Intermittent Power Loss Issue Whilst Driving - Mk5 GTi (only 10 months olds)

[vwrascal]

What fuel do you use mojo?

The reason I ask is because I have had this 'non-responsive pedal' before. I was on a long trip and could not find a shell garage anywhere, with the trip computer showing 10 miles left in the tank, I had to stop at a BP garage - I half filled her with Ultimate, 20 mins later I got the non-responsive pedal, this happened 3 times in the same journey.
Just before getting home (running low on juice again) I filled her with the trusty vpower and hey ho- never had this problem since, btw this all happened over a year ago.
ps. I was not driving hard on this journey, just cruising at low to mid revs then all of a sudden there was nothing, even if I pressed the pedal to the floor (I was worried) then after roughly 5-10 secs it would return as normal   

I am not saying it definately was the BP fuel but it did make me think   

[xxx_mojo_xxx]

Fuel wise I usually pick and mix between BP Ultimate, Sainsbury's Super, Tesco Super, and Shell V-Power.  I can't see it being fuel related... otherwise loads of VW customers would have complained en-masse.

The latest is that no faults were logged.  Some people have suggested that it would take a couple of miles for the engine ECU to adjust to the new DV.

I don't want to tempt fate - but there hasn't been a recurrence of the problem since the last posted incident.  I have covered over 3000 miles, most of which has been "energetic" acceleration, or cruising at 120 mph.

I do think I need to change the Forge DV spring though... I got two with mine.  Green for standard engines (currently fitted), and yellow for remapped engines.   

[xxx_mojo_xxx]

Touch wood - no recurrence of the power loss issue.  The replacement DV must have resolved it, and I guess the the engine took a while to adjust/calibrate to it.

I'm now going to change the spring in the DV to the yellow one. Apparently that's for remapped cars, rather than the green one.

Also going to install the BSH Stage 1 PCV fix - without the catch-can. Not sure what that does entirely...can't see it doing any harm.

 

[xxx_mojo_xxx]

Put in the yellow spring today...and boy does it make a difference to boost.  Loving it... 

The DEFI gauge peaks at 22 psi - which I'm assuming is good?

[xxx_mojo_xxx]

*** HELP REQUIRED ***

I guess I spoke a little too soon.  The sudden loss of power has started again...   

Now that I have the DEFI gauge I can see that the needle falls below 20 when idling or when I am not pressing the accelerator.  The needle is no longer stable - but ever so slightly fluctuates between 20 and 21.  Before it used to be rock solid at 20.

Recently I had a THS intercooler and AutoTech HPFP fitted... could it be something to do with that?  May be some boost pipes to/from the intercooler have not been fixed firmly?

Or has my DV gone, again???  Thing is, my DV is a Forge one...

Any advice on things to check would be really appreciated.

Thanks in advance.

[xxx_mojo_xxx]

*** HELP REQUIRED ***

I guess I spoke a little too soon.  The sudden loss of power has started again...   

Now that I have the DEFI gauge I can see that the needle falls below 20 when idling or when I am not pressing the accelerator.  The needle is no longer stable - but ever so slightly fluctuates between 20 and 21.  Before it used to be rock solid at 20.

Recently I had a THS intercooler and AutoTech HPFP fitted... could it be something to do with that?  May be some boost pipes to/from the intercooler have not been fixed firmly?

Or has my DV gone, again???  Thing is, my DV is a Forge one...

Any advice on things to check would be really appreciated.

Thanks in advance.

Anyone?

[joesgti]

Mate, i have the same exact problem and have for about 8 months! no fault codes are brought up with VCDS and as soon as you turn it off and start it again you have full boost again.

Its like the turbo goes into limp. Ive now reverted into killing my ignition (whilst driving sometimes) and turning it back on and were off again.

I also have the forge DV, i firstly had this problem when going to the nurburg ring last year. Steve said my car had logged an over boost so im thinking it may be over boosting and then going limp.

Im putting my pump on this week with new MAF and cam follower so il let you know if the problem persists, it only happens now and then but is frustrating as i have no idea what it really is. 

[MAT ED30]

are all the pipes from the dv on the correct way around?

[joesgti]

are all the pipes from the dv on the correct way around?

  would there not be a more dramatic outcome if this were the case?

[xxx_mojo_xxx]

Thanks for the responses guys... just to recap the trail of events the symptoms are identical to what happened before the Forge DV was installed.  The very first set of occurrences turned out to be the stock DV which had ruptured its rubber seal.  Apparently a  very common fault.

At this time I had a couple of faults logged - something around low or under boost.

More recently, it's happened with the Forge DV.  This is despite being led to believe that the Forge DV is pretty much immune to failure due to its mechanism and construction.

As my recent power loss happened at a leisurely 50m/ph on the M1 through road works I can't see it being an over boost issue.  Also, this time round no faults have been registered.

Recently I have had a HPFP and intercooler upgrade, and  also the cam follower changed as a precautionary measure whilst everything was open.  If it's not the Forge DV I suspect its a leaking boost pipe - as the vacuum pressure on the DEFI gauge has dropped below 20.  Being able to see this information alone in my opinion has paid for the gauge...it' a great diagnostic tool.

Current plan is to visit TTS this Thursday so they can have a look as they originally carried out all the works.  I'm also considering the latest rev. of  the VW diverter valve.  Some people reckon it's actually better than the Forge one.  If I can get this to work with my DEFI gauge then I may go down that route.

In any case I will keep you all posted on progress...and if you guys could do the same that would be great.  

[joesgti]

keeping my eye on this as its exactly the same as mine, sounds like it doesnt happen as much as yours though,

[xxx_mojo_xxx]

To eliminate the Forge DV I purchased yet another one...the VW rev. D one.  I sold my spare one only last week. 

Anyway, the change has not made an ounce of difference to the vacuum pressure.  TTSHop reckon the lower vacuum pressure is down to the intercooler and HPFP upgrades.  It also indicates that the engine is holding vacuum compression a lot better than normal.  Boost pressure on WOT is 22 psi, which again is supposed to be really good.

On a slightly different note, I did notice that the actuator in the new VW diverter valve kicks in quicker.  So boost pressure is made available a lot earlier than the Forge one.  The reaction of the VW diverter valve is certainly a lot more immediate.

Also got the induction kit changed to a Carbonio one...thought I'd try something different.

No recurrence of the isssue - even after thraping the car and red lining it on a spirited run over 15 mins... how bizarre? 

Any news from anyone else?

[stealthwolf]

Glad swapping the DV helped. Did you get the Forge pipes sorted?

[xxx_mojo_xxx]

Glad swapping the DV helped. Did you get the Forge pipes sorted?

Spoke to Forge yesterday...apparently they have disposed of all their existing stock and waiting delivery of a new batch.

I will have to wait 3 weeks...so probably an early April job.

[joesgti]

not had it happen to me since the pump went in, but have only done about 20 miles this week, maybe its the forge DV, ive had mine for about 2 years. Am tempted to try a stock DV.