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Misfires in all 4 cylinders at low rpm under load

Ash17

Passed Driver's Ed
Stock 2010 GTI DSG with 97k miles that I just updated the tensioner as well as all the chains and guides. Replaced the intake manifold with the new revision because I got the P2015 code and could see the actuator arm popped out. Also walnut blasted the intake valves as they were very caked up. I resealed the cam cover and replaced my oil pan because whoever had the car before me hit something the left a big gouge in the pan that wasn't leaking but it looked gnarly and I wanted to replace the oil pump chain so it had to come off anyways. All new plugs and R8 coils. Also did a noise pipe delete and used the tiguan charge pipe to the throttle body. Another thing to note is I swapped back to 5w40 liquimolly instead of 10w40 castrol that I used the last 2 oil changes.

First start after I put it all back together and we're all good with no added engine codes! Drove it only from home to work the next 2 days and it drove great. Decided to drive a little harder and further the following day on my way home from work and it pulls hard and sounds healthy, but when I was pulling into my garage going about 5 mph at about 1k rpm with really light throttle the car starts misfiring and jerking pretty bad accompanied by a diesel type unhealthy engine sound. Let off the throttle and the misfiring and jerking goes away and the engine sound returns to normal. Roll into my garage and before I turn the car off I try to replicate what just happened only in park. Plugged in my OBDeleven and was checking blocks 15 and 16 and anywhere from about 750 RPM to about 160O RPM under light throttle the car starts misfiring in all cylinders but will smooth out with no misfires if I bring the rpms above 1600 or so. At idle with no throttle the car doesn't misfire, only when held within the 750-1600 rpm range with light throttle. No engine codes at the moment. Turn car off think for a minute then turn it back on. Idles for a little just fine like before but now I can feel it misfiring with zero throttle input just sitting at idle and now I see codes start popping up. A P0314 cam position sensor circuit a P0300 random/multiple cylinder misfire and P0301,P0302,P0303,P0304 codes for a 4 cylinders misfiring 😬. Cleared the codes turned the car off and went in for the night. A little scared but still pretty confident my timing was right as I followed the procedure to the T and replaced everything with genuine parts. Also if my timing was off mechanically speaking like a tooth or 2 I would think that the engine wouldn't perform as well at it does at any throttle load and rpm above 1600 or so. Also driving the car the first 2 days I didn't experience the misfiring at all at low rpms under load until I drove a bit further and harder. The next day the car started just fine with no engine codes and no misfires at idle. Let the car warm up a sec a have the revs drop to about 780 and then with the car still in park applied light throttle to hold the rpms in the range between idle and about 1600 and no misfires. Back out, drive to work and car runs great and no codes pop up. Drive back home for lunch and pulling into my garage no misfires or jerking at all. Return to work an hour later car still runs great. Leave work for the day and need to run a few errands in town which will require a bit more driving around and low speed city driving than the commutes I just made on the highway to and from work. Pulling into the parking lot for a store and going about 5mph at the same very low rpms the car starts misfiring and jerking very badly again. I quickly park and the misfires stop and still no codes. Go into the store for 20-30 minutes, come back out car starts great and driving through the same parking lot at the same rpms absolutely no misfires.... hmmm. Get to the other store a mile a way or so through the city and no misfires. Park, go in that store for about the same amount of time, start car drive to the next store which is a little further away and now pulling into this parking lot the misfires and jerking start again at low rpms. Put it in manual to keep it in first to hold it above 1600 rpms and the misfiring stops and I find a parking spot. Still no misfires at idle. Shop there and leave to go home and the car doesn't misfire while leaving the parking lot like It just did 20 minutes ago but then after driving the car a few miles home and pulling into the garage it starts misfiring and jerking.

It's been 6 days since I initially finished the work and began driving the car and the symptoms are still exactly the same as described above. Car starts fine with no codes and runs perfect on short drives even when the temp gauge is fully warmed up, but on longer drives it will eventually start misfiring at very low rpms under load but smooths out above 1600 rpms or so.

