Golf 1.4 GT TSI Boost Problem

[scov1984]

I have a Mk5 Golf GT TSI (170). I am currently experiencing an intermittent fault whereby the Turbo is not boosting properley.

I can accelerate in 2nd, 3rd or 4th gear for example, foot to the floor and the car will accelerate as it should during the Supercharger "phase", but as it climbs above 3,000 RPM into the Turbo "phase", the boost needle suddenly drops from full bost to half boost even tho I am still at full throttle. I tend to lift off when this happens and as a test put my foot back down to the floor, this again only gives me limited power and the boost needle only goes to half way. It's like something is sticking or blocked.

The car is under warranty and has been in to VW Warrington twice with the same fault. They have changed the Recirc Valve (or so they tell me) and done a software update but I still have this intermittent fault. I know I can just keep taking the car back to VW under warranty but they don't seem to have a clue, there are no warning lights on the dash so it's as if they can't diagnose the problem and I am going to be wasting my time going back and forth to VW, so I'm attempting to diagnose the problem for them.

Sorry for the length of this post, just want to include as much info as possible.........So has anybody experienced a similar fault with the TSI twincharged engines? Or any suggestions as to what might be causing the fault?

Thanks in advance

[scov1984]

Anyone?.....

[CDPDesign]

Faulty Turbo? solenoid valve sticking? MAF sensor?

[sallyneale]

I think I am having the same problem with my TSI(140) . I noticed a "judder" when stationary (very subtle) and at the same time noticed that my Turbo didn't kick in at 3200 RPM - where it used to.
VW Cambridge have changed the Recirc valve, but the there is still a problem. They've now sent diagnostics to VW HQ, and it's booked in for 2 days next week for more tests.

It's all quite disconcerting....

Do let me know if you managed to get the to route of your problem.



QUOTE=scov1984;403274]I have a Mk5 Golf GT TSI (170). I am currently experiencing an intermittent fault whereby the Turbo is not boosting properley.

I can accelerate in 2nd, 3rd or 4th gear for example, foot to the floor and the car will accelerate as it should during the Supercharger "phase", but as it climbs above 3,000 RPM into the Turbo "phase", the boost needle suddenly drops from full bost to half boost even tho I am still at full throttle. I tend to lift off when this happens and as a test put my foot back down to the floor, this again only gives me limited power and the boost needle only goes to half way. It's like something is sticking or blocked.

The car is under warranty and has been in to VW Warrington twice with the same fault. They have changed the Recirc Valve (or so they tell me) and done a software update but I still have this intermittent fault. I know I can just keep taking the car back to VW under warranty but they don't seem to have a clue, there are no warning lights on the dash so it's as if they can't diagnose the problem and I am going to be wasting my time going back and forth to VW, so I'm attempting to diagnose the problem for them.

Sorry for the length of this post, just want to include as much info as possible.........So has anybody experienced a similar fault with the TSI twincharged engines? Or any suggestions as to what might be causing the fault?

Thanks in advance[/QUOTE]

[Crasher]

We had one in like this yesterday and the supercharger is failing, making a nasty noise.

[sallyneale]

I don't have a nasty noise - yet!

[DIMOTHY]

Sorry, I know this is an old post but, as I had this problem and managed to rectify it, I thought I'd post in case someone else has the same issue. I had it on a 56 plate 1.4 GT TSi and VW Caffyns in Haywards Heath sorted it.

They "Ran GFF Fault with N249 Recirculation Valve followed TPL 2016986/5, checked valve and found plug detached from plunger, requires replacement valve, refitted old valve and valve housing"

They then "Rechecked TPI and found fault relating to lack of power at 2800rpm, carried out software update and tested all OK, rechecked vehicle and found loss of boost pressure, further diagnostics found boost pressure regulator solenoid, replaced solenoid and road tested, fault no longer occurs."

Total cost was 180 quid and has worked a dream since. Apart from the drive chain jumping off, but that's another story...!

Hope it helps...

[sallyneale]

Thank you SO much. Mine is still with VW Vindis in Cambridge.
It's Day 10 (thankfully all under Warranty) They replaced the recirc valve last week, and remapped the ECU. it didn't fix the problem so they have been working with diagnostics with VW HQ (Milton Keynes and Germany) They've now found a clogged fuel injector - so are replacing ALL of them and cleaning the bores. They're doing the replacement now, and will then do a thorough road test to see if it fixes the lack of turbo (mine used to kick in at 3200rpm) and the "lumpy" on idle. I really hope this injector replacement fixes it. I only bought the car on 2nd December 2010 (Approved Used, 28000 miles). I want to have trust in the car again.

Thank you so much for your post.

[DIMOTHY]

No problems, hopefully yours will be fixed too. Just be careful if your drive chain starts to sound a bit clunky or starts jumping teeth - mine did, really badly and I had to trickle it into a nearby Bosch garage, where I was eventually told VW have made an updated part which minimises chain jump. VW were, naturally, cagey about giving out ANY details of this.

Can only assume the original part wasn't designed as well as it should have been, hence the modified version. Total bill for fixing that problem was £1100, which still stung even though I got £500 from the useless warranty company after a three month argument...

As for the lumpy on idle, I've heard loads about this with some people saying it's just a trait of the car and nothing to worry about. Please do let me know if VW HQ says something else - if it's an actual problem I'd love to find out so I can fix it!

[sallyneale]

Mine is an 07 plate - and I'll be sure to be listening out for ANYTHING that sounds odd!
Lumpy on idle. VW Cambridge are wondering if I got a bad batch of petrol...that has clogged one of the injectors. Is that likely?
I'm not hugely mechanically inclined - but I would like to know the connections (if any) with replacing all of the injectors and the likelihood of that fixing the missing Turbo. Any ideas? I noticed the lumpy on idle before the lack of Turbo boost. Mine would kick in at 3200 - but interestingly they told me last week that they had noticed a lack of power at 2800.

I've got VW to agree in principle - that if the injector replacement doesn't fix the problem - then it's on the table to discuss replacing the car. Or rather my partner has conveyed this to them!

What has upset me most - is that the communication initially from VW Cambridge was terrible, it's only after my partner got involved - and started being a bit hostile that they've sat up and started doing things. It's been unsettling to receive phonecalls when they said "we just don't know what's wrong - but we'll keep looking".....

I'll let you know if my Lumpy goes!