hi guys

 

had some issues with my car starting.

 

been looking at ruling out a few things

 

took of my throttle body to clean it

 

i noticed it gets stuck in closed position...so will clean it out

 

but i tried to test it off the car by plugging it into car connector  turn ignition on nothing happens

 

started car , and revved it...looked at the flap and nothing...i thought it would be moving when i rev it but nothing

 

does that mean the throttle is faulty?....is there a fuse related to this i can check?

 

 

 

Petrol or diesel?

 

What engine type?

 

Sorry, I see now its in the title, not visible when i was replying.

 

The throttle valve should be closed when the engine is shut down to stop running on, it should be fully open when running except when recirculating the exhaust gases (EGR) if you can see it then you have the intake trunking off & hence there is no airflow through the MAF sensor and the valve will probably not be commanded to open.

Edited 14 March, 20215 yr by J.R.

Diesels don't require the air throttling to run like a petrol does. As J.R has stated above, the 'throttle' valve is for a controlled shutdown of the engine and to create a negative pressure on the EGR pipe from the manifold to promote flow.

 

The flap will bring up a code if its not happy so more than likely not your issue. If it was sticking shut you wouldn't be able to drive the car at all, even if you did manage to start it

Edited 14 March, 20215 yr by SuperbTWM

Its possible the OP may be confused between open and shut, I didn't want to complicate matters with that but as you say the engine would not run with the throttle valve shut.

 

They really should have given it a different name than throttle.

thanks guys just quick update

 

so removed the throttle aka anti shudder valve from front

i noticed that if i pushed it closed i.e so no air gets through) it was sometimes springing back open and other times would get stuck 

 

so i cleaned it with egr cleaner scraping away all bits and even the edges of the spingle.

 

i also cleaned the little valve the metal pipe attaches to

 

i plugged it back into the car without bolting it up, started the car and saw that when i went to turn car off....it closed and then returned to open position so was working

 

put it all back together, car started off its own power(no easy start needed), took it for a 4/5 miles dual carriageway run and it ran fine, accelerated fine, no hesitation and didnt clonk out...last time it clonked out on me within 500 yards so looks to be solved.  my dpf light came on, but i suspected that was due to me trying to start it all those time on the drive with easy start . and i also sprayed some egr cleaner through the air inlet  so some gunk must have come loose.  The dpf light was off next time i started the car.

 

from what i have read, this throttle /anti shudder valve not only closes to shut of the engine but also regulated air pressure some how

 

i will update if issue returns

 

 one thing i have noticed though is that before...i used to turn my ignition on...and i could hear a churping sound from engine as if though something was turning on for a few seconds (like systems waking up) i no longer get that sound? any ideas what that sound relates to?

 

i used the following video for guidance although i havent done the preventative fix yet where he turns the valve other way around 

  

is the rotation of the valve 180 as in this video a good idea  

 

https://www.youtube.com/watch?v=PZojKRL3IoY

Edited 16 March, 20215 yr by bimma123

" .i used to turn my ignition on...and i could hear a churping sound from engine as if though something was turning on for a few seconds (like systems waking up) i no longer get that sound? any ideas what that sound relates to? "

 

When the throttle valve gets stuck closed, the electric motor that drives it still tries to turn.

 

It drives through plastic gears that turn the valve plate.

 

When the valve plate was stuck it will make the gears slip against one another wearing the teeth & making that chirping noise.

 

Now that the valve plate can turn freely, no more noise.

 

The plastic gears will be worn & may eventually fail.

 

It is worth rotating the EGR discharge tube180 degrees to help stop further carbon build-up on the valve.

 

Did you look up into the inlet manifold when you had the valve off, it will be full of carbon & probably restricted about 50%.

I decrunged my throttle valve last year, one of the jobs for when its warmer and I am motivated is to look down the inlet manifold to the ports and valves with an endoscope.

9 hours ago, bimma123 said:

i used the following video for guidance although i havent done the preventative fix yet where he turns the valve other way around 

  

is the rotation of the valve 180 as in this video a good idea 

This change was introduced in the wake of the EA189 update to reduce the buildup of soot and gunk in the throttle body. By turning the fitting around 180* the EGR is introduced in the same direction as the airflow and carried away from the throttle instead of being sent towards it and then turned around by the airflow. When I did mine about a year and a half ago there was very little muck in there. Others have seen huge piles of it. No harm to do it if you have the skills and time to tackle it.

