MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: waqasr on March 02, 2019, 11:48:29 pm

Title: Missfire, popping and cutting out at idle!
Post by: waqasr on March 02, 2019, 11:48:29 pm
Right guys, so car was running fine but thermostat needed doing as temps would drop on motorway. Changed out the thermostat  which was a horrible job and after all that I start the car and its revs are all over the place at idle and revs drop really low and the car ends up cutting out. Any ideas what it could be?
Title: Re: Missfire, popping and cutting out at idle!
Post by: MIJ_JAGGER on March 03, 2019, 12:15:46 am
Any fault codes?
Title: Re: Missfire, popping and cutting out at idle!
Post by: muff1991 on March 03, 2019, 02:03:17 am
Any fault codes?
Might be worth double checking everything you’ve took off and put back on when doing the job. Assuming you replaced manifold gasket tightened all bolts and plugged everything back in nice and snug etc.


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Title: Re: Missfire, popping and cutting out at idle!
Post by: waqasr on March 03, 2019, 10:29:37 am
Thats the thing no fault codes that point to it. Only low voltage as I removed the battery and that evap purge error which is to do with my decat I beleive as I haven't had it mapped yet.

I didnt remove the manifold, I removed the alternator to get to it but i did make sure everything was on properly, I fear ai have to take it all apart again :scared:
Title: Re: Missfire, popping and cutting out at idle!
Post by: muff1991 on March 03, 2019, 11:10:49 am
Thats the thing no fault codes that point to it. Only low voltage as I removed the battery and that evap purge error which is to do with my decat I beleive as I haven't had it mapped yet.

I didnt remove the manifold, I removed the alternator to get to it but i did make sure everything was on properly, I fear ai have to take it all apart again :scared:
My bad.. at 2 in the morning I don’t even know why I started finger bashing on Tapatalk (manifold... wtf) lol

Yes that’ll be the battery, I don’t doubt your diy... but we’ve all made stupid school boy errors on times so although it’s a pain, it must just be worth double checking everything (second time round will be easier and quicker too). I can’t see how the thermostat itself would have anything to do with the issue. But for the issue to arise immediately after the jobs been done says it’s a faulty or wrong part fitted, incorrectly fitted, something broke in the process or just a pure coincidence.

Some or all (im not sure) of the thermostat housings have a second temp sensor in the housing, did you have one in yours? Connected if so?
Also, just have a look around to see you haven’t caught or knocked any surrounding wires etc when doing the job.


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Title: Re: Missfire, popping and cutting out at idle!
Post by: waqasr on March 03, 2019, 04:31:50 pm
Haha no worries mate. So ive just been out and removed and refitted the throttle body charge pipe and checked IC pipes as it seems so much like an air leak issue, all piping was fine. Thermostat had one sensor on the lower pipe which I checked again and is fine.

However what I did find was that plastic pipe coming off the pcv ( the longer bendy plastic one which goes under the intake manifold) I gave it a slight tug and it was basically broken and came off, Im praying thats my issue, luckily I have a spare but not at hand. Will hopefully fit it tonight and report back!
Title: Re: Missfire, popping and cutting out at idle!
Post by: MIJ_JAGGER on March 03, 2019, 05:42:56 pm
That happened on mine while back but I got air leak fault code.
Hopefully replacing that resolves it
Title: Re: Missfire, popping and cutting out at idle!
Post by: waqasr on March 03, 2019, 09:08:09 pm
Just to confirm, replacing the broken pipe has sorted my issue  :laugh:. Though thinking about it now, the symptoms were almost the same as when you do a PCV check. Anyway happy days. Thanks guys.
Title: Re: Missfire, popping and cutting out at idle!
Post by: muff1991 on March 04, 2019, 08:49:15 am
Just to confirm, replacing the broken pipe has sorted my issue  :laugh:. Though thinking about it now, the symptoms were almost the same as when you do a PCV check. Anyway happy days. Thanks guys.
Nice one, it makes me think it’s worth checking mine as well just to be sure. I’ve heard they can crack or split quite easily. Glad you fixed it mate


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Title: Re: Missfire, popping and cutting out at idle!
Post by: waqasr on March 05, 2019, 07:23:38 pm
It was pretty cracked up so it broke damn easily. However I think I still have an airleak faulty somewhere. When cold and I start the car is still has a missfire ish kind of issue, slight judder until the revs drop to 750 and then it seems to drive a little jerky too. I think its time to refurb the injectors and do a carbon clean! Then its off to Rtec