GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV
VW GTI MKVI Forum / VW Golf R Forum / VW Golf MKVI Forum / VW GTI Forum - Golfmk6.com



Go Back   VW GTI MKVI Forum / VW Golf R Forum / VW Golf MKVI Forum / VW GTI Forum - Golfmk6.com > Technical Topics > GTI 2.0T Engine / Drivetrain / Exhaust / Tunes


Reply
 
Thread Tools Search this Thread Display Modes
Old 07-03-2018, 01:11 PM   #1
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Clogged Catalytic Converter??? How to check

Edit* So not the downpipe, but more likely the exhaust manifold. Will update when solved.



I currently have a cobb catted downpipe on my car and I believe the cat is partially clogged. Had a bad boost leak last year and ran rich for quite a while. January of this year I got several stuck injectors while troubleshooting the boost leak (long story), fuel flooded the engine and I'm guessing ruined the cat. It's been fixed, but car doesn't have the pep it used to.

Current symptoms are:

Torque/power loss (not making peak torque till late in the power band)
Car feels sluggish and surgy down low
0-60 time is trash
Engine temps stay high
Lacks acceleration.
Exhaust sounds muffled
LTFT stay rich
Occasional rattle on start
Going up steep inclines I can feel the car struggling
MAF flow is less than I think it should be, ported stock turbo barely getting 200-215 g/s. @ 22+ lbs of boost

Reason I say partially clogged is because I still make full boost. Seems to open up after about 3k-4k rpm.

What would be the easiest way to confirm this short of pulling the downpipe all the way off the car?

Appreciate any advice.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |

Last edited by Stock-GTI; 07-08-2018 at 07:32 PM. Reason: Not the Downpipe
Stock-GTI is offline   Reply With Quote
Old 07-03-2018, 09:15 PM   #2
thatspsychotic
FIA GT Newbie
 
thatspsychotic's Avatar
 
Drives: '11 GTI 4DR DSG, '14 Forester XT
Join Date: Mar 2012
Location: Western MA
Posts: 743
Quote:
Originally Posted by Stock-GTI View Post

Current symptoms are:

Torque/power loss (not making peak torque till late in the power band)
Car feels sluggish and surgy down low
0-60 time is trash
Engine temps stay high
Lacks acceleration.
Exhaust sounds muffled
LTFT stay rich
Occasional rattle on start
Going up steep inclines I can feel the car struggling
MAF flow is less than I think it should be, ported stock turbo barely getting 200-215 g/s. @ 22+ lbs of boost


Reason I say partially clogged is because I still make full boost. Seems to open up after about 3k-4k rpm.

What would be the easiest way to confirm this short of pulling the downpipe all the way off the car?

Appreciate any advice.
Have you replaced your PCV? Honestly some of that sounds like a failed PCV valve. My car felt very similar to how you describe when my rear main seal failed due to failed PCV.

My theory on that is that the failed PCV presents a path from the intake manifold to the turbo compressor inlet by way of the crankcase. This makes it feel like a boost leak that doesn't actually throw MAF or too rich codes. And the extra volume in the crankcase that becomes pressurized by boost is additional volume that needs to be pressurized, as well as a boost leak, could also cause the weirdness in the lower RPMs.

I would think that a blocked cat would be less of an issue at lower RPM and more of an issue at high RPM, and I would have thought that the cat would get so hot that it could burn off pretty much anything. Who knows.
__________________
APR Stage 2 v2.4, Carbonio, Cast Downpipe | PTP Turbo Blanket | GFB DV+ | Unibrace UB | Tyrolsport Deadset | BFI Stage 1 Mounts | SuperPro Offset LCA Bushings | Enkei Raijin Gunmetal 18x8 et45 | Michelin PSS 245/35R18
thatspsychotic is offline   Reply With Quote
Old 07-03-2018, 09:22 PM   #3
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by thatspsychotic View Post
Have you replaced your PCV? Honestly some of that sounds like a failed PCV valve. My car felt very similar to how you describe when my rear main seal failed due to failed PCV.