 

On 14/03/2021 at 18:32, J.R. said:

They really should have given it a different name than throttle.

Weellllll, technically it is still a throttle in the strictest sense of the word, it's just throttling the airflow for a different reason than in a petrol engine But yeah, given that most car people think of it as being a petrol only thing it gets a little confusing. I remember doing a double take the first time the concept was introduced in fluid mechanics lectures during my undergrad.

4 minutes ago, chimaera said:

This change was introduced in the wake of the EA189 update to reduce the buildup of soot and gunk in the throttle body. By turning the fitting around 180* the EGR is introduced in the same direction as the airflow and carried away from the throttle instead of being sent towards it and then turned around by the airflow. When I did mine about a year and a half ago there was very little muck in there. Others have seen huge piles of it. No harm to do it if you have the skills and time to tackle it.

 

Weellllll, technically it is still a throttle in the strictest sense of the word, it's just throttling the airflow for a different reason than in a petrol engine But yeah, given that most car people think of it as being a petrol only thing it gets a little confusing. I remember doing a double take the first time the concept was introduced in fluid mechanics lectures during my undergrad.

 

More correctly known as the ASV - Anti-shudder valve.  

2 hours ago, chimaera said:

T

 

Weellllll, technically it is still a throttle in the strictest sense of the word, it's just throttling the airflow for a different reason than in a petrol engine

 

So does a choke!

 

An EGR choke or strangler would be a better term.

8 hours ago, Schtum said:

 

More correctly known as the ASV - Anti-shudder valve.  

Only on earlier engine variants where that was its only function, to help shut the engine off cleanly. 

 

6 hours ago, J.R. said:

So does a choke!

 

An EGR choke or strangler would be a better term.

 

The throttle bodies in both petrol and diesels are often referred to as "controller lid" within ETKA parts lists. e.g. item 2 here exhaust gas recirculation - Superb(SUP) [EUROPA 2012 year] (7zap.com)

Always seems like a dodgy translation from the German.

The best result of my decrunging the EGR butterfly valve aside from the dramatic increase in flexibility and fuel economy was the removal of anxiety that the uncontrolled shut down had been causing me, it felt and sounded exactly like a failing DMF.

 

And like many anxieties I never realise just how much they were affecting me until they are taken away.

 

I bet many owners have been stiffed for a new clutch & DMF only to find that the clonking & shaking on shut down continues.

thanks for the input guys. i will be rotating the valve 180 on the weekend, just wanted to make sure it was ok to do it as its first ive heard of it. Quite easy to do, just remove the metal pipe, and two bolts to undo it . remove and use a grinder to make that little notch on the opposite side so it sits flush. and put it back together.

 

i have ordered a replacement used throttle off ebay and will clean that up and fit it  see if theres any difference in the noise etc  i will also buy a bottle of egr/dpf cleaning fuel additive and stick it in the tank and take on a motorway run to clear things up.

 

I did try to remove the back cover off the throttle body housing to look at the gears but once i removed the torx screws it was sealed on so didnt want to break it. 

 

now that iv got a replacement i will take it off and have a look if theres any damage

 

as for the carbon build up, i didnt look but the hole where the little valve goes in was quite gunked up . but its expected as i olny do approx 7k miles a year and probably been on the motorway 6/7 times in 4 years of ownership...i know its not ideal but its just i dont really have a need to go on the motorway.

 

car started again fine this morning. i was planning on driving it to work but as i reversed off the drive, it had a very little sputter and was ok again but i lost my nerve and left it in case i broke down on the way.  so maybe as one of you said the teeth could be worn on that motor

Edited 18 March, 20215 yr by bimma123

replaced throttle body with a used item from ebay matching part number was only £18 on a discount offer so cheap, i cleaned up and fitted it

 

rotated the valve 180 degrees and re fitted

 

started fine off its own power and took it for a drive, car running  fine so far 

 

will try and open the casing off the old throttle body and see if i can see anything obvious inside

Edited 20 March, 20215 yr by bimma123