boost cut out at the limit!what could it be?

**A80Avant** · 9 May 2006, 15:47

anyone?noone?
i did a search all around the site,but tell you the truth didnt find someone with this symptom before.All previous stutters other user cars have done where starting from low revs and low boost.Mine is apparent only at the end!!!Is this some kind of new symptom to look into??
cheers
Vasilis

**Bowlerwell** · 9 May 2006, 15:51

I had this problem, but I couldn;t be specific about the pressure...

I had very jerky motion on acceleration...

Cleaning my MAF sorted the problem. (there's a thread on it... check my posting history)
Diaphragm tear, boost leak, and WGFV ware also suggested to me.

***Greg_S*** · 9 May 2006, 16:23

is your car stock or chipped? as stock boost should goto 1.1bar on overboost but thats it

**alg** · 9 May 2006, 16:24

You really need to go over possible causes in order. Have you access to Vagcom ?
Get the codes if you can or follow other threads advice re 'blink codes' if you cannot source Vagcom.
Check, in no order
1 Any smoke white, blue, black from exhaust ? Can help identify cause
2 Check connections to WGFV (mine had a failing wire connection which was hard to spot initially..see my thread under MRC)
3 check MAF connections....try with MAF disconnected better or worse. Now RS2 is said to run without MAF but mine refused and just stalled
4 Could be really bad fuel and high temps but unlikely
5 Check DV ? what type are u using ? Check connections
6 Check for boost leak
7 Have you ever cahnged the fuel filter ???
8 Wastegate diaphragm tears seem to be unusual (not unheard of) which is good as you need a whole wastegate to replace IIRC and that costs

That should get you started.
Hope it helps

**A80Avant** · 9 May 2006, 17:51

Hello,
some answers :
My car is the RS2 with mtm chip that reaches 1.5-1.6bar overboost

Unfortunatelly some bad wiring from the beggining has disabled the vag com engine retrieval,thus i cannot check the codes!!!9i have bought a new engine wiring to replace but since its a pita job i havent done it yet)

1)No smoke coming out of anywhere,my turbo is brand new(RS2 original no more than 1500Kms done )

2)i actually id check the connections to the WGFV,only i havent tested the car after that.Indeed the samco hose is a bit tricky with the jubille collars there to keep everything intact.I re screwed everything tight...

3)Long ago i had mistakenly disconnected the MAF while the car was running and it probably took a fault code in and stuttered all the way.now it does nothing like that so unless the MAF has various symptoms when failing...I have never cleaned the maf before,nor the previous owner,but i dont think i have any IPA here.I may get a hold of some carb cleaner,but im a little reluctant to clean it with a spray,afraid to tear the sensor...

4)It is quite a rumor here with gas station polluting the fuel with water or other less clean fuel...i dont know...My injectors where recently cleaned as well.

5)DV is also new and original,changed only 1500Kms ago as well as my WGFV(again new and original)

6)How can a boost leak apear with all these samcos layin around???Also although i have a test kit,i dont have a garage near with really high air pressure to presurise the system(grrr)

7)fuel filter was changed on the last service around 4000kms ago...

8)so you mean i cannot just buy the diaphgram which is cheap and replace that????

thanks Alg!

**alg** · 9 May 2006, 18:10

I would wait until you can refill with a reliable fuel source. I find running the car stationary uses lots of fuel (if you want to use up the ? poor fuel quickly !!)

**A80Avant** · 9 May 2006, 18:18

i think i will be driving the car EVERYWHERE now!!! hehehe

also do you think i should give it a try and clean the maf carefully with the carb spray?

**maRS2** · 10 May 2006, 02:26

Use brake cleaner in spray can to clean the maf.
I do it since many years on the RS2 and on the Subaru before no problem

**Jeffer** · 10 May 2006, 07:44

Don't take for granted the samco's don't leak. Run a pressure test, then you know for sure. What fuelpump are you running? Ever replaced that or the filter?

**Jeffer** · 10 May 2006, 07:45

nevermind the filter question

I missed that in your previous post

**A80Avant** · 10 May 2006, 20:39

i cannot run the boost check due to the fact that there is no good power air pressure to produce a 1,5bar to hold on the pressure...

However,today i checked again,made a few boosts and it seemed to hold fine the boost without any rattling or stuttering...All i did from the day before was to tighten all visible jubillee clips.I must say that the samco hose going to the intercooler(the large s shaped one) could be a bit longer...it would help things a bit...

This is very annoying you know.I wish that it would either stutter or not!!!! Not both on and off!!!Could this be an indication of bad fuel though?Can i just rest on that???

I will also check the beru pipes,coil packs,i cannot check because i have no replacements(how much do they cost by the way?),im bringing my audi 200 MAF just in case,and also try to clean a bit mine.

Anyway,thanks for all the help.I will try to do a boost leak test,although i find it quite impossible for a samco hose to work well for only a month and then develop a tear!!!If something like that is an issue then i can respectfully say that those were an awfull purchase,but i highly doubt it...

i will keep you posted...

cheers!!!!!!!!!!!!

PS:By the way i have been treating lots of GB turists here in Crete....Please dont do fullish stuff during the night....after all the drinking!!!drink a bit lesss!!!!

**~~Corey~~** · 10 May 2006, 20:47

Originally posted by alg

8 Wastegate diaphragm tears seem to be unusual (not unheard of) which is good as you need a whole wastegate to replace IIRC and that costs

Sorry but you are incorrect, the diaphragm's do tear quite frequently and they are available on their own without having to buy the whole wastegate. You just need to know who to ask for one.

**alg** · 11 May 2006, 08:51

Originally posted by Corey

Sorry but you are incorrect, the diaphragm's do tear quite frequently and they are available on their own without having to buy the whole wastegate. You just need to know who to ask for one.

Fair comment however I was referring to posted solutions on this board which involved a replacement diaphragm. Not read any IIRC

Good to hear re replacement. Again had enquired in the past from vagparts when thought to be possible solution for a previous problem.

**A80Avant** · 13 May 2006, 13:04

Ok,
having only tested the fuel possibility(new parts for other options will be coming soon) i must say that i didnt see much improvement.I didnt have the time to run a lot as it is just one run after the refill.

I can say though that the idle is a bit ruff,and it seems that when i hit my mark for the boost to rise to the 1.5 level,it goes slower,as if it struggles to do so.It does seem that i may have a bad fuel pump,or a blocked filter at least,so i will be changing that but other than that,i will change my beru coil pipes,spark plugs,PCV valve etc.
how much do the ignition coils cost to replace?are they needed to be replaced?

cheers
Vasilis

boost cut out at the limit!what could it be?

boost cut out at the limit!what could it be?

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