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Carbon cleaning done, still high rpm misfires... ideas?

GroceryGTIer

Drag Racing Champion
I spoke with UM a little while ago. According to therm, they don't believe it's a valve float issue, and he said tthey had not seen that. He said it was possible the car was running out of fuel, or any other number of things. I've read threads where people had this issue and it turned out the plugs were just not good for the tune so idk. There really is no point in taking the car to a shop and spend hundreds more that I could get on a trade. I don't have vagcom, so I can't log it and find out the issue, the shop is a an hour and 45 minutes from me, so I'm not doing that. At this point with an mk7 and a jb4 on 93, I'll make plenty of power, and just leave it at that.
 

thatspsychotic

Ready to race!
I don't think I'll part out much no, I'm sick of working on the car. The DP, intake, and CC I may sell, but I'm not digging into the front to get the IC, or taking the turbo off for a 3rd time... no way. A shame because that turbo is p&p with a forge WG on it. Motor mounts, etc.

Duuude even if you pay any local shop to swap those parts out and put the OEM back on, selling them will way more than make up for the shop labor, and you'll still get your trade value. It'd be a sad day for all those nice parts to get traded in.

Also, I don't buy UM's explanation at all, but we won't know without logs, and you're done with the car anyways, so whatever. There are several threads around here about K04 valve float, it is definitely a thing on unlucky cars.
 

GreyGti1990

Ready to race!
Any idea what it would cost to have the valve springs replaced? parts and labor?

I want to go k04 or slightly bigger eventually and am afraid of valve float lol
 

GroceryGTIer

Drag Racing Champion
Duuude even if you pay any local shop to swap those parts out and put the OEM back on, selling them will way more than make up for the shop labor, and you'll still get your trade value. It'd be a sad day for all those nice parts to get traded in.

Also, I don't buy UM's explanation at all, but we won't know without logs, and you're done with the car anyways, so whatever. There are several threads around here about K04 valve float, it is definitely a thing on unlucky cars.

I know, but im just so tired of working on the car, and in general paying money on it. I'd rather sell it outright for 13,500 with all the mods, if it's valve float, they'd get a car that could push likely 340-350 whp. Oh well...
 

GroceryGTIer

Drag Racing Champion
On a side note, should oil come out when I pull the filler cap off while the engine is running? Or is that yet another blown pcv?
 

thatspsychotic

Ready to race!
Any idea what it would cost to have the valve springs replaced? parts and labor?

I want to go k04 or slightly bigger eventually and am afraid of valve float lol

I think valve float issues are pretty uncommon, but if you did have issues I did a little searching earlier today and someone mentioned $500 worth of labor because with the right tools, the head doesn't have to be pulled to do the springs. APR's valve spring set runs $600.

I'd say do it if you want to do it, don't worry too much about the valves.
 

thatspsychotic

Ready to race!
On a side note, should oil come out when I pull the filler cap off while the engine is running? Or is that yet another blown pcv?

No idea because I've never tried that, not sure why you would...
 

Mk6 Steve

Ready to race!
If my wife’s due date wasn’t on Monday I’d offer to help you out and log the car. I’m in the same boat as you. New plugs, coils and rev d. Next is a new manifold and carbon cleaning since it’s never been done and I’m at 107k all highway miles. After doing a few logs I’m starting to suspect it’s either a throttle body issue or manifold/carbon/injector problem. I logged the misfire at around 5500 rpm and my maf was at 285 and never dipped, fuel rail pressure climbed to 169, but the throttle valve angle dropped to 92.5 although the accelerator pedal was steady at 99.2 throughout the pull that the misfire occurred. Injection timing dipped to 7.14 as well as boost dipped. Then everything thing recovers to normal. Any ideas gents??
 

GroceryGTIer

Drag Racing Champion
If my wife’s due date wasn’t on Monday I’d offer to help you out and log the car. I’m in the same boat as you. New plugs, coils and rev d. Next is a new manifold and carbon cleaning since it’s never been done and I’m at 107k all highway miles. After doing a few logs I’m starting to suspect it’s either a throttle body issue or manifold/carbon/injector problem. I logged the misfire at around 5500 rpm and my maf was at 285 and never dipped, fuel rail pressure climbed to 169, but the throttle valve angle dropped to 92.5 although the accelerator pedal was steady at 99.2 throughout the pull that the misfire occurred. Injection timing dipped to 7.14 as well as boost dipped. Then everything thing recovers to normal. Any ideas gents??

If I knew more about those types of specifics, I'd offer some sort of help, but I can't help much there. Congratulations on the soon to be arrived, that'll keep you busy for a whole. I actually suspect a bad o2 sensor being possible, but throwing more parts at it just doesn't make sense at this point.
 

zef

Drag Racing Champion
Valve float is only really an issue on GLI/CC cars and earlier MK6 GTI's. 12-14 GTI's shouldn't have this issue. There is a thread in here somewhere that shows you how to check which valve springs you have. There are 3 types that are marked with certain colors and stripes. 2 of the 3 won't work well with K04.

Is tyrolsport close to you? They're in NY and a UM dealer. Excelerate Performance in CT is a UM dealer as well.
 

GroceryGTIer

Drag Racing Champion
Valve float is only really an issue on GLI/CC cars and earlier MK6 GTI's. 12-14 GTI's shouldn't have this issue. There is a thread in here somewhere that shows you how to check which valve springs you have. There are 3 types that are marked with certain colors and stripes. 2 of the 3 won't work well with K04.

Is tyrolsport close to you? They're in NY and a UM dealer. Excelerate Performance in CT is a UM dealer as well.

Neither are close, but I'm not spending 1k or anymore money on the car for that matter anyway. My nearest performance shop that I trust is an hour and 45 minutes away, so not doing that either.
 

Mk6 Steve

Ready to race!
Thank you! I wanted to be done with all engine mods before the little guy arrives as I won't have time to get underneath it...as much...but this pesky misfire irks me. I would say a solid 75% of the times at WOT in 4rth gear I get a misfire or two. The other times I get a solid kick ass pull.
I installed a new O2 sensor with the K04 install. My readings during the same misfire log at WOT started off at 0.94 and by the end of the pull it held steady at 0.84 from 4,000-5840 rpm.
 

snobrdrdan

former GTI owner
There are 3 types that are marked with certain colors and stripes. 2 of the 3 won't work well with K04.



Thread & info is here, as well as how to inspect/check:
http://forums.vwvortex.com/showthre...SI-K04-MED17.5.2-Misfire-Issue-(GLI-CC-Passat)
 
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