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Author Topic: Boost issue!  (Read 2449 times)

Offline Davewilkins

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Boost issue!
« on: April 13, 2015, 08:43:09 pm »
Hi guys - so after replacing my spark plugs and coil packs tracking down a lumpy idle my car has now developed a very noticeable boost leak/problem. I have changed DV/PCV/plugs/coil packs/MAF/N75. Only mods I have is revo stg1 and a piper cross panel filter. I've got VCDS and I can see that car is requesting boost (2440) and only making 1340 so n75 is at 99%. No misfires now, slight timing pull but ok. Fuel trims at 0.8 and 11 which seems high. Oh and the lumpy idle is still present! Anything I've missed? Or am I going straight to intercollegiate hosed?
By the way it's a 2006 gti axx k03. Any help would be much appreciated.

Offline Davewilkins

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Re: Boost issue!
« Reply #1 on: April 13, 2015, 09:49:15 pm »
That's meant to be "intercooler hoses"! Lol

Offline Davewilkins

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Re: Boost issue!
« Reply #2 on: April 14, 2015, 05:25:47 pm »
Just in case anyone was interested thought I would check my 4 month old Rev d diverter valve and sure enough to it has disintegrated! Luckily kept my old Rev c so put that back in and car is brand new again! Got a photo of the valve but can't upload it. Shocking piece of engineering on VWs part really!!

Offline Andy-GTI

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Re: Boost issue!
« Reply #3 on: April 18, 2015, 01:33:58 pm »
Rev G or a GFBDV+ be the best options to replace the Rev C DV. Doing mine soon also. Glad you sorted issue.

Offline Davewilkins

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Re: Boost issue!
« Reply #4 on: April 18, 2015, 04:54:47 pm »
Yeah have rev g coming. Just gotta sort this rough idle out now!!

Offline Andy-GTI

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Re: Boost issue!
« Reply #5 on: April 18, 2015, 05:30:28 pm »
Is it shuddering? like through the whole car, worse when cold seems to lessen one heated through?

Offline Davewilkins

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Re: Boost issue!
« Reply #6 on: April 18, 2015, 06:58:06 pm »
No mines worse when warm mate. I've seen various soft miss fires on vcds across all cylinders but not enough to trigger MIL. My fuel trim is high ish at 11% so maybe leaking hose somewhere. Could be loads of things tho!

Offline Andy-GTI

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Re: Boost issue!
« Reply #7 on: April 18, 2015, 07:17:33 pm »
I really need mine on VCDS to see what mines doing, mine seems better once warm.

What VCDS you use, newbie to the mk5GTI, is it the same as a mk6 version?

with the fuel could it be fuel pump and follower related? more wear on cars mapped id assume.



Offline beetie

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Re: Boost issue!
« Reply #8 on: April 18, 2015, 07:42:48 pm »
Strange idle could be due to carbon build up in the head.

Offline Davewilkins

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Re: Boost issue!
« Reply #9 on: April 18, 2015, 07:48:29 pm »
Yeah that's on the list of possible things it could be. I've read a few how to guides and it looks pretty involved! I'm not a complete muppet with a spanner but this maybe slightly out of my league. Thing is - do you replace injectors at the same time to rule them out?

Offline Andy-GTI

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Re: Boost issue!
« Reply #10 on: April 18, 2015, 07:53:03 pm »
Strange idle could be due to carbon build up in the head.

May run a can of BG44K through mine see if it helps clean some carbon & injectors etc. Heard its decent stuff.

Offline Davewilkins

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Re: Boost issue!
« Reply #11 on: April 18, 2015, 09:54:20 pm »
I've just got the wynns direct injector 3 spray to use first.  Same sort of deal - spray through PCV hose whilst engine at 2k plus bottle in the tank. I don't hold out much hope but it's worth a try for £20.

Offline martin@gti.co.uk

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Re: Boost issue!
« Reply #12 on: April 18, 2015, 09:59:12 pm »
fuel additive wont work on head port carbon build up on tfsi / tsi

You might try some solvents via temp switch hole at intake manifold, but best thing is just take your inlet off and scrape it off, for best results.

Offline Davewilkins

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Re: Boost issue!
« Reply #13 on: April 18, 2015, 10:17:38 pm »
The cleaner goes through PCV or temp sensor hole for the inlet valves And then bottle in the tank for injectors. I'm doubtful it will work but worth a shot!

Offline Andy-GTI

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Re: Boost issue!
« Reply #14 on: April 18, 2015, 10:23:02 pm »
The cleaner goes through PCV or temp sensor hole for the inlet valves And then bottle in the tank for injectors. I'm doubtful it will work but worth a shot!

For the price it cant do any harm, so I agree its worth a shot!

Going to go for the PCV replacement on mine also as its not been done, and worth a go for the preventative measures also.

Will report back see if it sorts my idle out. Apologies for thread hi-jacking :signLOL: