hi guys,

 

i have had this problem since i got my car, i didnt know it was a leak till i read this thread. it happens when i press the clutch and when the rev needle goes back down to below 1k, it carries on going down to 500 then backup again just like the OP. 

 

i did ask my mechanic and he told me it would be a big job so then i left it, it turns out it goes back to normal when i pull the gas pedal up (by putting my foot behind the pedal and pull it towards me).

 

i will have a look at where the leak is then try change the pipe, hopefully i can fix it.

it seems the OP car is same as mine:

 

heres some pictures of my engine, the bit the op pipe is taped up, mine is ok so no idea where the leak is, will need to have a proper look/hear.

 

 

Edited 15 March, 20215 yr by froggy8

Unless there's a massive obvious hole that I think you'd have noticed when taking the pictures I'm not sure that pictures of your engine bay can help people diagnose your problem (I may be wrong though as I am definitely a novice to all this).

If it's the same issue as mine likely is then it'll be a crack or split in one of your vacuum hoses, you'll have to do what was recommended to me and visually inspect all of the hoses for wear/damage, probably starting with the ends of each section where they meet other components.

Use fingertips to feel as well as looking, the splits often seem to form on the underside where they are hard to see. Possibly hotter there.

 

But...if your idling gets better/fixed by lifting the accelerator pedal, I'd've thought it must be a fault with that, and probably nothing else?

 

Don't suppose yours does the same @BrumTom_?

Just now, Wino said:

Don't suppose yours does the same @BrumTom_?

I haven't tried liftting up the throttle pedal, if I experience the rough idle again I shall try it and report back. I'm currently waiting to hear back from a skoda dealer and cloverdale parts re the brake servo vacuum hose.

TPS just said they only deal with trade and couldn't help me.

Cloverdale will comethrough with the win in the end if I had to guess at this stage.

all this time i thought it was the pedal as when i do that pedal pulling then its fixed, i just had what the mechanic told me stick in my head so i thought just keep doing that pedal pull for now.

 

yeah as wino have mentioned, try the pedal pull @BrumTom_

2 minutes ago, BrumTom_ said:

I haven't tried liftting up the throttle pedal, if I experience the rough idle again I shall try it and report back. I'm currently waiting to hear back from a skoda dealer and cloverdale parts re the brake servo vacuum hose.

TPS just said they only deal with trade and couldn't help me.

Cloverdale will comethrough with the win in the end if I had to guess at this stage.

 

Yeah lots of TPS outlets seem to have got stricter recently. They theoretically always were trade only, but some/many used to 'find a way' to serve Joe Public. Fewer seem to do so now including my nearest, when called on the phone anyway.

 

Do examine the pipe though if you haven't already, it might be that someone just taped it up because they'd read (on here for example) that they are a weak point and decided to try preventive medicine? Or trying to fix the same fault but without actually finding splits but just taping anyway.  Always seems to be the joints either side of the one-way valve in my experience, so you won't need to unwrap much to look.

I will definitely inspect the pipe tomorrow. 

 

With the accelerator pedal I've just done an embarrassingly short journey to the shops and back so engine didn't get particularly warm and so I didn't experience the rough idle but the throttle didn't move when I tried to pull it towards me.

Maybe that's more likely the route of your problem @froggy8 as @Winosaid? 

3 minutes ago, BrumTom_ said:

I will definitely inspect the pipe tomorrow. 

 

With the accelerator pedal I've just done an embarrassingly short journey to the shops and back so engine didn't get particularly warm and so I didn't experience the rough idle but the throttle didn't move when I tried to pull it towards me.

Maybe that's more likely the route of your problem @froggy8 as @Winosaid? 

my problem starts like yours when it is warm or driving awhile, i notice as soon as the engine is warm and i go to press clutch down then the needle gets to below 1k then goes further down then back up till i pull the pedal up then its fixed.

 

what did you mean the throttle didnt move?

Just now, froggy8 said:

what did you mean the throttle didnt move?

When in neutral not depressing the accelerator pedal, I put my foot behind it and tried to pull towards me as you suggested, it did not move further towards me 

3 minutes ago, BrumTom_ said:

When in neutral not depressing the accelerator pedal, I put my foot behind it and tried to pull towards me as you suggested, it did not move further towards me 

mine doesnt move too, its hard to explain it really.

