# Possible V6 Cold Start Hesitation Fix



## Russ 182 (Jan 31, 2009)

Hi guys,

Now i know there have been quite a few posts made in the past relating to the v6 suffering with hesitation when cold. Usually just for a minute or two and the car is back to normal. I myself have been suffering with this pretty much since i got the car last August.

I tried all the usual suggestions to remedy the problem with no success. (Replace coilpacks, Spark plugs, MAF sensor, Coolant sensor and a throttle body reset).

Here is a video of roughly what i was experiencing -






This resulted in the car occasionally kangaroo'ing when reversing of my drive as well as being really slow to get going from a standstill such as pulling out of a junction. Eventually the problem continued to get worse to the point where even once up to temperature the car would still be really slow off the line and feel like i was riding the clutch as i tried to get going. (Cue me panicking thinking the DSG/mechatronic was on its way out). I performed a Vagcom scan and there were NO fault codes logged which made diagnoses an impossible task until i stumbled upon this fix whilst filling the washer bottle.

If you look at your engine, on the bottom left corner you will see a white ball joint which clips onto a shaft which pops out from the engine manifold.



















Now if you push down on this white ball joint as shown in the video below it should move freely and not stick. Now in my case the shaft that stuck out from the engine (change over barrel) became so stiff that it would not turn at all which resulted in the white ball joint popping itself off every time the solenoid tried to operate the change over barrel.

Now for those that aren't aware. What this setup does is operate the variable intake manifold. The variable intake manifold simply opens and closes a valve depending on engine rpm which dictates whether the engine uses the "performance port" or the "torque port".

The vacuum motor as shown on the above diagram operates a change over barrel in the manifold under the following conditions -

•	At engine speeds below 900 rpm the performance port is open for idling. The performance port valve is actuated.

•	At engine speeds between 900 rpm and 4100 rpm the performance port is closed and the engine produces its maximum low end torque (the performance port valve is not actuated).

•	At engine speeds above 4100 rpm the performance port is open (the performance port valve is actuated).










In short the manifold design gives low down grunt to get moving in the first place and high end power for when your pressing on. Without this operating correctly your either going to have very little low down torque (which is what i was suffering with) or no high end power. Although i think its more likely to be no low down torque you'll suffer with as this is the position the changeover barrel rests in when the engine is off.

*Video-*



So if your the white ball on yours rotates freely my guess is this may not be the fix for you (although it may be worth trying anyway). If however you find that there was some resistance which freed up after you rotated the joint a few times then this may well do the job.

Now im purely speculating here, but my theory is that when the changeover barrel hasn't been operated for some time e.g. overnight it seizes up slightly. This results in the vacuum motor which rotates the white ball joint not being able rotate the changeover barrel which controls the variable intake manifold. The changeover barrel eventually frees up as the vacuum motor keeps trying to operate which then results in the car running as it should.

Eventually mine became so seised that the white ball joint popped off every time the vacuum motor tried to operate the change over barrel. No matter how hard i tried to rotate the change over barrel by hand it wouldn't budge yet under normal circumstances it should rotate freely.

*Right now enough chat and onto the fix which has worked for me -*

Ideally it would be best to do this when the engine is stone cold e.g. car been left over night as this when most people (including myself) seem to suffer with the hesitation.

You will first need to pull the white ball joint of the shaft that operates the changeover barrel as i did in the video. It simply just pulls off with a bit of force.

Now if you look on the side which bolts onto the engine you will see 2 x black torx screws (t25 if i remember correctly) or in my case one torx screw and one pozi screw as i lost one in the engine bay. oops.










Undo the 2 screws as shown above and pull the vacuum motor away from the engine. It should just pop off with a little bit of wiggling around.

Now remember which position the shaft is in before you go any further. Once you've taken note of its position. You simply need rotate the shaft round, backwards and forwards. Under normal operating conditions when the vacuum motor is controlling the change over barrel the shaft will only be rotated 30 degree's or so. What i did was rotate the shaft 180 degrees one way, and 180 degrees the other until it rotated smoothly and freely. With mine being seised solid i personally had to use pliers at first to free the change over barrel up.

Once everything is turning freely reassemble the in the opposite order you removed and go for a test drive. Post back with your results and lets see if we've found a fix to the V6 cold start hesitation issues.

