MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: Tal001 on December 11, 2014, 07:44:14 pm

Title: Idle rev
Post by: Tal001 on December 11, 2014, 07:44:14 pm

Hi all

I have an issue where when the car is idle the revs go from 800 up to 2k. Today a engine light came on and a scan has shown P0171. This shows too much oxygen in the exhaust.

Any ideas?

I read it could be the DV or PCV?

Thank

Title: Re: Idle rev
Post by: lukemk5gti on December 11, 2014, 07:47:01 pm

Not the dv. A split would only cause loss of boost with throttle down.

Could quite possibly be your PCV. Rougly €100 to fix

Title: Re: Idle rev
Post by: GrayMK5GTI on December 11, 2014, 08:00:23 pm

PCV is a lot less than €100.

You can buy one for 40 British  pounds and even a child could fit one  :signLOL:

Title: Re: Idle rev
Post by: Tal001 on December 13, 2014, 11:49:27 am

Hi thanks for your replies

I tested the pcv by starting the car up and placing paper over the oil cap, the engine was sucking the paper in.  I Think the pcv is fine.

 Any ideas on what else it could be?

Title: Re: Idle rev
Post by: Saintsteve on December 13, 2014, 04:47:49 pm

Change the PCV.

£38 from a VW dealer.. That will be the problem.

Title: Re: Idle rev
Post by: lukemk5gti on December 13, 2014, 06:39:09 pm

Quote from: Tal001 on December 13, 2014, 11:49:27 am

Hi thanks for your replies

I tested the pcv by starting the car up and placing paper over the oil cap, the engine was sucking the paper in.  I Think the pcv is fine.

 Any ideas on what else it could be?

Would you not change hoses and gasket while your at it no? Total cost came to I think €70 and although I'd do it myself labour might bring you up anothe €30 for 30mins work