything back together I took out the ECU Fuse for a couple of minutes and then replaced and started the car, with all ancillary s switched off, didn't touch anything and left for the ECU to learn for 10 minutes, then switch the engine off and then turned the ignition back to position II.

Since replacing the IMRC solenoid, which solved the major hesitation issues, however there has been 2 tiny judders as it is about 5mm into the temp zone and then all is fine.

Drove the car today and all seems well and so far no judders at all, early days and it maybe due to the ECU reset. :lol:

 

[F6HAD]

Carl, an excellent guide mate - really very very good :lol:

What did you clean the MAP sensor with?

Let us know if it cures your issues.. I might do this when I'm bored some time, looks like good proactive maintenance.

 

[CJM]

Carl, an excellent guide mate - really very very good :lol:

What did you clean the MAP sensor with?

Let us know if it cures your issues.. I might do this when I'm bored some time, looks like good proactive maintenance.

Fahad,

I used CRC MAF Cleaner, I got it from EBay

CRC MAF Cleaner

Powerenhancer sell it also, I think I recall you got some. I just didn't have anything else to order from them.

I've been doing some reading and it is advisable to do MAF cleaning as a routine maintenance, just think it is a bit daunting as it is so easy to mess up if your not careful. Some people have used brake cleaner, but they seem to be the ones who now have had to replace the MAF all together.

I think the main thing also is to ensure it is dry before putting back in, it's a quick job to do, but it takes a while to dry.

Will keep you posted on the issue, which isn't really an issue but rather a niggle, like I say it is 2 tiny judders/hesitations when just in the temp zone, then all is fine. I suspect it is the MAF as it seems a little more noticeable when the air is damp. The car is still much better since replacing the IMRC Solenoid, which was the biggest issue.

 

[F6HAD]

Yep I have some of that stuff but couldn't get my MAF off as I didn't have the right 5 pointed star torx... I've got one now in a new set I bought.. but like I said, I'll wait till I'm bored one day :lol:

Have loads of stuff planned for the mrs Polo this week, maybe next week now.

Keep us posted on whether you feel any positive effects from doing this.

 

[Ezhik]

Thank you, always good to see a detailed write up. I don't think the IAT is part of the MAF, it's my understanding its a separate part...

...the component on the MAF is a diode, and as far as I know just part of the circuitry, yet I'm open to be corrected.

 

[Gav]

Yip indeedy, that's just a diode dude.... :lol:

 

[CJM]

Thank you, always good to see a detailed write up. I don't think the IAT is part of the MAF, it's my understanding its a separate part...

...the component on the MAF is a diode, and as far as I know just part of the circuitry, yet I'm open to be corrected.

Yip indeedy, that's just a diode dude....

Ed, Gav,

The illustration shown is for the K20A6 engine, on the N22A the 1st IAT sensor is incorporated with the MAF Sensor and the 2nd IAT Sensor is incorporated with the MAP Sensor, or so I am reliably informed by the manual.

 

[Gav]

^^ Might well be pal, but it's still just a diode...

 

[Paul]

good write up Carl thanks for the info

mine has the same problem as yours on warm up but it doesn't do it every time

 

[joooe]

Great DIY!
When I have the time, I'll take a look at my MAP Sensor too.

 

[Ezhik]

Ed, Gav,

The illustration shown is for the K20A6 engine, on the N22A the 1st IAT sensor is incorporated with the MAF Sensor and the 2nd IAT Sensor is incorporated with the MAP Sensor, or so I am reliably informed by the manual.

OK, sounds reasonable, thank you for clarifying. I think it will be hidden inside near the hotwire in that case, won't it? Just wanting to be precise over its whereabouts for accuracy.

 

[CJM]

OK, sounds reasonable, thank you for clarifying. I think it will be hidden inside near the hotwire in that case, won't it? Just wanting to be precise over its whereabouts for accuracy.

Ed,

I was going off a diagram, which illustrates it at the rear and made the ***umption, unfortunately due to the illustration being copyrighted I cannot post on the open forum !

Like Gav and yourself say it could be inside, possibly accessed from the middle, although I did have a good look to see if there was any other area's requiring attention, plus the wire in question looks similar to the IAT sensor in the MAP sensor, sorry for any confusion. I still cleaned it anyway !!