If anyone has anything to add or contribute to this guide please feel free to say and i will happily edit. Apologies for all the science involved in a guide which essentially boils down to undoing two screws and turning a knob backwards and forwards. I just wanted to try and explain what it was that has been causing the hesitation that i've been suffering with and how exactly it has caused these symptoms.

Doing this has worked wonders for me. My TT has never run better it truly is running like a dream now. Having said that with new coil packs, plugs, and MAF it has every reason to be.

This may not be the fix for you, although hopefully it will. Worst case scenario...you've wasted 30 minutes reading this and a further 30 minutes playing with the change over barrel.

Post up your findings guys, let me know if this did or didn't work for you.

Thanks,

Russ


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## CamV6 (Oct 26, 2003)

That is good work and a fantastic write up. I'm gonna save this thread for future reference.


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## peter-ss (Sep 3, 2008)

Excellent write up.

I've requested that it be added to the Knowledge Base.


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## kitcar98 (Nov 8, 2012)

very cool mine was completly stuck so with abit of force it started to swivle and move. havent started the car yet so i will write back when i have.


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## kitcar98 (Nov 8, 2012)

just wondering what happened if you pushed it down and swivled it when the engine was running would it rev the engine or do something bad and all go wrong?
seems silly but just curious to what will happen and dont want to try it myself


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## V6RUL (May 28, 2009)

Be careful as you don't want any broken bits to get lost inside.
It's jammed for a reason and care should be taken to fix it properly..
Steve


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## RazMan (Aug 28, 2012)

You could try a little silicone spray lube to help ease it, working it into the bearing surface as you free it up.


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## bassett (Mar 17, 2013)

Bringing back an old thread but a great little guide and seems to have added a bit of punch to my V6's mid range. Wasnt quite the easy install i expected as i dropped a thick red rubber cylinder off of the shaft and guess where it landed - at the very bottom of the engine bay, DOH!!! So a note to people attempting this push a plastic bag in below the vacuum unit to catch small parts just incase this happens to you as i wasted an extra hour jacking the car up and removing the undertray just to retrieve this little rubber piece. 
Adam


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## alan123 (Aug 3, 2012)

How can I check the vacum motor is working. :? Decided to check this out and I found that the change over barrel shaft worked freely on mine  , but when I started the car from cold this didnt appear to open even when I manually rotated it fell back to the closed position.  
So Im guessing I need to first check the operation of this at over 4100 revs so will have to wait till Ive been out in the car and its nice and warm. 
I can feel a small diameter pipe from the bottom of the vacum pump, is this the vacum hose that should operate the pump? Any advice would be great.


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## SiW (Apr 20, 2017)

Thread from the dead warning.

My V6 hesitates at low revs - don't know if this is just the DSG or the engine. When on power it's fine.

Does the above assume it's just the bearing at fault rather than the actuator itself?

If so, would a spray of WD40 be advised and then wiggle it around?

Have done plugs and packs on mine but not the MAF etc.

If the above is not the source of the hesitation what else could it be?

Cheers,

Simon


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## MCIP (Aug 16, 2014)

Dont know if anyone can help but just checked mine whilst someone slowly revved the engine from tick over and up to 4k revs but nothing moved, Should it have operated whilst just revving it or does it only operated whilst driving (under load) :?


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## rusTTy_racer (Sep 7, 2015)

You need to give a very quick hard dab of the throttle pedal to get this to work at a standstill. Not impossible but tricky


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## MCIP (Aug 16, 2014)

Thanks rusTTy-racer, ill give it a go later, Mart.


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## thaidaz (Jun 21, 2017)

Thanks a lot for your guide Russ, I have just replaced mine which has been broken from a "mechanic friend". I tried to glue it but it lasted a few weeks only:
https://ibb.co/jmVQUy


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## thaidaz (Jun 21, 2017)

MCIP said:


> Dont know if anyone can help but just checked mine whilst someone slowly revved the engine from tick over and up to 4k revs but nothing moved, Should it have operated whilst just revving it or does it only operated whilst driving (under load) :?


Hi MCIP, I have just replaced mine, check how it works, I believe it should be like this. This was in the garage after the installation:

https://drive.google.com/open?id=17yhdkOCpiO-b8txSkdqhzQwyfkNxM5Ck


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