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Malfunction Indicator Light (MIL)/Check Engine light

aj_law

Go Kart Champion
Malfunction Indicator Light (MIL)/Check Engine light - Cause: Carbon Buildup

Went off this morning on way in to work. 58K miles.

Stopped at local dealer and they scanned for codes/issues. Have a cylinder #4 misfire. What I saw on his laptop was a readout that had cylinder #4 registering a number in the 20s (26, 27, 28...) while the car was idling. Also noted a few small numbers in cylinders #3 and #2 as well, but they were low numbers, single digits. He said they were probably ghost or phantom misfires. Didn't seem overly concerned about them.

As you can see from sig, no engine mods. I did swap out plugs and install red top coil packs at 40K so I'd be pretty surprised if it's just a faulty plug and/or coilpack. Was thinking of buying new plugs, installing and swapping out original coilpacks to see if the issue goes away, but I didn't want to run the risk of masking a big underlying problem like an intake manifold so close to warranty expiration.

Have an appointment scheduled for Wednesday when they run a full diagnostic. Car has been pretty reliable to date (*knocks wood*) as I've only had to replace a water pump at 32K or so.

I'm figuring (kinda hoping) that it's an intake manifold. Have it replaced under warranty and have them do a carbon cleaning while they're in there. Think they said it would be an extra $260 to have the cleaning if they've already got the manifold apart.

Have people seen any other issues come up with a cylinder misfire? I'm most concerned about issues that wouldn't be covered under the powertrain.

I'm curious what most people have been experiencing when faced with this type of code. Reminds me, need to snag VAGCOM.
 
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aj_law

Go Kart Champion
Welp, turns out there's no mechanical issue...just need a good carbon cleaning. Biggest hit to the wallet possible. Great.

Can anyone recommend a place in the western Connecticut or Westchester County, NY area that does it at a reasonable cost?

Dealer wants a shit ton for the procedure...and that's after charging me $100 and change to diagnose the problem. The euro aftermarket place I've gone to for a few things is a couple hundred less, but I have to wait until next Wednesday and I kinda need it done before then.

Any suggestions would be much appreciated. Thanks.
 

aj_law

Go Kart Champion
Carbon Cleaning - 59K - Before/After pics

For those that are interested, had the service done at my somewhat local aftermarket euro shop. Ended up going to Speed Sport Tuning in Danbury, CT.

Reasonably priced. About a 5 hour job. Good people and they do good work. Car idles much smoother now. No hesitation at cold temps either. Feels like it pulls harder as well.

Here are some pics of the mess they had to deal with and what the valves looked like after some good, old fashioned elbow grease. The before shots are bad, but they're not terrible. I've certainly seen worse.















 
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aj_law

Go Kart Champion
Epic bump here.

Been dealing with some check engine lights for the last 6 months or so (about last 10K). Initially, codes were just misfires; occasional light came and went over the span of a few days. Most recently though, it came on and stayed on for extended period of time. Took it to my shop (again) that scanned it when it started and they told me I've still got misfire codes for carbon, but now I've also got a code for the intake (flapper or some shit?) too. Had the intake done under warranty by a stealership, so not surprised it's reared it's ugly head again.

Good news (I guess) is there's no labor charge for the intake replacement, just couple hundy or so in parts while they're in there blasting the carbon out.

[sarcasm]

Sweet!! Two for one deal!

[/sarcasm]

Anyway, will try to get some pictures of the carnage to see how things compare at this mileage to what it looked like earlier in its life.

Oh, and F Photobucket.
 

aj_law

Go Kart Champion
Turns out shards of my intake blew off and some of the pieces managed to find their way into the cylinder head?? One of the plastic pieces actually wore a groove in the head? Shop said they've never seen that before. There were no codes for low fuel pressure or anything so it will be interesting to see what effect, if any, it will have down the road. Shop said that there's a slight chance there could be misfires or fuel pressure faults down the road, but they didn't seem to be overly concerned about it considering I wasn't having them with an IM that went nuclear.