May take it out again to have another look and see if I can clarify further.

I did try searching at lunchtime for some data sheets on the exact MAF, which seems to be on various cars, however unfortunately most of the sites were in German being Bosch.

 

[Monks]

Great DIY fella

 

[CJM]

Thanks Guys,

hope it helps someone someday !

Well some feedback on how the car feels since doing the job.

Yes it's early days so a lot of touching wood here but no slight jerking and "oh my" the car drives like a dream! (hope I haven't cursed it )

The engine sounds a lot quieter (not that it was a problem) , it seems to have lost or reduced the diesel rattle that was present when cold and the acceleration and general drive is silky smooth. The whole engine feels more flexible.

It sounds like it was bad before, it wasn't but driving it now it just seems even smoother.

I was reading up earlier on MAF's in general and quite often they tend to start to go in between 30k and 60k and cleaning only relieves any issues for a short period of time, so I'll have to wait and see. If indeed it was the MAF it could equally have been the MAP, especially with having the IMRC Solenoid issue.

Personally I think it is worth doing especially when you think that the hot wire is so fine and sensitive that any contaminants could easily throw the results out.

here's a link I found useful for anyone wondering how they work, I found this quite good as it also mentions the purpose of why there is sometimes an intake air temperature sensor built in
How sensors work

Also I found that you can get the MAF sensor itself for around £90 for genuine bosch, just put the part no. in google

 

[Ezhik]

It is a good write up, thanks,great detail you've gone too.

I agree with you cleaning it can only be a good thing. When I cleaned mine previously the first thing I noticed was reduced tick over when cold, my journey from home begins along 100 meters or so where about 10mph is the max speed, before cleaning I had to dip the clutch because it was too fast, after cleaning cold starting tick over dropped and I didn't. I used a slightly different method, I filled a small container, (OK yoghurt pot), with IPA (the alcohol kind, not the beer), and put the business end of the MAF in and made sure it was covered, shook it around a bit and left it overnight. I thought that way everything inside would get a good clean and IPA is safe on these parts, well mine was.

 

[CJM]

It is a good write up, thanks,great detail you've gone too.

I agree with you cleaning it can only be a good thing. When I cleaned mine previously the first thing I noticed was reduced tick over when cold, my journey from home begins along 100 meters or so where about 10mph is the max speed, before cleaning I had to dip the clutch because it was too fast, after cleaning cold starting tick over dropped and I didn't. I used a slightly different method, I filled a small container, (OK yoghurt pot), with IPA (the alcohol kind, not the beer), and put the business end of the MAF in and made sure it was covered, shook it around a bit and left it overnight. I thought that way everything inside would get a good clean and IPA is safe on these parts, well mine was.

Thanks Ed,

From my experience so far and how the car now drives, I am going to add this as a service schedule, possibly at every oil change, that way your getting the optimum driving experience!

Your method does sound good, as it gives it a good time to soak, did you notice much dirt in the pot afterwards ? Isn't IPA the main content in the MAF cleaners, I'm not well up on chemicals hence why I went with the sensor cleaner specifically for MAF's.
It also sounds a good method, especially for the guys that might be a little more cautious about handling the sensor with a can of compressed spray and a straw !

Did it take long to dry and where did you get the IPA from ?

Wasn't sure whether it was more the motion of the liquid removing the debris or the liquid dissolving the debris or a bit of both, don't know if you know a little more about chemicals, but it would be interesting to know.

Have you done your MAP sensor ?

 

[Ezhik]

There was some discolouration and little bits in the pot afterwards. I did keep agitating it every now and then, it was my thinking that it would soak into any crud and dissolve it. I used to use IPA at work a lot, mainly for cleaning video tape heads on broadcast VTRs amongst other things, its very inert and safe just on about everything, though I have seen it dissolve some kind of 'plastic' when not expecting it to, so nothing can be considered 100% safe without testing.