Could this be an oil pressure issue? The screen in the cam bridge was almost entirely missing so I popped out what was left and did my best to locate the rest but couldn't find it. Oil pan didn't really show signs of the screen but what it did have was a terrifyingly big piece of metal about the size of the head of a tack. Wtf is that from??! 20210522_122755.jpg20210522_122743.jpgWhen I resealed the cam cover I noticed the cam girdles had some fine scoring. Could something like the missing screen be clogging the N205 valve and causing it to malfunction at low rpms once the car has been driven for a bit? Almost seems like something in the oil is eventually picked up on these longer drives that clogs something and causes low oil pressure at those low rpms which is making the VVT act all funky and what gave me the P3014 code. But then when the car sits for a bit the oil settles and the clog is relieved until the car is ran again and the oil starts to circulate and the clog forms again causing the pressure problem.

I only got the P0314 code once and it hasnt come back, haven't had any low oil pressure warning codes or anything pop up. Could this just be a failing N205 valve or cam magnet on it's way out?

One thing I think is important to note is that this low rpm misfire under load has happened with the same car before I did any of the timing or replaced the intake manifold, but it was much much less severe and random and after doing this work it has gotten much worse.

Really don't want to have to tear the car apart again without having a better idea of what could be causing this, if anyone could please give me some insight it would be greatly appreciated.
 
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Joe_Mama

Autocross Champion
Hmmm, sounds almost like a throttle body problem to me. I think your best bet is to record logs while driving in the hopes you can capture it for analysis.
 

Ash17

Passed Driver's Ed
I've considered it but I would think I would get a more throttle body related code. I don't know how to record logs while driving using just an OBDeleven with the app, not sure if you can. I've only used it to inspect certain blocks that I've seen other people use to diagnose similar problems.

Something I left out was that the tiguan charge pipe to the the throttle body that I installed for the noise pipe delete did have this webbed plastic screen on the end the went onto the tb. The original charge pipe with the noise pipe on it didnt have this plastic screen so I snipped it out with some wire cutters and made sure it was smooth before installing. I imagine it was to limit air intake into the throttle body and also maybe make the air less turbulent, but it seemed like it would restrict quite a bit of air so I decided to take it out. Cant imagine that would cause an issue like this especially something that's intermittent like this and not all the time, right ?

This is a pic of the plastic find I removed on the tb side.1k0-145-770-ah---.jpg
 
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Joe_Mama

Autocross Champion
You certainly can record logs with obdeleven.
 

Ash17

Passed Driver's Ed
Update: I've noticed that the interior lights like the ones by the sunroof, start to dim and flicker when the misfiring is happening. Does this indicate anything or does this just sound like more random symptoms ?
 

vdubnick

Drag Racing Champion
How do I do that ? Do you need to have the pro version ?
no, you go to charts... it was a pain to find, because it is not like the demo vid shows. you have to build the log each time tho, which is dumb when you are logging multiple parameters.
 

Ash17

Passed Driver's Ed
no, you go to charts... it was a pain to find, because it is not like the demo vid shows. you have to build the log each time tho, which is dumb when you are logging multiple parameters.
Ahh ok I'll have to look into it a little more, I'm pretty foreign to diagnosing using my OBDeleven so in not even sure which blocks to look at. Should I focus on fuel and oil pressure related things?
 

Joe_Mama

Autocross Champion

Ash17

Passed Driver's Ed
https://www.golfmk6.com/forums/index.php?threads/golf-6-gti-issue-car-jerking-on-take-off.384061/

^^ This guy had a very similar problem to you and it turned out to be a problem with his cam housing

As for recording logs, time to do some reading

https://www.golfmk6.com/forums/index.php?threads/gti-data-logging-compendium.251480/
I'll have to read about the data logging, as for the other post related to a problem with the cam bridge I have considered it because I noticed the screen was missing and couldn't locate it. Could be lodged in one of the passages in that actual cam bridge itself. Little hesitant to through down 250 for new one though just to see if it works, but it might come down to that.
 

Ash17

Passed Driver's Ed
UPDATE: I replaced the n205 valve and cam bridge and the misfiring and jerking is completely gone. Uncertain which one did the trick but I have a feeling it was something clogged in one of the oil galleys in the cam bridge that was causing low oil pressure which was interfering with the VVT. Hope this can help anyone with a similar problem ✌
 

Joe_Mama

Autocross Champion
Awesome. Keep rolling
 
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