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Model specific boards => Golf mk4 => Topic started by: Mrwebster on 13 August 2012, 11:40

Title: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 13 August 2012, 11:40
engine revs up fine, idles ok, when your putting it under load  like you want to overtake someone, it will jerk/buck and hold at 3000rpm, if you let off and back on again a couple of times it will boost up again fine but a bit rough,
this problem is intermittent, someitmes it drives fine then next time it will drive poor.

ive fitted,  4 new top quality plugs
4 oem coil packs genuine ones
new vw n75 valve

all the pipes are ok, i replaced one wich looked a little nasty with a genuine part,
its really anoying now as its unpredictable and unsafe to overtake people.

anyone have any suggestions? or do i keep throwing cash at it lol
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 13 August 2012, 11:42
also to add,   had it scanned a couple of times,  No engine light on, no codes,
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Wayne on 13 August 2012, 12:02
Well my Octavia vRS had the same fault, it turned out to be the maf had failed yet it never stored a fault code.

If your going to replace it stick with Bosch or genuine.

One more tip is to unplug it and try it, if all ok then you know that is the problem.
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 13 August 2012, 12:11
I unplugged it still the same dude
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: brianpologti on 13 August 2012, 17:06
also to add,   had it scanned a couple of times,  No engine light on, no codes,
Did you have it scanned by Vag com or a snap on one?
Some aftermarket scans don't show all the faults ,
I guess it will come up with 17705 , might be breather pipes under manifold ,
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: james2 on 13 August 2012, 17:08
I would check your dv or the activator thing on the turbo that opens the waste gate.  :undecided:
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 13 August 2012, 17:55
also to add,   had it scanned a couple of times,  No engine light on, no codes,
Did you have it scanned by Vag com or a snap on one?
Some aftermarket scans don't show all the faults ,
I guess it will come up with 17705 , might be breather pipes under manifold ,

Vagcom,  I'll change the diverter and check the actuator tonight
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 13 August 2012, 21:45
swapped diverter valve   no change   actuator on turbo is free and not stickeing * burnt myself in process*
  could this be a MAP sensor, problem
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: dan2252 on 13 August 2012, 22:34
if you buy a maf dont buy a gsf bosh one as it will last about 8,12 months, genuine everytime!
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 14 August 2012, 08:49
the MAF is fine,  i mentioned the MAP (boost sensor)
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Dalo Harkin on 14 August 2012, 09:03
They arent very common to go faulty, if its holding at 3,000rpm then its more than likely a boost related issue, recheck all the boost pipes again, remembering to look for oil
check the pipe after the pancake pipe (back of the engine) they are prone to leak/blow off
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 14 August 2012, 09:50
unplugged the MAP sensor, car runs smooth and goes past 3000rpm no problems, but on low boost obviously as its in limp mode,  anyone have a spare MAP as tps wanted £60!
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 14 August 2012, 10:50
Changed boost sensor  still not fixed,
Title: Re: Boost issues 1.8t AUQ engine,please help
Post by: Mrwebster on 15 August 2012, 16:18
New intake air temp sensor.  Still not fixed.