Author Topic: Bad misfire, help needed!  (Read 137 times)

Offline GTI_Kyle

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Bad misfire, help needed!
« on: June 19, 2017, 10:06:33 AM »
Need some help with a bad misfire on my stg2+ FL Leon cupra has developed. It starts ok but sounds really rough with a constant misfire, almost like a Scooby sound. It's in limp mode aswel with the EML flashing sometimes, plugged it in with my basic scanner & it come up as a misfire on cylinder 4 P0304 code.

Changed coilpacks & spark plugs but still same. I suspect maybe a bad injector or bent valves?

Anyone else had this problem?


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Offline Dan_FR

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Re: Bad misfire, help needed!
« Reply #1 on: June 19, 2017, 10:08:46 AM »
Very common, will be a duff injector..... Get someone with VCDS to look at the misfire to check its only that cylinder and that its a regual idle misfire that will probably clear up once revved..

Once confirmed, get it sorted ASAP and don't drive it about hard at all, as its a potential engine killer
TFSI... Revo Stage 2+... . WMI.... VCDS HEX + CAN, MPPS, VAG Commander & VAG tacho - South Wales

Offline GTI_Kyle

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Re: Bad misfire, help needed!
« Reply #2 on: June 19, 2017, 10:20:32 AM »
I had to limp it home but barely went over 25/30mph due to being so down on power. Hopefully it is just an injector and not bent valves!

Is there any particular reason why injectors give up?


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Offline Dan_FR

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Re: Bad misfire, help needed!
« Reply #3 on: June 19, 2017, 10:39:36 AM »
Common issue on the K04 engine cars....  Could just be carbon build up - ideally all 4 need to be tested and balanced.... R-tech offer this, whether you just send them your injectors or book in to have it all done for you
TFSI... Revo Stage 2+... . WMI.... VCDS HEX + CAN, MPPS, VAG Commander & VAG tacho - South Wales

Offline GTI_Kyle

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Re: Bad misfire, help needed!
« Reply #4 on: June 19, 2017, 10:57:08 AM »
I've had the inlet cleaned & RFD fitted recently mate so won't be carbon build up. Might consider sending them off once the problems diagnosed.

Is there any differences in symptoms with a bad injector & a bent valve?


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Offline GTI_Kyle

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Re: Bad misfire, help needed!
« Reply #5 on: June 19, 2017, 01:04:44 PM »
Update - compression test done & there is no compression on cylinder 4. Other cylinders are fine.

Once the heads off will have a better idea what the problem is...


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