My theory on that is that the failed PCV presents a path from the intake manifold to the turbo compressor inlet by way of the crankcase. This makes it feel like a boost leak that doesn't actually throw MAF or too rich codes. And the extra volume in the crankcase that becomes pressurized by boost is additional volume that needs to be pressurized, as well as a boost leak, could also cause the weirdness in the lower RPMs.

I would think that a blocked cat would be less of an issue at lower RPM and more of an issue at high RPM, and I would have thought that the cat would get so hot that it could burn off pretty much anything. Who knows.
Pcv got changed to latest revision last year. Turbo spools but slower than it should. I can hear a rattle from the downpipe area when driving at low speeds right after starting the car when cold. Found a thread on audizine with almost the exact same symptoms. Both his turbo and cat were shot.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-03-2018, 09:47 PM   #4
nevekd128
FIA World Rally Car Champion
 
nevekd128's Avatar
 
Drives: sf muni
Join Date: Sep 2011
Location: SFSU
Posts: 620
Quote:
Originally Posted by Stock-GTI View Post
Pcv got changed to latest revision last year. Turbo spools but slower than it should. I can hear a rattle from the downpipe area when driving at low speeds right after starting the car when cold. Found a thread on audizine with almost the exact same symptoms. Both his turbo and cat were shot.
probably have a broken exhaust stud/leaking exhaust manifold
__________________
MY12 gti with a f23t frankenthingy and man pedal transmission. Car rides sorta low for scene points
nevekd128 is offline   Reply With Quote
Old 07-03-2018, 10:03 PM   #5
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by nevekd128 View Post
probably have a broken exhaust stud/leaking exhaust manifold
I was thinking of that as a possibility or in combination with the cat going bad. There is a piercing whistle noise at moderate throttle. Sounds like a fizzle at full throttle. Doesn't always happen.

Do you think I could tell if it's the cat by dropping the midpipe and looking with a flashlight?
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-04-2018, 04:34 PM   #6
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by nevekd128 View Post
probably have a broken exhaust stud/leaking exhaust manifold
I think you are right exhaust manifold leak or broken stud would make the most sense. Hopefully just a bad gasket, stud replacement ain't cheap.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-04-2018, 08:54 PM   #7
zef
FIA World Rally Car Champion
 
Drives: 2013 GTI
Join Date: Dec 2016
Location: CT
Posts: 513
Beat the crap out of the car, park it and look underneath. If the cat is glowing red, it's clogged.
__________________
Check out my build thread here -> Build Thread

zef is offline   Reply With Quote
Old 07-05-2018, 12:41 AM   #8
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by zef View Post
Beat the crap out of the car, park it and look underneath. If the cat is glowing red, it's clogged.
So I'm guessing it's the exhaust manifold leaking. Because I just beat the mess out the car and the cat isn't glowing. Plus I doubt I could hit 24 psi and 140mph with it clogged. Plus just loaded a tune with more boost and hissing/whistling got louder.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-05-2018, 01:42 PM   #9
BudgetPhoenix
FIA World Rally Car Champion
 
Drives: 09 GLI
Join Date: Jul 2016
Location: Bay Area
Posts: 682
I'm curious about those other issues you have though if it was just an exhaust leak. I've dealt with multiple downpipe leaks, turbo gasket leaks and only got the occasional p2096 code along with exhaust smell and some extra noise like chirping and hissing.
BudgetPhoenix is offline   Reply With Quote
Old 07-05-2018, 06:58 PM   #10
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by BudgetPhoenix View Post
I'm curious about those other issues you have though if it was just an exhaust leak. I've dealt with multiple downpipe leaks, turbo gasket leaks and only got the occasional p2096 code along with exhaust smell and some extra noise like chirping and hissing.
Car is going into shop to check gaskets tomorrow morning. I'm guessing it's not just the leak causing the performance issue, car is still in the process of being tuned. Got a update last night w/ more boost improved acceleration, about topped out now @ 25 psi. Hissing and whistling under load got louder, occasionally hear the chirping. I partially attribute the engine temps to Texas heat and the amount of boost I'm pushing. Gonna put turbo blanket back on, now that I'm happy with wastegate setting. I think I lost some low end torque due to IE Intake manifold.

