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MK7 GTI shudders under hard acceleration

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
So what brings me here is my delightful MK7 GTI seeming to have an ignition issue (my best guess anyway) here's a break down.. It is a 2015 MK7 GTI S 2 door with the DSG with 65,000 miles. I currently am running a Stage 1 from Freektune and have a 3inch HiFlow dp as well as a cold air intake. When I first put the stage 1 my car was completely stock (just putting this incase it may be a cause, anything is possible with these cars) It ran phenomenal with no issues, I've had the tune for maybe 25,000 miles with routine oil changes and the dsg service done at 45,000 miles got the car with 31,000. Shortly after getting the dp on I started experiencing a issue where I would try to do a hard acceleration in 3rd to 4th and it sounds as if one of my spark plugs was clicking and it showed a Hyde Cylinder on cylinder 1. I checked the spark plugs and they were pretty bad to the point where one tips (not the core) was missing, I replaced with IKH24s and drove it to NH the next day with was 3 hours both ways. Car ran amazingly for 2.5 hours then it started doing it again. I pulled over, uninstalled the tune and it was fine on the drive home. The next day (still on stock) I drove 15 minutes to the store, did one hard pull and it did it again, at that point I just bought APR ignition coils. I installed those, checked the plugs, regapped and took for a test drive, wanna guess the result? Absolutely the same! I just wanna run my tune again pls help Thank you🤟
 

hans611

Lost
Location
Miami
Car(s)
'16 Golf R 6MT
These cars channel the majority of knock into the spark plugs... i think the hesitation is knock..... maybe the tune is too hot... what fuel are you using? Ill let someone smarter chime in....

edit: you said you hear clicking? that may be some really bad pre-ignition...
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
I'm using pump 93
Yeah but its only above 40mph and in 3rd and 4th, I floor it and it goes, then it hesitates and can maintain the speed but clicks while on the throttle after a certain point. I did a live log on it at idle, reved the car to 2000rpms and it said cylinder 2 had 11 misfires from the one second I was on the throttle, but I felt and heard nothing..?
 
Last edited:

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
Scope the cylinder of the one with the missing tip.
I'll open it up tomorrow morning and post an update after. But that doesn't explain 1 and 4. During the pull cylinder 4 dropped to -6.00 on the knock retard sensor, prior it had been around -3.00 which I read was normal.
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
UPDATE: I pulled the plug for cylinder 3 and found no tip -_-. It won't even throw any codes when the shudder does happen, it did before I changed the coils with and without the old plugs but for some reason now it doesn't, here are those codes.

Snapchat-903416394.jpg


Also if anyone knows how to remove the cobb so the dealer can't see its tuned please comment. I know how to unmarry it but I haven't found anything on it to see if that works otherwise I'd take it in with my remaining warranty.
 

Jose_Gti

Autocross Newbie
Location
Philadelphia
With the IKH24's I used to have misfires after 3k miles, switched to RS7 plugs and worked like a charm.
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
Thats what I initially had and they were amazing but I think I let them go to long considering the tip came off, burnt off or whatever happened to it. Maybe I fucked up gapping the densos idk but I just know its running the same as before I replaced them when that tip was missing.
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
Thats what I initially had and they were amazing but I think I let them go to long considering the tip came off, burnt off or whatever happened to it. Maybe I fucked up gapping the densos idk but I just know its running the same as before I replaced them when that tip was missing.
With the IKH24's I used to have misfires after 3k miles, switched to RS7 plugs and worked like a charm.
When you had the misfires when did they occur? Under throttle, at idle?
 

Jose_Gti

Autocross Newbie
Location
Philadelphia
RS7 came pregap I just checked the gap when I changed the oil every 5k miles.

I was having misfires some times at idle (but they were not too noticeable) but when I did a hard pull I got the check engine light, pulled the OBD11 to check live what was happening and I think it was cylinder 3 who was misfiring like sh!t. Changed the plugs and the coils worked for a while until the car started drinking oil more and more... Digs suggested to put the boroscope inside (I bough a cheap one from amazon https://www.amazon.com/Endoscope-In...t=&hvlocphy=9007224&hvtargid=pla-756962724414) the cylinder and sure enough you could see a white hair going up the cilynder.
I trade it in and that was it... no more black GTI welcome white GTI.
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
Damn man, how many miles did it have? I hope that isn't the case for my situation, I still have $16,000 to pay off and Cobb I'm pretty sure voids warrenty unless someone knows a way.. I'm waiting to get a new coil from apr and switching back from the densos to NGKs just to be safe because I know they're reliable. If that doesn't work then I'm looking towards HPFP because of how my AFR is dipping from 14.7 to 12.9 at times and when I came to a stop after the car started ticking under medium acceleration and died when fully stopped. After that possibly fuel injectors. If THAT doesn't work then I'll have to take it somewhere.
 

Jose_Gti

Autocross Newbie
Location
Philadelphia
Damn man, how many miles did it have? I hope that isn't the case for my situation, I still have $16,000 to pay off and Cobb I'm pretty sure voids warrenty unless someone knows a way.. I'm waiting to get a new coil from apr and switching back from the densos to NGKs just to be safe because I know they're reliable. If that doesn't work then I'm looking towards HPFP because of how my AFR is dipping from 14.7 to 12.9 at times and when I came to a stop after the car started ticking under medium acceleration and died when fully stopped. After that possibly fuel injectors. If THAT doesn't work then I'll have to take it somewhere.

It had 42k miles APR stage 2.

I did a pressure test (you can rent the tool at Autozone, pepboys) and numbers were good.
Most probably yours will be fine, I wouldn’t worry too much but for peace of mind I would buy a $20 boroscope to see what your cylinders looks like inside.
 

SilverMK7

Go Kart Newbie
Location
United States
Car(s)
MK7 GTI
I'm not too worried about getting that checked rn. I do know with APR that their tunes can be a bit more aggressive but I'm leaning towards heatsoak, fuel injectors and carbon build up. I placed an order for a CTS MQB DF IC to eliminate any heaksoak and since that was my next upgrade anyway. I was reading other forums that had similar issues to mine and they suggested Liquid Molly (Proline) Fuel System Cleaner and it completely got rid of the problem as well as the "normal" idle that sounds like a diesel, so I got one of those as well as their engine flush to go with the new oil. I'll update in 2 weeks after the IC get put on.
 
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