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Author Topic: Poor idle  (Read 363 times)

Offline JASGTI

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Poor idle
« on: September 04, 2021, 11:31:31 pm »
So after spending the day doing the following
Cambelt kit
Water pump
Thermostat
Chain kit
Full service
Dsg service
Cam lobe
Alt belt
Alt tensioner

I now have poor idle, not enough to show on the revs but you can see and here it almost like it has cams in it.

Has a good pcv valve as swapped it with a perfect running one off another mk5 and it was still the same.

No light on but do have codes P2008 and P3138.

Do I need to perform basic settings on the inlet flaps as iv had the battery off for a day or two?

Any help please as was working fine before I did 'maintenance' .

Cheers Jason
Mk5 Gti, dsg 5door.

Offline colesey

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Re: Poor idle
« Reply #1 on: September 05, 2021, 07:32:43 am »
Air leak from cam cover gasket or dipstick?

Offline FJB

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Re: Poor idle
« Reply #2 on: September 05, 2021, 08:11:47 am »
My bet would be that you have disturbed the loom/connectors just underneath the flaps motor when doing the thermostat, easily done when moving the pipe bracket.

Offline Pudding

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Re: Poor idle
« Reply #3 on: September 06, 2021, 05:56:45 pm »
Yep, those codes do point to intake runner control and would definitely affect the idle quality.

You can run an output test with VCDS on the runner control motor and you can see the linkage arm moving up and down when all is good.  If no action there, you need to investigate the wiring.


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

Offline JASGTI

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Re: Poor idle
« Reply #4 on: September 06, 2021, 07:13:53 pm »
Yep, those codes do point to intake runner control and would definitely affect the idle quality.

You can run an output test with VCDS on the runner control motor and you can see the linkage arm moving up and down when all is good.  If no action there, you need to investigate the wiring.

Just carried out a basic setting test and it appears to be moving. After clearing codes and driving to work today still have p2008 and p3138.

Thinking it must be aur leak somewhere dip stick maybe as it's still got the old orange one, if not keep hunting for a leak. Can only be slightly ad the revs don't move on the dash and no eml lights on plus if you just rest your foot on the pedal it's fine . :thinking:
Mk5 Gti, dsg 5door.

Offline LC5F

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Re: Poor idle
« Reply #5 on: September 06, 2021, 07:52:01 pm »
The quick check for PCV leak is:
With engine idling, undo the oil cap, with a good sealed engine there should be vacuum resistance to pulling the cap off and once its off the engine will stumble.
If you have a leak there should be little change in the idle.

Offline JASGTI

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Re: Poor idle
« Reply #6 on: September 08, 2021, 07:39:41 pm »
Good evening

So iv just tried removing the oil cap and have plenty of vacuum and the idle gets worse.

Thinking I get a new pcv and both pipes, new rocker gasket and new dip stick. Anything else that could be leaking air?

If I fit a runner flap delete do I need to get it mapped straight away ?

Plan is to go to r tech eventually once iv got exhaust, intake, intercooler and internals for a stage 2+ but that will be more like this time next year.
Mk5 Gti, dsg 5door.

Offline Pudding

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Re: Poor idle
« Reply #7 on: September 10, 2021, 12:01:15 pm »
Doesn't need mapping straight away but you will very likely get a lot of misfiring during warm up, more so over the colder months, which will be annoying.





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

Offline JASGTI

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Re: Poor idle
« Reply #8 on: September 10, 2021, 12:55:54 pm »
Doesn't need mapping straight away but you will very likely get a lot of misfiring during warm up, more so over the colder months, which will be annoying.

Might leave that until next year then and concentrate on the idle issues first.
Mk5 Gti, dsg 5door.

Offline JASGTI

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Re: Poor idle
« Reply #9 on: September 26, 2021, 04:54:51 pm »
Good evening

So after changing the rocker cover, pcv and pipes it still ideas poor and hunting. So took the air box and MAF off reved it up a little and took it for a spin and its 99% better maybe just a little hint of it but nothing major. Should I be getting new MAF or is this pointing to something else?
Mk5 Gti, dsg 5door.