FSI carbon buildup

PlasticMac said:
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.
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Will do the flaps too it’s a good call, anything else to check in respect of this one? I’d like to catalogue this together with other peoples FSI’s too (at different mileages) if they have an endoscope, sad I know but still, it interests me.
 
Visual of the actuator flap spindle linkage and return spring useful. Maybe visual of the actuator/linkage movement, while external vacum (a good suck on the vac tube) is applied. Use a clamp on the tube, once vac is created, to check integrity of tube and actuator diaphragm. If monitored with VCDS, full flap travel can be confirmed. Perhaps this should come first, to avoid unnecessary disassembly.
Mac.
 
PlasticMac said:
Visual of the actuator flap spindle linkage and return spring useful. Maybe visual of the actuator/linkage movement, while external vacum (a good suck on the vac tube) is applied. Use a clamp on the tube, once vac is created, to check integrity of tube and actuator diaphragm. If monitored with VCDS, full flap travel can be confirmed. Perhaps this should come first, to avoid unnecessary disassembly.
Mac.
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Cool, thank you.
 
Is it only the lower manifold that cokes up, or do both? Where does the EGR feed back before the manifolds, after the filter?
Mac.
 
PlasticMac said:
Is it only the lower manifold that cokes up, or do both? Where does the EGR feed back before the manifolds, after the filter?
Mac.
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EGR feeds directly into throttle body, after filters. The whole manifold assemblies carbon up, but only the lower manifold has the moving parts that gum up and seize. The engine management system orders movement of the flaps and when it doesn't see them move, then it puts up fault light.
 
Our Fsi engines have a simple construction compared to todays Audi 2.0 Tfsi with direct injection and injection in the intake pipe combined.

1578306024536.png
 
F89913E1-43B1-4C45-86D5-8458B6B298EB.jpeg


Thanks for the diagram. It makes interesting reading. Can you explain the high pressure and low pressure feeds more? The actual FSI pump as pictured above only has one input and one output.
 
steaman said:
Our Fsi engines have a simple construction compared to todays Audi 2.0 Tfsi with direct injection and injection in the intake pipe combined.

View attachment 60208
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Port and direct injection, port injection keeps the carbon buildup at bay whilst having the efficiency, power and emissions control.

I’ve read a bit about this and an interesting way to address the issue and clearly not something that could be retrofitted to an FSI.

It looks like keeping to the maintenance schedule, regular injector cleaner and 99 RON fuel is the only way to go. Once my endoscope camera turns up, regular monitoring and if the carbon build up gets bad then walnut blasting which will be circa 60k miles or when carbon build up dictates.
 
Jeetesh said:
Port and direct injection, port injection keeps the carbon buildup at bay whilst having the efficiency, power and emissions control.

I’ve read a bit about this and an interesting way to address the issue and clearly not something that could be retrofitted to an FSI.

It looks like keeping to the maintenance schedule, regular injector cleaner and 99 RON fuel is the only way to go. Once my endoscope camera turns up, regular monitoring and if the carbon build up gets bad then walnut blasting which will be circa 60k miles or when carbon build up dictates.
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That’s if I’ve read it right.
 
I've got 127,000 on an FSI and it's running absolutely perfectly at the moment. I think the flap was serviced at 75000 by the previous owner.

I've owned since 78000 and 2016 and run it on a mixture of 95 and 99 octane with liquimoly in the tank every 10k miles and so far so good.

Just had a fuel pressure sensor fail and had the egt sensor fail last year but other than that it's been trouble free for the last 49000 miles.

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markhux33 said:
I've got 127,000 on an FSI and it's running absolutely perfectly at the moment. I think the flap was serviced at 75000 by the previous owner.

I've owned since 78000 and 2016 and run it on a mixture of 95 and 99 octane with liquimoly in the tank every 10k miles and so far so good.

Just had a fuel pressure sensor fail and had the egt sensor fail last year but other than that it's been trouble free for the last 49000 miles.

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Good to know that there are plenty of FSI’s out there and relatively trouble free, there are some donkeys too however seems like poor maintenance have caused them early issues (no offence donkeys). 127k miles is a great number and long may it continue. I think the FSI is a fantastic engine and really suits the A2. Those that have never tried one, should.

Mine is early in its life (in terms of mileage) so tips for preventing issues is what I’ve been looking for, for that I thank you.

Is the liquimoly injector cleaner or valve cleaner that you use?..... or both? My current tankful has a dose of Wynns injector cleaner however that said my FSI is running fine so maybe didn’t need it.

I’m all about the prevention! ??
 
I use the injector cleaner. Just fill up the tank and then empty the bottle of injector cleaner into the filler cap.

Agreed the fsi is fantastic. Loads of power when you want to rev it and fuel economy that is still difficult to beat in a petrol car even 10 years newer!

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Hope it's okay to bring this thread back to life.

I have an FSI at 130k miles. I have fixed the flaps (actually looked fairly clean) changed the oil seperater and put in 4 new fuel injectors. I also have redone the timing belt.

I managed to get rid of all the engine errors but I have a lack of power. My friend has an old 1.2 1994 Peugeot 1.2 petrol. My car matched its acceleration on our latest trip. I couldn't beat it.

I am looking at trying a walnut engine clean but this lack of power does make me a little sad.

Do any of you have any advice before I try a walnut engine clean or does this make sence to give it a shot?

Many thanks,
Craig
 
One way of preventing EGR crud build up would be to remove the EGR pipe from the exhaust manifold, blank the manifold and fit a small air filter to the EGR pipe.
 
Somethings definitely not right there. I’ve got an FSI for sale here at the moment and it’s acceleration is great. Certainly more GTI like than snail.
 
A2Steve said:
Somethings definitely not right there. I’ve got an FSI for sale here at the moment and it’s acceleration is great. Certainly more GTI like than snail.
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It's nothing to do with "carbon" build up.
When you refitted the inlet manifold mechanism, did you lock the mechanism before reassembling (see pic)?
Then did you perform the adaptation using VCDS?
I find it very hard to believe an FSI that performs that badly would report no errors on a full VCDS scan.
What is the history? Did you buy it to sort it out, or have you had it a while, and it's gone down hill?
We'll help all we can, but need more to go on.
Mac.
 
Hi,

Thanks for the replies.

I have had the car for just over two years. It was a bit of a nightmare car but it's history was that it was at least a serviced car. Tbh the fastest way to see its history is my cars Instagram. Yeah I have one yes it's all for fun. @Project_audi_a2.

I know exactly the lock you're talking about on the manifold. This was locked in place on reinstalling the manifold. The work was done by someone else on the formus that I trust and he has already successfully done this job before on his own and other FSI's.

I have a full version of the vcds software myself, I have recently ran a scan with my only problems left to fix being my position flaps on the climate control.

What is this adaption run you are talking about? This is new information.

My car does still have the odd audible missfire too. As for the power it's always just felt off to me, it is now just rather obviously bad. It feels like the engine is straining and maybe even louder than normal when trying to get from 30 to 70 mph.

Any and all advice is as ever very much appreciated.

Edit: it's had all its belts a timing redone a few months ago. It was out by nearly two teeth. We did at one point get bad lifter sounds coming from the car. Weirdly only on the very day before it got its timing belt changed. This was done in an VAG garage.
 
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