3 minutes ago, BrumTom_ said:

When in neutral not depressing the accelerator pedal, I put my foot behind it and tried to pull towards me as you suggested, it did not move further towards me 

it just seem to fix it when i pull the pedal towards me even though it doesnt move.

Edited 15 March, 20215 yr by froggy8

Right ok, so although it doesn't actually move, it fixes something?

 

I'm lost, this far outside of my knowledge 

try it when your rough idle starts again, as mentioned by wino, it might just be your gas pedal and not a leak.

Edited 15 March, 20215 yr by froggy8

1 minute ago, BrumTom_ said:

Right ok, so although it doesn't actually move, it fixes something?

 

I'm lost, this far outside of my knowledge 

yes that is correct, i know its confusing as the pedal doesnt actually move towards you.

1 hour ago, Wino said:

 

Yeah lots of TPS outlets seem to have got stricter recently. They theoretically always were trade only, but some/many used to 'find a way' to serve Joe Public. Fewer seem to do so now including my nearest, when called on the phone anyway.

 

 

My invoices have changed from "Generic Trade Account" to "Generic TAXI TPS generic account"

 

They want to do business but they cant be doing with people who dont know exactly what they want, you cant go in presently and are put through to someone working from home, they are all on commission and if you cant quote what you want and give them your account number they will want to get you off the phone to answer a call from a garage that is next on the on hold queue.

 

I ordered my clutch master cylinder on a Saturday morning, got put through to a guy working from home who called me "mate" and said "I remember you, last time you were buying drive shaft bolts and locktabs", very impressive but I knew actually he had just typed my name into his system and brought up the details, just like any good sales organisation thats the way they build rapport with the customer.

 

Order taken and paid by credit card and I picked up 5 minutes later as they were soon to close and there were no more deliveries that day.

 

So they have sub accounts for the non trade customers that they accept but they are invoiced under the generic one, at least thats what my branch does.

2 minutes ago, J.R. said:

if you cant quote what you want and give them your account number

Well I'm good at the former but how do I get past the latter?

Sometimes they say "cant find you on the system what name is it under?" and I say that you usually invoice me under your generic trade counter sales account, now I will say "Hello its J.R. Generic Taxi from XYZville here!"

 

I even once returned a load of oil that I had bought on promo and filters as I had changed vehicle and it was the wrong grade, different filter etc, I bought as much and more again of the correct grade + filters and didn't argue with the handling charge, they were fine about it.

I'm useless at 'blagging it'. 

Pretty sure I always will be. 

Update, that hose is absolutely split to buggery, there seems to be about 3 layers of electrical tape spanning the entire length of it.

I checked both sides of the non return valve and they both had massive splits at the back, could actually feel one them through the tape now I knew what I was looking for.

It has been taped back up and a replacement hose has been ordered from Mike at cloverdale.

Thank you to both @Wino and @sepulchrave for your help with this.

Hopefully this is the only hose of mine that is split and the vacuum leak is no more.

With a bit of luck you'll kill two birds with one stone; lose the unstable idle, and gain brake booster performance. 

I bet there's a vast number of VW group cars running around with this issue. 

You may be mildly surprised to find your brand new genuine replacement appears to have zero changes to the design or materials.

 

Hopefully so, when it's been swapped I'll take all the tape off and see what the full extent of the splits are, will post a picture if folk are interested.

Here's one I found a couple or three years back; a neighbour's 2005 Polo:

 

 

@Wino I unfortunately think this is worse than your example.

 

The end that goes into the inlet manifold

 

Eitherside of the valve

 

The end going into the brake booster was not cracked somehow.

Checked the date of manufacture and it's 2007, so this has been with the car for it's whole life.

 

New hose is installed and hopefully the car is now happier as a result.

 

Cheers again all for your help.

Edited 19 March, 20215 yr by BrumTom_

1 minute ago, BrumTom_ said:

@Wino I unfortunately think this is worse than your example.

 

The end that goes into the inlet manifold

 

Eitherside of the valve

 

The end going into the brake booster was not cracked somehow.

Checked the date of manufacture and it's 2007, so this has been with the car for it's whole life.

 

New hose is installed and hopefully the car is now happier as a result.

 

Cheers again all for your help.

hi

 

dont mean to be cheeky but you got part number for that hose pipe please? that pipe has split on you and wino so in case mine has split then at least i have the part number to hand.

Have you checked your hose yet?

Part number is: 6Q2 612 041 AL.

I'd recomend getting it from mike at cloverdale car parts, that's where I got it from