FSI carbon buildup

[Jeetesh]

I’ve been doing a bit of reading around carbon buildup around the intake/valves with FSI engines as this seems to be a problem across direct injection engines in general.

Whilst my FSI doesn’t have this problem now, I can imagine at some point it will happen due to the design of direct injection engines. My reason for reading was to see if there were any tips for helping prevent or at the very least delay the issue.

From what I’ve read it appears that part of the solution that manufacturers have found is to add a turbo as the forced induction helps keep the valves/intakes cleaner for longer. This kind of explains why most VAG cars are TFSI’s now.

My reading led me to valve cleaners/walnut blasting and ultimately removal of the intake system to clean, the last two being the more expensive options which I may have to do at some point however really want to prolong anything like this so I’d start at valve cleaners.

I'm a bit sceptical about how much carbon a valve cleaner petrol additive (specifically Liqui Moly valve cleaner) would actually remove due to the design of FSI engines however I’ve come across this YouTube clip which suggests applying differently.

My question is therefore, what are people’s thoughts on this and has anyone tried anything similar?

 

[steveb]

In the old days we used to decoke an engine, take the head off clean the valves up etc. With leaner fuels you would expect this not to happen as much now....

 

[Jeetesh]

In the old days we used to decoke an engine, take the head off clean the valves up etc. With leaner fuels you would expect this not to happen as much now....

The issues with the FSI (to my understanding) is that because it’s direct rather than port injection, fuel additives that normally clean/reduce this from happening don’t reach the valves hence burnt oil causing the carbon buildup over time.

This is a widespread problem with direct injection engines and as mentioned partially solved with turbocharging. This isn’t something I’m planning on doing to my FSI so need to look at cleaning/preventative measures.

 

[oneflewover]

The issues with the FSI (to my understanding) is that because it’s direct rather than port injection, fuel additives that normally clean/reduce this from happening don’t reach the valves hence burnt oil causing the carbon buildup over time.

This is a widespread problem with direct injection engines and as mentioned partially solved with turbocharging. This isn’t something I’m planning on doing to my FSI so need to look at cleaning/preventative measures.

Normally only clean induction air would be going through the intake, automotive wisdom now sends exhaust gases through via the EGR, carbon via that is all that the build up can be. I will not advocate anything, however, it will not be happening on mine once i've got it off and cleaben. forum passim.

 

[Jeetesh]

Normally only clean induction air would be going through the intake, automotive wisdom now sends exhaust gases through via the EGR, carbon via that is all that the build up can be. I will not advocate anything, however, it will not be happening on mine once i've got it off and cleaben. forum passim.

Does the removal of the EGR impact emissions and therefore potential MOT fail?? How are you planning on cleaning?

 

[PlasticMac]

My impression is that the FSI (because of it's dual mode fuel/air control flaps) suffers from the build up of "crap" around the flaps. This eventually causes the flaps to become stiff and seize. Once the flap spindle losses it full close to open arc, the dreaded "Set Point Not Reached" error and EML warning are triggered. I agree the main source of the "crap" is the EGR system. Disabling the EGR system (venting to atmosphere) would largely solve the problem, but, for me at least, is not acceptable. Next best thing is to keep the engine in good condition by regular serving (and not driving for extended periods with EML on), and using only the best quality fuels, such as Shell V Power. The high octane rating, and detergent additives, reduce the "crap" produced during the combustion process.
Other than that, just accept that flap and manifold should be reconditioned after 80 - 100,000 miles. Surely, that's not so surprising is it? Many cars/engines don't last that long!
Mac.

 

[oneflewover]

Does the removal of the EGR impact emissions and therefore potential MOT fail?? How are you planning on cleaning?

Taking the manifold off to clean. Not sure about MOT, but it is easily reversible. Then as @PlasticMac says, if it only needs doing in another 50k miles, gee I'll probably be dead by then

 

[Jeetesh]

My impression is that the FSI (because of it's dual mode fuel/air control flaps) suffers from the build up of "crap" around the flaps. This eventually causes the flaps to become stiff and seize. Once the flap spindle losses it full close to open arc, the dreaded "Set Point Not Reached" error and EML warning are triggered. I agree the main source of the "crap" is the EGR system. Disabling the EGR system (venting to atmosphere) would largely solve the problem, but, for me at least, is not acceptable. Next best thing is to keep the engine in good condition by regular serving (and not driving for extended periods with EML on), and using only the best quality fuels, such as Shell V Power. The high octane rating, and detergent additives, reduce the "crap" produced during the combustion process.
Other than that, just accept that flap and manifold should be reconditioned after 80 - 100,000 miles. Surely, that's not so surprising is it? Many cars/engines don't last that long!
Mac.

