MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: ConorGTI on January 25, 2017, 08:13:45 pm

Title: MAF knackered?
Post by: ConorGTI on January 25, 2017, 08:13:45 pm
Evening all.

I've been taking readings for a couple of days now and Im having problems, vacuum seems to sit around -8.7 at idle    G/s is around 3.5 at idle.

Max boost around 12psi, and maximum g/s was 121 from 2000-6000 rpm in 4th gear.
It runs fine for a few days and has these readings, all power drops but still get the same readings! Annoying! Anyone have any ideas?

Thanks a lot
I'm getting fed up with the car now! ☹️
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 02:19:09 am
Unplug it and go for a run and if it drives better then replace the maf.

Have you checked you dv lately.
Title: Re: MAF knackered?
Post by: ConorGTI on January 26, 2017, 06:28:09 am
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
Title: Re: MAF knackered?
Post by: Dan_FR on January 26, 2017, 07:17:04 am
Vcds.....

Data logging.....

I doubt it's the MAF, but it is impossible to diagnose an issue with the limited information posted above. Find somebody with VCDS who knows how to use it so they can run some logs for you
Title: Re: MAF knackered?
Post by: ConorGTI on January 26, 2017, 10:12:53 am
Sorry mate I'm not sure what people need to know, do you know any body in the South Yorkshire area? Thanks
Title: Re: MAF knackered?
Post by: Dan_FR on January 26, 2017, 10:24:01 am
Since I'm South Wales...... No  :signLOL:

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?
Title: Re: MAF knackered?
Post by: lukemk5gti on January 26, 2017, 10:34:26 am
Take a look at this register to find someone nearby
http://www.mk5golfgti.co.uk/forum/index.php/topic,88875.0.html

As Dan said. Have you had your DV replaced? How to guide below:
http://www.mk5golfgti.co.uk/forum/index.php/topic,87824.msg893078.html#msg893078

I find they're very reliable cars and are very easy to diagnose but help us to help you, get it scanned, post the results here and someone will always help!
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 11:55:51 am
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
id check you dv firstly and try get some to get some logs as been said.
Title: Re: MAF knackered?
Post by: pudding on January 26, 2017, 12:28:43 pm
Was it holding 12psi from 2000-6000?

As the others have suggested, check the usual things - Split DV, leaking boost pipe O rings etc, update the PCV to the latest one etc.  There is nothing complicated about these engines.  All of the common post turbo boost related issues are cheap and easy to fix.

A bad MAF will usually show up at idle but your idle g/s reading is in the right ball park.  MAF will reduce as the load on the engine reduces, so we need to see some logs to analyse.  Log - MAF, Lambda, Lambda regulator, requested and actual boost pressure, requested and actual fuel rail pressure, ignition advance and the knock regulator.
Title: Re: MAF knackered?
Post by: Paradox1 on January 26, 2017, 12:30:17 pm
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.
Title: Re: MAF knackered?
Post by: ConorGTI on January 26, 2017, 01:17:53 pm
Since I'm South Wales...... No  :signLOL:

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?

Well that's slightly too far haha. I had the problem and replaced it with the gfb dv+ still exactly the same mate. The code I get is p0171, clear the fault then it reappears between 75-85 mile later.  Cheers
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 01:34:01 pm
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.
yes but he maf was unplugged sunny so it will  :happy2:
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 01:36:10 pm
Since I'm South Wales...... No  :signLOL:

Have you checked or replaced the factory diverter valve? Have you checked the fuel trims using diagnostic data?

Well that's slightly too far haha. I had the problem and replaced it with the gfb dv+ still exactly the same mate. The code I get is p0171, clear the fault then it reappears between 75-85 mile later.  Cheers
you have a boost leak
Title: Re: MAF knackered?
Post by: Paradox1 on January 26, 2017, 02:58:48 pm
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.
yes but he maf was unplugged sunny so it will  :happy2:

Thats what I just said idiot
Title: Re: MAF knackered?
Post by: ConorGTI on January 26, 2017, 03:56:33 pm
Chill out fellas!
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 04:01:01 pm
It drives fine for about 5 mile with it unplugged  then all power drops and leaves me with engine management light on, cheers
id check you dv firstly and try get some to get some logs as been said.

DV wont bring up a engine light unless its unplugged.

Maf will if the maf isnt operate above a certain level. its most likely sensor related than broken DV.

Get it scanned.
yes but he maf was unplugged sunny so it will  :happy2:

Thats what I just said idiot
:surprised: read what you typed dongle breath  :signLOL:
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 04:01:50 pm
Chill out fellas!
its all good mate I know the Gaylord  :grin:
Title: Re: MAF knackered?
Post by: ConorGTI on January 26, 2017, 04:23:47 pm
Alright haha. Anyway back to the car problems!!
Title: Re: MAF knackered?
Post by: r5gtt on January 26, 2017, 04:32:31 pm
 :driver: