Misfire and running rough from cold?

4.2 V8 32v Naturally Aspirated - 414 bhp
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Lukes3
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Misfire and running rough from cold?

Post by Lukes3 » Sun May 15, 2016 10:33 am

Just a qwick one for you lads wht do you think?
From complete cold the 4 misfires an runs rough, once warmed up abit it runs perfect.

It had a lambda sensor fault bank 2 sensor 2 so i replaced it with new now there is no fault with it. Drive it From cold an he Engine light flashes few times then goes off VCDS just says random misfire.
It has also had new oem coil packs an plugs fitted all 8.
Any idea's?
Cheers.
Current-saloon rs4,Full decat Xpipe miltek,cold air feed,BMC air filter, TTS supercharged, MRC stage 3 L/C F/S,hell s+s brake lines,AP racing rotors + vagbremtechnic bells, kw v3s clifford 650mk2

Gone-audi s3 8p stage2+ with loba lo400 turbo.

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RichieRS
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Re: Misfire and running rough from cold?

Post by RichieRS » Sun May 15, 2016 1:21 pm

I've got exactly the same thing although my VCDS hasn't picked up a miss fire!!!.

When cold it pops and bangs and misses but as soon as its got some temp in it then all is absolutely fine.

To be fair I have had it since I did the CC in which I removed the flaps and added the JHM spacers so I put it down to this combined with the SAI as it hasn't been mapped to accept the mods yet!!

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Surrey Sam
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Re: Misfire and running rough from cold?

Post by Surrey Sam » Sun May 15, 2016 4:23 pm

Removing the flaps will cause less swirl/tumble, this could effect the cars engine running when cold and at low RPM. A misfire does seem a rather excessive result for flap removal though?
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RichieRS
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Re: Misfire and running rough from cold?

Post by RichieRS » Sun May 15, 2016 4:59 pm

Surrey Sam wrote:Removing the flaps will cause less swirl/tumble, this could effect the cars engine running when cold and at low RPM. A misfire does seem a rather excessive result for flap removal though?

Agreed Sam. I had heard that some people did experience a bit of lumpiness when cold but not to the extent of missfire. Tbh sometimes I can start her up when not used for a few weeks and she's fine, other times she will have a bit of a splutter but it's only under load and not at idle at any point!!!

coffey555
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Re: Misfire and running rough from cold?

Post by coffey555 » Sun May 15, 2016 6:00 pm

Could be a passing injector, I had number 6 cause me problems until I changed it. The plug gets a little wet causing it not to spark properly.
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Lukes3
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Re: Misfire and running rough from cold?

Post by Lukes3 » Sun May 15, 2016 8:41 pm

RichieRS wrote:I've got exactly the same thing although my VCDS hasn't picked up a miss fire!!!.

When cold it pops and bangs and misses but as soon as its got some temp in it then all is absolutely fine.

To be fair I have had it since I did the CC in which I removed the flaps and added the JHM spacers so I put it down to this combined with the SAI as it hasn't been mapped to accept the mods yet!!
Yep same as mine. Only needs to warm up a little an its fine. Very odd.
Current-saloon rs4,Full decat Xpipe miltek,cold air feed,BMC air filter, TTS supercharged, MRC stage 3 L/C F/S,hell s+s brake lines,AP racing rotors + vagbremtechnic bells, kw v3s clifford 650mk2

Gone-audi s3 8p stage2+ with loba lo400 turbo.

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RichieRS
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Re: Misfire and running rough from cold?

Post by RichieRS » Sun May 15, 2016 9:18 pm

coffey555 wrote:Could be a passing injector, I had number 6 cause me problems until I changed it. The plug gets a little wet causing it not to spark properly.

Did this only happen when cold?.

Yes Luke. Very odd mate. I thought the stage 2 might sort the issue as it would get rid of the SAI and take into account the flaps being removed but obviously you have that and are still getting the issue!!!!

Lukes3
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Re: Misfire and running rough from cold?

Post by Lukes3 » Mon May 16, 2016 6:05 pm

RichieRS wrote:
coffey555 wrote:Could be a passing injector, I had number 6 cause me problems until I changed it. The plug gets a little wet causing it not to spark properly.

Did this only happen when cold?.

Yes Luke. Very odd mate. I thought the stage 2 might sort the issue as it would get rid of the SAI and take into account the flaps being removed but obviously you have that and are still getting the issue!!!!
I mine has only recently started doing this. It was running sweet after the mrc map. I have managed to get a fault up an it number 6 misfire.
It is abit annoying though as i have just put 8 new plugs an coils in.
So ill be swoping that plug an coil to another cylinder an see what happends.
Current-saloon rs4,Full decat Xpipe miltek,cold air feed,BMC air filter, TTS supercharged, MRC stage 3 L/C F/S,hell s+s brake lines,AP racing rotors + vagbremtechnic bells, kw v3s clifford 650mk2

Gone-audi s3 8p stage2+ with loba lo400 turbo.

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RichieRS
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Re: Misfire and running rough from cold?

Post by RichieRS » Mon May 16, 2016 6:36 pm

Lukes3 wrote:
RichieRS wrote:
coffey555 wrote:Could be a passing injector, I had number 6 cause me problems until I changed it. The plug gets a little wet causing it not to spark properly.

Did this only happen when cold?.

Yes Luke. Very odd mate. I thought the stage 2 might sort the issue as it would get rid of the SAI and take into account the flaps being removed but obviously you have that and are still getting the issue!!!!
I mine has only recently started doing this. It was running sweet after the mrc map. I have managed to get a fault up an it number 6 misfire.
It is abit annoying though as i have just put 8 new plugs an coils in.
So ill be swoping that plug an coil to another cylinder an see what happends.

Very strange mate. Keep us updated with your progress in sorting this!!

coffey555
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Re: Misfire and running rough from cold?

Post by coffey555 » Tue May 17, 2016 11:42 pm

It mostly happened from cold startup but it would misfire if coasting down a long hill off the throttle from time to time.

Fast forward a few years and I sometimes get a flashing then solid engine check light. This time always number 3 along with number 1 now and again. Happens on both cold and warm starts but never whilst actually driving.

Normally happens after short local trips around town so suspect the plugs might be getting fouled from long idles without the carbon being burnt off at the high revs.

When the injector was weeping that plug was wet and black, almosty oily. The other plugs were dry with white/grey deposits on them so quite easy to spot.
Misano Red RS4 B7 Avant

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