Fully agree, I’m using Tesco Momentum 99 (whether it’s best or not I’m not sure but it has detergents in it), regular servicing with good quality parts (check), injector cleaner periodically (check).

I’ve heard this carbon buildup occurs between 30k-60k miles depending on how it’s been looked after, I’m on 26.5k miles and whilst my regime will be ‘to the letter’, I can’t speak for the two previous owners who did the first 25.5k miles.

One thing I probably want to do is find someone with an endoscope to be able to have a look. this might be the easiest way to check the level of build up, if any.

I do expect I’ll need to have it done, I just want any preventative/reduction solution along the way.

 

[Jeetesh]

Taking the manifold off to clean. Not sure about MOT, but it is easily reversible. Then as @PlasticMac says, if it only needs doing in another 50k miles, gee I'll probably be dead by then

I love the sense of humour........ rather like my own.

I notice you’re Leeds based (as am I), if you’re up for a coffee/beer at some point, I’d love to pick your brain on your A2/FSI experiences.

 

[PlasticMac]

.
One thing I probably want to do is find someone with an endoscope to be able to have a look. this might be the easiest way to check the level of build up, if any.

This would be a great idea. USB Endoscopes are not expensive, I've got a Lidl Special somewhere, last used it to find a bolt I dropped while changing the battery in my Mk1 TT. How much needs to come off to gain access (with a 'scope) to the manifold?
Mac.

 

[Jeetesh]

This would be a great idea. USB Endoscopes are not expensive, I've got a Lidl Special somewhere, last used it to find a bolt I dropped while changing the battery in my Mk1 TT. How much needs to come off to gain access (with a 'scope) to the manifold?
Mac.

I’ve ordered a cheap endoscope for my phone,” from eBay. eBay/Amazon have loads and cheap so if they turn out to be rubbish it’s not the end of the world. That said 2 megapixels and the ability to record in HD on the one I've ordered can’t be that bad.

I’ve yet to work out what I need to remove in order to be able to look in the manifold, that’s a job for another day.

My plan would be to remove the necessary parts and take some pictures, then periodically take more pictures so I can track carbon buildup, if I feel it’s excessive I’ll get something done about it otherwise it’s just an early warning sign.

Once I’ve tried, I’ll put a ‘how to guide’ together and post it (unless there already is one).

I’m all for picking up problems before they happen as the last thing I want is a breakdown when I least expect it. Hopefully with only 26.5k miles on the clock that should be a long way off (with this potential issue anyway).

 

[mrbroons]

I’ve ordered a cheap endoscope for my phone,” from eBay. eBay/Amazon have loads and cheap so if they turn out to be rubbish it’s not the end of the world. That said 2 megapixels and the ability to record in HD on the one I've ordered can’t be that bad.

I’ve yet to work out what I need to remove in order to be able to look in the manifold, that’s a job for another day.

My plan would be to remove the necessary parts and take some pictures, then periodically take more pictures so I can track carbon buildup, if I feel it’s excessive I’ll get something done about it otherwise it’s just an early warning sign.

Once I’ve tried, I’ll put a ‘how to guide’ together and post it (unless there already is one).

I’m all for picking up problems before they happen as the last thing I want is a breakdown when I least expect it. Hopefully with only 26.5k miles on the clock that should be a long way off (with this potential issue anyway).

I've got an endoscope also, this is what I used in my video in December to show the Vacuum actuator working. I'll try and slot this into the intake and see what I can see. Which reminds me I really need to get back on with Stob as it's not moved in weeks!! Hopefully I'll get time (and weather/light) this weekend.

 

[Jeetesh]

I've got an endoscope also, this is what I used in my video in December to show the Vacuum actuator working. I'll try and slot this into the intake and see what I can see. Which reminds me I really need to get back on with Stob as it's not moved in weeks!! Hopefully I'll get time (and weather/light) this weekend.

Just out of curiosity how many miles does Stob have?

It would be useful to see what level of carbon buildup you have and at what miles so when I get my endoscope I have a basis for comparison. Hopefully it will give me a idea of how the first two owners of my car looked after it and when I try some manifold cleaning techniques I can monitor progress (if any).

 

[mrbroons]

Stob has around 130k miles, so well in advance of yours.

