Let me start this post off by saying this… I am not a qualified mechanic/engineer or anything of the sort. I am however a qualified googler and boosted brainiac when it comes to cars. Me love em loads. (Clearly missed my calling).
Disclaimer: Seeing I live in South Africa, I will directly list some parts and stores that will be mentioned below. I am not at all sponsored by any of the stores or people listed. If you wish you could always mention Goku in the chats then maybe they can give me millions worth of free car parts.
If you are reading this post I already assume you got some sort of idea about VAG FSI engines. If not read more here. These engines were designed to give more power and more power. Simple as that. If you have watched Top Gear and/or The Grand Tour, say POWER with the Jeremy Clarkson voice then you know exactly what I mean, no to mention improved fuel economy (that’s the last time I ever mention fuel economy).
The engine works by injecting fuel straight into the combustion chamber where the big bang happens, this in turn gives more power per ignition blah blah blah... I really will not go into much detail about how these work because you can read about it here.
Just like many great things, these engines do have their own faults.
As mentioned the fuel is injected straight into the combustion chamber, thus it does not clear the backside of the valves like it normally would with engines that spray fuel behind the valves. This results in carbon build up behind the valves on the intake.
We have seen a lot of examples of this predominantly on the RS4 (4.2 v8 tfsi) like here, however there are a whole lot of 2 litre TFSI’s (Golf GTI + S3) with this issue, specifically on the 2.0 motors (read here).
You can delete the PCV (Positive Crankcase Ventilation) without a catch can but I prefer the catch can setup because the pressure can be pushed into the catch can, where as if there was no catch can the pressure is all absorbed on the crank case, and who knows where that will lead…
Between the camshaft and the HPFP is the cam follower. These engines require a high pressure fuel pump (HPFP), this is driven off the camshaft. This knocks back and forth from on the camshaft, thus causing wear on the Cam Follower. While this is a fairly cheap part to replace, the effect of not replacing this often leads to pieces of mental breaking off into the cylinder head and judging from my tone you can tell that is going to cost a few bucks.
There are various options to fixing this, in South Africa you can either get new HPFP internals from the likes of say.. Revo or Autotech and replace the cam follower with a roller instead. This is also a common mod for reliability and performance benefits.
Cam Belt, tensioners & Water Pump
The cambelt is often mistaken for the cam chain which can also fail… The belt is on the left side of the engine in the 2.0 motors (chain on the right side… Yes there is both). It drives some critical engine components and if it snaps it can result in bent valves etc, which means engine rebuild which is always big money. These should be replaced at least every 3/4 years to be safe. Audi recommend 180 000 km on the bwa engines but we all know this is sales talk. Do it every 90 000 or so to be safe, if not less in my opinion. Do the belt and tensioners and water pump for safe measure.
For replacement parts on these I recommend genuine parts from VW or Audi. I know guys who have replaced them with some aftermarket brands and after a while or when the engine gets warm they sound like a bag of spanners.
Coil failure seems to be something of the past, however I think it should still make it to this list as there are people who sometimes get misfires and they are not sure where to start. Well, start with the coils. Swap them around and if the misfire code stays with the cylinder then you know it is not the coil.
Standard coils these days are replaced with R8 coils, often red in colour. Depending who you ask there is no real gain in performance but rather durability. I have not tested these out myself, but as I said, depends who you ask.
The 2.0T FSI engines came with diverter valves that seem not to hold their own once they get some good boost. If you have a boost leak as you climb up the rev range, start here. There are some good after market DV around, most people fit the GFP DV+. Sounds good too.
Audi and VW often state that there is no need to replace the fuel filters on their cars however we know fuel is never as clean as it should be. Frequent replacement means less glug for fuel to flow past. I recently replaced the fuel filter on my car and I must say there was a bit of a noticeable difference. Mind you the date on my filter said 2008, 10 years of filtering dirt out of fuel.
These can occur due to a number of issues, however there is almost an unwritten rule of how to follow a misfire.
Start with a scan, once you can identify which cylinder is having the issue switch the coil on that cylinder with a coil on another cylinder. If the misfire continues switch the spark plug on that cylinder with another cylinder.
If the issue continues it can get a bit tricky. You will have to start playing with the injectors, switch them around and if the misfire does not follow the injector… Throw away the whole car... Your next option will be to do a compression test and judging by where we are in this diagnosis you can tell that it starts getting expensive now.
I mentioned the first place to start is with the DV if you have a boost leak. The next I would recommend would be to check if the charge pipe is securely connected then follow it all the way to the inlet manifold.
I have seen one or two cases where people mistook the whistle coming from the PCV for a boost leak. Now let me not get it twisted, the PCV should not be making any whistle noises, if that does happen I recommend getting a delete with a catch can setup. They are a bit more than just replacing the original PCV but the benefits are both far and wide. To diagnose if the PCV is bad, start the engine and pull the dip stick, if it comes out easy and the car is not huffing and puffing then it is all good.
These are not the only issues with these engines, however these are the most I have seen around forums, facebook etc.
I have mentioned a few common mods above, however there are real boys with big turbo engines and boy do they come alive when they get some good boost.
Lets start with the normal stage1, 2, 2+ remapping. I am going to go out and make some comments that will get some people heated but this I have heard from many people but not seen myself (Remember google…).
Easiest mod found on these engines these days are Downpipe, intake and stage 2 software, some go 2+ software. There are various off the shelve files you can remap to, the most recommended being Revo. However… A lot of people regard the map to be very drive-able but not giving as much power as other brands of software. I have not seen this myself however a quick look here.
The next common mod would be water methanol injection (WMI) systems, these I find very fascinating. A mixture of water and methanol is sprayed into the intake upon certain level of boost. This atomizes the air and cools it, thus resulting a nice bang in the chamber with some massive power gain.
Next big common mod is big turbos. Going big turbo however requires some internals, I don’t care what Pete says. I met a chap from somewhere I wish not to mention, he had a GTX280 strapped to the back of his 2.0 TFSI with stock internals. Car was pushing in the 300kw bracket… Did I believe him… If I was born yesterday maybe.
Let us not get side tracked, to go big turbo you need internals, more fuel and good software. There are a few threads on audi forums of guys journey into the big turbo territory.
If you are looking for some good quality products from South Africa for your next mod check out some of these guys, really proud to say I share land with them (Real South Africans will get this joke)
Rogue performance <- Downpipe and Exhausts
Fast factory <- Sexy billet aluminium valve cover + other things
Delarey racing developments <- Billet things + also sexy boost tap
EuroWorx <- If you in PE, check Amish & Sean out. Top lads. If you ask he can show you his sexy golf…
Power brake <- Brakes and things to stop a lot of nonsense