I'll update with findings tomorrow.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-05-2018, 08:03 PM   #11
thatspsychotic
FIA GT Newbie
 
thatspsychotic's Avatar
 
Drives: '11 GTI 4DR DSG, '14 Forester XT
Join Date: Mar 2012
Location: Western MA
Posts: 743
Quote:
Originally Posted by Stock-GTI View Post
So I'm guessing it's the exhaust manifold leaking. Because I just beat the mess out the car and the cat isn't glowing. Plus I doubt I could hit 24 psi and 140mph with it clogged. Plus just loaded a tune with more boost and hissing/whistling got louder.
Ah trip to Mexico I see
__________________
APR Stage 2 v2.4, Carbonio, Cast Downpipe | PTP Turbo Blanket | GFB DV+ | Unibrace UB | Tyrolsport Deadset | BFI Stage 1 Mounts | SuperPro Offset LCA Bushings | Enkei Raijin Gunmetal 18x8 et45 | Michelin PSS 245/35R18
thatspsychotic is offline   Reply With Quote
Old 07-05-2018, 08:33 PM   #12
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Quote:
Originally Posted by thatspsychotic View Post
Ah trip to Mexico I see
Well I do live in Texas so it's not that far away lol. Did another long pull today hit 150 going into 6th gear and still had some pull left. I wonder how long my turbo is last at current boost level, glad I have a spare sitting my garage. Need to port it though.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-06-2018, 07:43 PM   #13
Stock-GTI
Oval Newbie
 
Stock-GTI's Avatar
 
Drives: 2013 MK6 GTI
Join Date: Jul 2017
Location: DFW
Posts: 143
Well shop said no evidence of leak, I'm guessing I'll end up have to dropping the turbo and change the gasket just to be sure. Has to be the exhaust manifold. Downpipe checked out. The hissing and whistling only manifest under moderate to heavy boost and the car runs rich.

Gonna pull the pcv off first and check and reinstall. But car idles fine. No noises at idle.

On another note got tyrolsport caliper kit and stainless lines installed along with motul 5.1. Car brakes a lot better.
__________________
13 MK6 GTI CW DSG | Stratified | Integrated Engineering | Cobb | GFB | ARM | Forge | GruvenParts | Fluidampr | Neuspeed | TyrolSport | ECS Tuning |
Stock-GTI is offline   Reply With Quote
Old 07-08-2018, 05:29 PM   #14
zef
FIA World Rally Car Champion
 
Drives: 2013 GTI
Join Date: Dec 2016
Location: CT
Posts: 513
Quote:
Originally Posted by Stock-GTI View Post
Car is going into shop to check gaskets tomorrow morning. I'm guessing it's not just the leak causing the performance issue, car is still in the process of being tuned. Got a update last night w/ more boost improved acceleration, about topped out now @ 25 psi. Hissing and whistling under load got louder, occasionally hear the chirping. I partially attribute the engine temps to Texas heat and the amount of boost I'm pushing. Gonna put turbo blanket back on, now that I'm happy with wastegate setting. I think I lost some low end torque due to IE Intake manifold.

I'll update with findings tomorrow.

25psi? Did you go to a 3bar map sensor? Still on the stock map and considering swapping out for a 3. Boost is always safer than timing for more power.
__________________
Check out my build thread here -> Build Thread

zef is offline   Reply With Quote
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 12:46 PM.


Powered by vBulletin® Version 3.7.2
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.