 

[Jeetesh]

130k miles...... cool. What’s the life expectancy of an FSI?

What other than the air filter will I need to remove to be able to get the endoscope into the manifold for a quick look-see?

 

[mrbroons]

I can't see why an FSi will not go on as along as any TDi, technically when the TDi90 blows a VNT or DMF then it could be binned at that point but it's usually faithfully repaired even though the cost is circa £1000. It depends on what the car is worth to you how long it will last.

I'm going to go in via the air flow meter on the other side and see where I can get from there, hopefully not too many sharp turns if not then I may try in through the spark plugs to get a view of the cylinder crowns and see what crud is sitting there as an indication.

 

[Jeetesh]

I can't see why an FSi will not go on as along as any TDi, technically when the TDi90 blows a VNT or DMF then it could be binned at that point but it's usually faithfully repaired even though the cost is circa £1000. It depends on what the car is worth to you how long it will last.

I'm going to go in via the air flow meter on the other side and see where I can get from there, hopefully not too many sharp turns if not then I may try in through the spark plugs to get a view of the cylinder crowns and see what crud is sitting there as an indication.

I’m on quite low mileage and with an expectation to do 4k miles per annum it should last.

When you do go in can you send me some pictures so I can see or alternatively upload to your YouTube channel.

thanks in advanced.

 

[Andrew]

130k miles...... cool. What’s the life expectancy of an FSI?

I do keep a close eye on FSI sales on the Holy Trinity (sad really), and you see very few FSIs in excess of 150k. The highest I have noted on here is 240k (unverified) and another at 180k but these must be exceptions. There are no doubt others but probably kept going by loving owners who are strict on maintainance after a previous immaculate history of FSH. Any basic FSI over 150k, ignoring extras such as leather seats, is virtually worthless, say £250 as a breaker for parts.

I think you are too pessimistic about carbon build up on your low mileage example, although appreciate you want to minimise it, the mileage window for flap failure seems variable starting at 60k say, but not many get past 120k without 'set point not reached' failure. My view is the lower inlet manifold should be stripped and cleaned at 80k for preventative maintenance by the owner who wants to keep their FSI long term.

Interesting endeavour with the endoscope, look forward to a report.

Andy

 

[PlasticMac]

It is very likely that the crud that builds up in the FSI's inlet comes from the EGR system, and not directly from combustion. If that's the case, then (endascopic) visual checks will have to be done direct on the flaps. Carbon on the cylinder head and piston crown may not be an accurate guide to the inlet manifold. None the less, it would be very interesting to see a piston crown at 80+K, or 150+K even.
Mac.

 

[Jeetesh]

I do keep a close eye on FSI sales on the Holy Trinity (sad really), and you see very few FSIs in excess of 150k. The highest I have noted on here is 240k (unverified) and another at 180k but these must be exceptions. There are no doubt others but probably kept going by loving owners who are strict on maintainance after a previous immaculate history of FSH. Any basic FSI over 150k, ignoring extras such as leather seats, is virtually worthless, say £250 as a breaker for parts.

I think you are too pessimistic about carbon build up on your low mileage example, although appreciate you want to minimise it, the mileage window for flap failure seems variable starting at 60k say, but not many get past 120k without 'set point not reached' failure. My view is the lower inlet manifold should be stripped and cleaned at 80k for preventative maintenance by the owner who wants to keep their FSI long term.

Interesting endeavour with the endoscope, look forward to a report.

Andy

Weirdly Andy, I’ve started keeping an eye on FSI sales too, I’ve seen quite a few breakers at between 80k and 130k miles and not seen any at stratospheric mileages.

Ultimately I wanted an FSI as the 1.4 was too slow for me and diesels (especially euro 3/4) will be killed off one day, I also own a euro 6 diesel and and it’s probably cleaner than my FSI but politicians/councils don’t seem to know what they are doing. What I read prior to buying was it was higher mileage cars that were affected so it had to be a low mileage car, the other benefit was it’s was very good condition.

I agree, I’m being pessimistic however think it will be the sought after on one years to come hence trying to look after it. When the time comes I will spend mine on it together with the ongoing maintenance and 99 octane fuel.

Endoscope - I’ll definitely setup a thread with pictures periodically, I’ll also keep inspecting the other FSI foibles too. I’m grateful for the experience on the forum as you guys have been fantastic in upskilling me. I’ve learnt more in 2 months than I ever expected.

thank you