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Model specific boards => Golf mk4 => Topic started by: harkerg on 01 December 2013, 23:24

Title: mk4 gti running issues
Post by: harkerg on 01 December 2013, 23:24
Ok so iv read through alot of this and iv been left confused.

I have a y reg 2001 gti 20v turbo the boost is intermittent jumps from 1 bar to 1.5 bar hesitates and backfires under load but does pick up but as stated earlier then the boost becomes intermittent.

Does seem to drive fine if I only give it half throttle n dont floor it I was under the impression it was the map because its over fueling fowling plugs with loads of black sutt and I can smell the fuel its strong smell even on tickover sometimes on tickover you can see the jet black smoke.

I dont know what this car has had done apart from cold air intake turbo back straight through pipe any help greatly appreciated to point me in the direction best to go down.
Title: Re: mk4 gti running issues
Post by: MoshiMoshi on 02 December 2013, 18:45
Try replacing (or unplugging at very least) the MAF sensor and see how it runs for you.
Title: Re: mk4 gti running issues
Post by: dom on 02 December 2013, 18:47
Ok so iv read through alot of this and iv been left confused.

I have a y reg 2001 gti 20v turbo the boost is intermittent jumps from 1 bar to 1.5 bar hesitates and backfires under load but does pick up but as stated earlier then the boost becomes intermittent.

Does seem to drive fine if I only give it half throttle n dont floor it I was under the impression it was the map because its over fueling fowling plugs with loads of black sutt and I can smell the fuel its strong smell even on tickover sometimes on tickover you can see the jet black smoke.

I dont know what this car has had done apart from cold air intake turbo back straight through pipe any help greatly appreciated to point me in the direction best to go down.

I've just replied in your other thread in the garage to do with turbos/engine codes :wink:

Try replacing (or unplugging at very least) the MAF sensor and see how it runs for you.

Definitely try unplugging the MAF, if running improves then the MAF is likely to be at fault.
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 19:17
Yea I need to delete other thread iv bought a new bosch maf n its runnin fine now but still has a boost issue fluxuating from 0.1 to 1.5 anyone give me an idea on this looks like its had an n249 delete
Title: Re: mk4 gti running issues
Post by: Scott D on 02 December 2013, 19:44
n75 valve, coilpack issue, lambda sensors

might be worth getting the ECU checked for any fault codes
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 19:57
Already sorted the misfiring problem mate just has a boost problem fluxuates from o.1 to 1.5 bar starts higher and always drops somtimes settles at 0.5 bar there was a code for n249 malfunction but from what I can see I dont have an n249 it confuses me to be fair
Title: Re: mk4 gti running issues
Post by: dom on 02 December 2013, 20:13
Already sorted the misfiring problem mate just has a boost problem fluxuates from o.1 to 1.5 bar starts higher and always drops somtimes settles at 0.5 bar there was a code for n249 malfunction but from what I can see I dont have an n249 it confuses me to be fair

That sounds perfectly normal, the boost should be progressive and won't be at full whack all the time. Mine peaks at about 20psi in 3rd and holds at 15psi. This varies depending on gear though.
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 20:20
Really? The difference is noticeable though and sometimes drops to the point it doesnt even feel like its boostin obviously goin from 1 bar droppin to 0.1 bar feels flat
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 20:23
Like itl go to 1.25 bar for example drop to 0.5 pick back up to 1 bar the completely drop off under load in the same gear
Title: Re: mk4 gti running issues
Post by: dom on 02 December 2013, 20:57
Like itl go to 1.25 bar for example drop to 0.5 pick back up to 1 bar the completely drop off under load in the same gear

Yeah, that doesn't sound right. Have you scanned for fault codes?
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 21:24
Iv had it on snap on reader and only fault code was for n249 mechanical malfunction but this has been removed as far as I can see
Title: Re: mk4 gti running issues
Post by: harkerg on 02 December 2013, 22:16
It had one code n it was for an n249 malfunction but as far as I can see its had a bypass done
Title: Re: mk4 gti running issues
Post by: harkerg on 03 December 2013, 11:08
No one got an idea
Title: Re: mk4 gti running issues
Post by: harkerg on 03 December 2013, 11:09
No one got an idea
Title: Re: mk4 gti running issues
Post by: barrym381 on 03 December 2013, 11:19
No one got an idea
is there not a vw specialist near you  :smiley:
Title: Re: mk4 gti running issues
Post by: harkerg on 03 December 2013, 15:00
Didnt think it would be able to go to vw with it been modded
Title: Re: mk4 gti running issues
Post by: barrym381 on 03 December 2013, 15:10
Didnt think it would be able to go to vw with it been modded
never meant the main dealer  :wink: were in the country are you
Title: Re: mk4 gti running issues
Post by: harkerg on 03 December 2013, 18:13
Northeast england
Title: Re: mk4 gti running issues
Post by: dom on 03 December 2013, 19:13
Northeast england

Where in the NE?
Title: Re: mk4 gti running issues
Post by: harkerg on 03 December 2013, 19:46
Near durham city mate about 20 mins from Newcastle