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Author Topic: MK5 GTI Missfire issue ?  (Read 750 times)

Offline alexcon3

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MK5 GTI Missfire issue ?
« on: February 05, 2021, 05:43:23 am »
 Hi,
Really need help trying to solve a Missfire with my GTI 2.0tfsi manual BWA

My car has developed a Missfire on Cylinder 4.
I have changed plugs, coils and even the injector whilst changing the injector I did a carbon clean of the valves. Put the car together and idled and ran perfect for a couple hours and then started missfiring again.

It started missfiring ever since my mechanic installed the RS4 Fuel valve. But the car before that the idle east great but never missfires. Anyway when it started missfiring again after all that work I decided to remove the RS4 fuel valve and found out the mechanic either tightened it too hard or cross threaded leaving tiny tiny fragments of copper the funny thing thing is the RS4 fuel valve is closest to cylinder 4 injector.

So am I right to think that the copper fragments have entered the injector 4 and blown it and then blew the new Injector too ?
It's all weird. Driving as soon as u post 2-3 or even drive to 2-3k revs constant Missfire. And cold morning starts too always missfiring
Thanks.

Golf MK5 GTi 2.0 TFSI AXX

Offline mjmallia

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Re: MK5 GTI Missfire issue ?
« Reply #1 on: February 05, 2021, 07:32:46 am »
I would be plugging it into VCDS to see what it reports for all injectors and cylinders, but sounds like injectors if the carbon clean etc was done correctly.....I assume you used new seals on the injectors and new manifold gasket,  as they are supposed to be one time use.

I thought the RS4 valve was for stage two and needed a remap to take the extra fuel flow into consideration.

Does it pop and bang very loudly when mis firing?
« Last Edit: February 05, 2021, 07:34:38 am by mjmallia »

Offline DBXdarkangel

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Re: MK5 GTI Missfire issue ?
« Reply #2 on: February 05, 2021, 08:41:16 am »
As said above.. check the cylinder blocks on vcds and nail down what cylinder is misfiring. Then remove, clean or replace the injector. Same happened to mine.

Offline alexcon3

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Re: MK5 GTI Missfire issue ?
« Reply #3 on: February 05, 2021, 02:34:10 pm »
Cheers guys,

Cylinder 4 keeps missing. All new sparks plugs injectors. I'm assuming the copper fragments have destroyed the new injector. Ye all new gaskets and seals from TPS OEM. Compression test normal too.

I will borrow a mates VCDS and let everyone know what I find. The original fuel valve is back on now until I sort this issue :(

I will also be putting the stock map back on to see if it's the ECU.

I tried to use OBD Eleven to read injectors however won't let me read each injector
Golf MK5 GTi 2.0 TFSI AXX

Offline Pudding

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Re: MK5 GTI Missfire issue ?
« Reply #4 on: February 05, 2021, 07:30:47 pm »
That valve is proper mangled.  It's brass by the way  :smiley:

It's not unheard of for a coil driver to blow inside the ECU.  Pretty rare though.  Have you verified you're definitely getting a spark from coil no.4? 

You can't monitor the injectors with a scan tool apart from duty cycle, iirc, but that's across all 4.  They're not actually part of the DTC program.  The ECU just looks for a misfire using O2 readings vs crank angle, and it's up to you to find the cause, the old fashioned way!



2007 ED30 | Ohlins Coilovers | Revo Map | Plus some other stuff | Is all a GTI needs :-)

Offline LC5F

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Re: MK5 GTI Missfire issue ?
« Reply #5 on: February 05, 2021, 10:36:36 pm »
Have you done the basic test of moving No.4 coil pack to another cylinder to see if the misfire moves with it?

Injectors tend to have a replaceable mesh filter - if the brass has worked its way in hopefully it will have been caught in this

Offline alexcon3

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Re: MK5 GTI Missfire issue ?
« Reply #6 on: February 10, 2021, 09:12:14 pm »
Hi people,

I had my ECU sent for testing and come back all ok. Done all the tests new could new sparks moved coils the problem remained.

Quick update anyway the problem was indeed the small filing made its way to injector and blew it again.

So I've got new injectors and a new loom come with it. Will keep you all updated!
Golf MK5 GTi 2.0 TFSI AXX

Offline DBXdarkangel

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Re: MK5 GTI Missfire issue ?
« Reply #7 on: February 11, 2021, 08:46:28 am »
I did say it was your injector. Same thing happened to mine.

Offline alexcon3

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Re: MK5 GTI Missfire issue ?
« Reply #8 on: February 24, 2021, 08:20:17 pm »
I did say it was your injector. Same thing happened to mine.

Ye mate thanks. I purchased another set of injectors had then cleaned and flow tested and new filter baskets all come back good. Putting them on this Friday hopefully and will keep all of you updated just incase anyone gets the same issue
Golf MK5 GTi 2.0 TFSI AXX

Offline alexcon3

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Re: MK5 GTI Missfire issue ?
« Reply #9 on: March 01, 2021, 02:03:06 am »
UPDATE

Injectors changed for new ones and recleaned the valves. Problem is now solved and boosting like a rocket. Fuel consumption is amazing compared to before and no hesitations! Over the moon!

Thanks
Golf MK5 GTi 2.0 TFSI AXX

Offline Jons1001

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Re: MK5 GTI Missfire issue ?
« Reply #10 on: March 01, 2021, 06:33:09 am »
Great news that  :happy2:

Offline DBXdarkangel

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Re: MK5 GTI Missfire issue ?
« Reply #11 on: March 01, 2021, 09:12:27 am »
Whoop whoop  :laugh:

Offline alexcon3

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Re: MK5 GTI Missfire issue ?
« Reply #12 on: May 31, 2021, 07:23:12 pm »



Remember to check your DV valves people 😂😂😂😂
Golf MK5 GTi 2.0 TFSI AXX