I think the cleaning is achieved by dissolving the build up, as you know the hotwire is incredibly fine and delicate. When I did the same job on my Audi a couple of years back you could see the hotwire through a gap in the MAF housing, I took a very close macro pic of it before and after and you could clearly see the difference. I did just have a look for them, but when I traded it in I cleared out all sorts of Audi stuff, including them pics.

I bought a 1 litre bottle of eBay, most economical way to get it, no home/workshop should be without. IPA evaporates very quickly and leaves no residue behind, it's one of its best qualities, so dries in no time, you can literally watch it evaporate off a surface in seconds.

Haven't done the MAP sensor...yet. After reading your guide only the cold weather has stopped me going out and doing it, I don't know why I didn't do it when I did the MAF, I think at the time I was trying to resolve a problem that the MAF might have been contributing to and didn't want to get sidetracked. It will get done now though, when that cold wind drops.

 

[CJM]

There was some discolouration and little bits in the pot afterwards. I did keep agitating it every now and then, it was my thinking that it would soak into any crud and dissolve it. I used to use IPA at work a lot, mainly for cleaning video tape heads on broadcast VTRs amongst other things, its very inert and safe just on about everything, though I have seen it dissolve some kind of 'plastic' when not expecting it to, so nothing can be considered 100% safe without testing.

I think the cleaning is achieved by dissolving the build up, as you know the hotwire is incredibly fine and delicate. When I did the same job on my Audi a couple of years back you could see the hotwire through a gap in the MAF housing, I took a very close macro pic of it before and after and you could clearly see the difference. I did just have a look for them, but when I traded it in I cleared out all sorts of Audi stuff, including them pics.

I bought a 1 litre bottle of eBay, most economical way to get it, no home/workshop should be without. IPA evaporates very quickly and leaves no residue behind, it's one of its best qualities, so dries in no time, you can literally watch it evaporate off a surface in seconds.

Haven't done the MAP sensor...yet. After reading your guide only the cold weather has stopped me going out and doing it, I don't know why I didn't do it when I did the MAF, I think at the time I was trying to resolve a problem that the MAF might have been contributing to and didn't want to get sidetracked. It will get done now though, when that cold wind drops.

I think seeing the dirt is a big plus about the method you used and I had a quick look on Ebay and the stuff is cheap to buy, it is the main content in the MAF cleaner also.

My theory behind the MAP sensor is that due to the issues with the IMRC Solenoid vac leaks that it was more likely to be contaminated, plus all the oily soot in the IMRC Valve was bound to have some effect on it.

I also think it is wise to reset the ECU when you have cleaned it as it maybe compensating for the dirty MAP/MAF sensor

Will be interesting to know if you notice any difference when you have cleaned the MAP sensor.

 

[CJM]

good write up Carl thanks for the info

mine has the same problem as yours on warm up but it doesn't do it every time

Paul,

So far so good, it hasn't done the tiny judder on warming up and is running much smoother than before.
Have you ruled out the IMRC Solenoid issue, with yours?

 

[Ezhik]

Just wanted to add another couple of comments. I took the MAP off and had a close look at it, obviously was very dirty due to its location. There are two sensors in there, one is pressure the other is temp. After thinking about it I'm not sure either of them will be effected by a bit of external crud on them. I soaked it in IPA anyway, and lots of black sticky muck came off. I don't think this falls into the same category as the MAF though, we know why getting dirty effects that and cleaning is proven to help. I don't reckon the MAP sensors are sensitive to getting mucked up, but I'm willing to be put right.

Its cleaned up and put back, but I don't expect to notice anything different.

What do you think Carl?

 

[Paul]

Paul,

So far so good, it hasn't done the tiny judder on warming up and is running much smoother than before.
Have you ruled out the IMRC Solenoid issue, with yours?

Not yet, I'll clean the other bits first as that's a bit cheaper mine is only a little judder and I don't get a MIL light come on

 

[CJM]

Just wanted to add another couple of comments. I took the MAP off and had a close look at it, obviously was very dirty due to its location. There are two sensors in there, one is pressure the other is temp. After thinking about it I'm not sure either of them will be effected by a bit of external crud on them. I soaked it in IPA anyway, and lots of black sticky muck came off. I don't think this falls into the same category as the MAF though, we know why getting dirty effects that and cleaning is proven to help. I don't reckon the MAP sensors are sensitive to getting mucked up, but I'm willing to be put right.

Its cleaned up and put back, but I don't expect to notice anything different.

What do you think Carl?

Found this tech data sheet on the web, granted not for our exact MAP sensor but it indicates the basic principle.

Bosch MAP Sensor

It states that it is resistant to fuels etc (obviously) looking at the sensor make up you have the pressure sensor at the top and the temp sensor below.

I would imagine if any part of the sensor will be affected it will be more the temp sensor as either the oily debris if left to build up on it, would insulate it and therefore throw off the reading. With the pressure sensor, looking at the diagram, if only the pressure connection is exposed and the glands are protected and sealed from the debris, then I cannot see how a pressure reading could be offset, unless the pressure connection was restricted (I imagine on a micro level the pressure connection travels upwards to elongate the etched pressure diaphragm, but that is just a guess looking at the diagrams. ) I cannot realistically see dirt effecting the pressure connection.

Now you mention it and you look deeper into it, it is more likely to be the MAF. Let me know what you think and whether you notice anything like quieter sounding or smoother drive.

I take it at the moment everything is well with your car anyway?

Have you ever cleaned out the IMRC Valve?

Again don't know whether this would realistically have any effect, although as a lot is going on in there perhaps it does have a small effect by absorbing some of the energy of the swirl and affecting it's motion, but it would only be the motion the mixture would I imagine still be the correct weight.

 

[Ezhik]

Found this tech data sheet on the web, granted not for our exact MAP sensor but it indicates the basic principle.

Bosch MAP Sensor

It states that it is resistant to fuels etc (obviously) looking at the sensor make up you have the pressure sensor at the top and the temp sensor below.

I would imagine if any part of the sensor will be affected it will be more the temp sensor as either the oily debris if left to build up on it, would insulate it and therefore throw off the reading. With the pressure sensor, looking at the diagram, if only the pressure connection is exposed and the glands are protected and sealed from the debris, then I cannot see how a pressure reading could be offset, unless the pressure connection was restricted (I imagine on a micro level the pressure connection travels upwards to elongate the etched pressure diaphragm, but that is just a guess looking at the diagrams. ) I cannot realistically see dirt effecting the pressure connection.

Now you mention it and you look deeper into it, it is more likely to be the MAF. Let me know what you think and whether you notice anything like quieter sounding or smoother drive.

I take it at the moment everything is well with your car anyway?

Have you ever cleaned out the IMRC Valve?

Again don't know whether this would realistically have any effect, although as a lot is going on in there perhaps it does have a small effect by absorbing some of the energy of the swirl and affecting it's motion, but it would only be the motion the mixture would I imagine still be the correct weight.

I did wonder about the temp sensor, it's not as if the temp is changing wildly and it it needs to keep up, it will be gradual and not sensitive to a few degrees. The sensor itself is insulated inside the plastic cover.

Mine was smoking badly, when a mate followed me he said it smoked every time I pulled away, even gently. When I put my foot down there were big clouds visible in the mirror, embarrassing amounts. At night could see the smoke reflected in the lights of the car behind me. I changed the solenoid and its filter and now I don't see any in the mirror at all, even under full throttle, but haven't had a chance to get my mate to follow me yet. I did have the occasional P2004 error, so know the solenoid needed replacing.

I haven't cleaned the IMRC or the EGR. I tend to think these parts are designed to work in that environment, I know they could get so mucky their operation could be effected, but I'm still going to leave them for now. I have no reason to suspect that is the case, I think they get mucky pretty quickly again after cleaning.

The MAF hotwire is the one that matters.

However, last week my wife said she could smell something 'burning', I had caught the odd whiff of exhaust now and then, and thought it might have the cracked manifold. The hot smell she mentioned was fumes, it was diagnosed yesterday with a cracked manifold. So I should get that done in few days, Honda Mountsorrel are only a mile away and they will put the claim in for me. It seems the cracked manifold also results in smoking, so I had two reasons to smoke.

It runs well enough, though I'm expecting it will be as good as it should be after the manifold is replaced.

 

[CJM]

I did wonder about the temp sensor, it's not as if the temp is changing wildly and it it needs to keep up, it will be gradual and not sensitive to a few degrees. The sensor itself is insulated inside the plastic cover.

Mine was smoking badly, when a mate followed me he said it smoked every time I pulled away, even gently. When I put my foot down there were big clouds visible in the mirror, embarrassing amounts. At night could see the smoke reflected in the lights of the car behind me. I changed the solenoid and its filter and now I don't see any in the mirror at all, even under full throttle, but haven't had a chance to get my mate to follow me yet. I did have the occasional P2004 error, so know the solenoid needed replacing.

I haven't cleaned the IMRC or the EGR. I tend to think these parts are designed to work in that environment, I know they could get so mucky their operation could be effected, but I'm still going to leave them for now. I have no reason to suspect that is the case, I think they get mucky pretty quickly again after cleaning.

The MAF hotwire is the one that matters.

However, last week my wife said she could smell something 'burning', I had caught the odd whiff of exhaust now and then, and thought it might have the cracked manifold. The hot smell she mentioned was fumes, it was diagnosed yesterday with a cracked manifold. So I should get that done in few days, Honda Mountsorrel are only a mile away and they will put the claim in for me. It seems the cracked manifold also results in smoking, so I had two reasons to smoke.

It runs well enough, though I'm expecting it will be as good as it should be after the manifold is replaced.

In respect of the temp sensor don't know whether it is mainly to pick up the change when the EGR opens and exhaust gases come in, so then mixture can be modified to compensate for the change and create a smooth transition.

Like you say I think the MAF is to blame for much of it, but all in all I think the whole hesitation issue is a combination of the IMRC Solenoid, MAF and cracked exhaust manifold and of course not forgetting the trusty fuel filter.

Interesting what you said about the smoke, mine still smokes on moderate acceleration but not all the time, so I suspect that part of that is a build up when driving in a high gear at low revs, as it is more of a cloud than continuous below.

I also think I need to keep an eye on the manifold, I have checked inside the engine bay, and haven't smelt anything major, but occasionally smelt diesel fumes in the cabin, mainly when stationery in traffic, so far I have put it down to vehicles in front and i am frantically trying to see if they are all diesels. It isn't all the time but maybe it is just starting, I'll have another look at weekend, certainly worth keeping an eye on with it being a known issue.

it certainly isn't as bad as when my Passat flexi bracket failed which joined the CAT to the turbo, that was like the car in front was IN the cabin !

Good luck with the manifold replacement, be interesting to see if you notice any other differences other than blue sky in the rear view mirror!

 

[Ezhik]

Carl, wanted to add, I think this has been a good discussion and I've certainly got more knowledge thanks to your research and input, and as we know, knowledge is power. Isn't this a good example of just one aspect of what the forum should be about, exchanging ideas, learning and building up a good knowledge base of accurate information.

Can I change the subject slightly to discuss ECU resetting which you touched on briefly earlier. I've always been under the impression that after the ECU has been reset, either by loosing power for short time, or by software, (I can reset through OBD software without having to loose power), then the learning which you speak of is a process that takes around 100 miles of driving, not just a few minutes sat with the ignition on. Certain parameters that the ECU adjusts, fuelling, timing, boost, etc etc, have a window, and as you drive it learns your style and gradually narrows those windows, saving these tweaks gradually over those 100 miles or so. So much so that if you took two identical cars and reset them both, one was driven very slowly and gently for the learning period and the other raced, you would end up with quite different performances out of them.

I've read your resetting instructions and wonder if I've got it wrong or did I misunderstand you? What do you think?

 

[F6HAD]

Guys all that resetting the ECU will do is default back to base values (for those values which are part of the self learning process) but you need to bear in mind the ECU is always learning.. it's not a case of resetting and then letting it idle.. The ECU will selft adapt with your style of driving all the time, and it needs to learn new settings at each point in the rev range which is why I normally tell people to give it a decent brisk drive for at least 50 miles following a remap.

 

[CJM]

Ed,

I got the info from the main pinned thread on slight missing or Hesitation from post #145 to #152. Waj suggested it as a way of resetting the ECU, the main reason was because I was still having two slight judders and it was suggested to reset the ECU just in case it was something that it wasn't self correcting for.

As Fahad has confirmed and you have mentioned the ECU seems to always be learning and correcting itself.
I mentioned to reset the ECU in order to clear any bad info that it was currently working to enable it to learn a fresh, with the clean sensors. the 10 minute idle is just from the information gained on the forum and I suspect that may fit in with some sort of ****ysis cycle performed by the ECU and then give the car the basics, after which the car will then learn your individual driving style.

If the thread read that after 10 minutes idle the ECU has learnt everything, then that was not my intention, I meant it was reset to the defaults. In all honesty if the "defaults" are stored on a ROM chip then I cannot see why the 10 minutes idle is needed either, unless it is to given the ECU a basic understanding on the individual engine characteristics on top of the "default" factory written basics.
Again given your explanation of the wide initial windows and the ECU tightening them as it learns, I would imagine it wouldn't matter much whether it was left to idle or not, but open to any advice on this.

I agree with you on the discussion front, personally I think your idea of soaking the MAF in IPA is a better way of cleaning it, which of course has come out of this, also I have learnt a lot more about the sensors. Like you say it is good to exchange ideas and it highlights one of the values of TA .

One thing that you maybe able to add, as you have worked with IPA quite a lot, is using your method is there any safety information such as use in a well ventilated area etc? As your leaving it overnight for example what about fumes / evaporation is there anything to be concerned about?

Cheers

 

[Ezhik]

I think as soon as as the ECU has been reset by whatever method, just start up and drive off. It'll be fine and learning will begin.

When I used IPA at work no precautions were taken, and we got it on the skin, it does dry out the skin but as far I know in small amounts nothing harmful or irritating, or maybe I'm just not sensitive to it. Its highly flammable and I wouldn't inhale large amounts or want to get it my eyes or drink it, but for what we are talking about just be sensible. A few cc in a little pot overnight won't harm, but don't leave it where it could catch fire, or rub your eyes when its on your fingers! Though I think if anyone wants 'proper' advice google will probably have it, but let common sense prevail.

 

[CJM]

I think as soon as as the ECU has been reset by whatever method, just start up and drive off. It'll be fine and learning will begin.

When I used IPA at work no precautions were taken, and we got it on the skin, it does dry out the skin but as far I know in small amounts nothing harmful or irritating, or maybe I'm just not sensitive to it. Its highly flammable and I wouldn't inhale large amounts or want to get it my eyes or drink it, but for what we are talking about just be sensible. A few cc in a little pot overnight won't harm, but don't leave it where it could catch fire, or rub your eyes when its on your fingers! Though I think if anyone wants 'proper' advice google will probably have it, but let common sense prevail.

Cheers for the info on the IPA,

Took the MAF out again today to have another look to see about cleaning inside, and gave it a quick once over with the cleaner just for good measure!!

Cannot see anything else that needs cleaning, looked in all the channels, so I think I got everything originally.

 

[CJM]

I've been getting P2004 & P2199 fault codes and found this post. I've bought some electrical ( non residue ) and some brake cleaning sprays. I don't have a security torx set , so not yet looked at the MAF unit. But this afters I took off the IMRC IAT sensor and here's what it looked like :-

Definately plan to strip off the IMRC valve to give it a blast!


Aslo, the Denso 446 Solenoid ( pre-face lift ), has a pull-off filter at the back. Can this be cleaned ????

Ian

P2004 IMRC Valve Incorrect Position

Most likely suspect is the IMRC Solenoid see this thread

Slightly Missing or Hessitation

P2199 IAT Sensor 1/2 Incorrect Voltage Correlation

The temps sensors are built into the MAP and MAF sensor on the facelift, haven't seen the pre-facelift so cannot for certain say they are the same but does the Denso MAP sensor have like a wire with a blob on the end of it in the tube part?


That MAP sensor looks pretty caked up, so the IMRC Valve could be equally caked up so well worth doing.

are you getting any other symptoms with it?

Oh you can get the 5 star torx on ebay, make sure you put 5 sided or star in the search

there is a link to a set here, you may find some cheaper

Ebay