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Author Topic: Misfire under load and wot  (Read 3187 times)

Offline mesaosi

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Misfire under load and wot
« on: December 09, 2013, 02:49:24 pm »
A couple of months back while driving the car, cylinder 3 died on me and I had to limp home on 3 cylinders. After swapping around coil packs, I determined the coil pack was a dud and replaced it.

Car was running fine since, until about a week ago when I noticed that when I planted the throttle in 2nd gear or higher the CEL would flash from about 4k rpm on. There was no noticeable lose in power, change in sound or any misfires and usually the light would go out as soon as I let off the accelerator. Reading the ECU with Torque gave a pending Cylinder 3 misfire. Having a spare new coil pack around, I swapped that in, but still got the code. The last 2 days the CEL would stay on solid after I left off, and finally last night there was a noticeable noise and loss in power when I floored it. The noise sounded almost like a stuttering noise as. Lifting off again resolved the issue, and driving the car around the city this morning was fine, although I never accelerated hard.

It's had a new diverter valve, PCV and breather valve recently enough and the plugs aren't even a year old as is the fuel filter. Also recently changed the cam follower. I'm leaning towards the fuel injector, but I don't really want to have to pull off the manifold to swap around the injectors for testing sake.

Any suggestions?

Offline scopes

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Re: Misfire under load and wot
« Reply #1 on: December 09, 2013, 03:10:06 pm »
What plugs you running ?

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Offline mesaosi

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Re: Misfire under load and wot
« Reply #2 on: December 09, 2013, 03:30:37 pm »
They are NGKs. Not sure of the exact model/spec, but they were put in by a VW specialist so I doubt they're spurious/crap ones.

Offline SkyJawa

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Re: Misfire under load and wot
« Reply #3 on: December 09, 2013, 03:35:47 pm »
Could still be one of the other coil packs?  On all my VAG cars I've had if one goes I replace the lot as another usually follows!

Offline mesaosi

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Re: Misfire under load and wot
« Reply #4 on: December 09, 2013, 03:38:53 pm »
Could still be one of the other coil packs?  On all my VAG cars I've had if one goes I replace the lot as another usually follows!

Wouldn't cause a misfire on the same cylinder though, would it?

Offline scopes

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Re: Misfire under load and wot
« Reply #5 on: December 09, 2013, 03:56:07 pm »
Try OEM plugs  :happy2:
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Offline GrayMK5GTI

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Re: Misfire under load and wot
« Reply #6 on: December 09, 2013, 04:00:43 pm »
If the CEL has flashed then a fault code will be logged. Get it plugged into VCDS  :happy2:
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Offline Donx22

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Re: Misfire under load and wot
« Reply #7 on: December 11, 2013, 12:20:46 pm »
sounds like when i had a dodgy plug on the 1.8t, would blow itself out under load.
ed30 also did the sdame thing under load on cyl 3 until i changed all the coilpacks. but plugs where fine - hoewever it did misfirer badly aswell and was very audiable. i would swap the coilpacks around and see if it follows.

Offline xjay1337

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Re: Misfire under load and wot
« Reply #8 on: December 11, 2013, 02:38:55 pm »
You can log fuelling per injector in VCDS I think.. so you would be able to see injector rates. And as mentioned might as well replace/check the plugs at least.