Anyone with any sort of experience like that?

Anyone with mechanical knowledge that can comment on that occurrence?

My mechanical knowledge is incredibly limited so the conversation I had with the euro specialist manager consisted of a lot of head nodding on my end with me acting like I knew what they were describing.

They removed everything from the older IM, cleaned out all carbon (wasn't as bad as last time), replaced fuel injectors and installed a new IM. Also had them change out the gearbox oil. I broached that topic. They didn't push it at all. Said it's considered a lifetime oil but when they do it, it's typically when the customer is north of 100k as I am.

Idles smooth as buttah now and pulls hard like she used to.

Wallet is considerably lighter tho. Couple bucks over a grand for everything.
 

GreyGti1990

Ready to race!
This is all pretty crazy. I'm located in CT as well but closer to Hartford.

I haven't done my carbon cleaning yet since I've owned the car and am probably due for 1 soon. I don't have any CEL's or issues with the car right now. But I've had it from 45k miles to where it sits now at 85k with no carbon cleaning.

Not even sure if the previous owner did a carbon cleaning but I know that he had the intake manifold replaced under warranty so maybe?

I'll need to find a shop to do the carbon cleaning. Did they walnut blast yours? Should i expect a $5-600 bill for it to be done?
 

zrickety

The Fixer
So this was your original manifold that finally failed?
I've never carbon cleaned...144k and running great. I do the occasional Italian tune up (30 min of 3k+ rpm driving), burns off deposits.
 

aj_law

Go Kart Champion
This is all pretty crazy. I'm located in CT as well but closer to Hartford.

I haven't done my carbon cleaning yet since I've owned the car and am probably due for 1 soon. I don't have any CEL's or issues with the car right now. But I've had it from 45k miles to where it sits now at 85k with no carbon cleaning.

Not even sure if the previous owner did a carbon cleaning but I know that he had the intake manifold replaced under warranty so maybe?

I'll need to find a shop to do the carbon cleaning. Did they walnut blast yours? Should i expect a $5-600 bill for it to be done?

Yes, manual scrub of the valves. Think it's in the 4-5 hour range.

The job runs around $600 beans or so depending on if the injectors need to be replaced or cleaned.

It's a haul from the other side of the state, but SS Tuning in Danbury does a fantastic job, doesn't try to up sell you and they know their shit backwards and forwards. These guys are experts in every sense of the word (been in business 30+ years) and know euro cars inside and out.

Like I always say about this topic on the GTI (for the most part), carbon cleaning isn't a matter of "if," it's a matter of "when."
 

aj_law

Go Kart Champion
So this was your original manifold that finally failed?
I've never carbon cleaned...144k and running great. I do the occasional Italian tune up (30 min of 3k+ rpm driving), burns off deposits.

No, this is my second intake manifold. First one was replaced under warranty by the dealer...as were my first two water pumps. Since SS replaced my last one, I haven't had any issues.

*knocks all wood within reach*

Dude, I have no idea how you've gone so long without having to do a carbon cleaning. I LIVE in the 3k-4k zone on a daily basis and still have buildup. I don't even really use 6th gear anymore. I do 6k pulls almost everyday and cruise at 75-80 on the highway in 5th. Totally shits on my MPGs, but doing what I can to mitigate buildup.

Maybe it's like ear wax; some people never clean their ears and they're fine while others produce enough to start their own candle factory.
 

gdub09

Ready to race!
I had an injector replace at 70k and had a cleaning. Just got the water pump replaced and looked at the valves, they're dirty again, not terrible but not perfect and I'm at 79K now.
 

GreyGti1990

Ready to race!
144k is really impressive lol. I'll probably be doing mine in the next year or so unfortunately, just for the peace of mind. I think I'll pickup a catch can as well. Maybe that'll help with a bit with less oil and crap getting in there. That and I don't want to blow my rear main seal that was already replaced once when I had my clutch done.
 
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