in prep for my remap I thought I'd have a good check over the car - using carista (ELM327) nothing comes back so I assumed all good - I also used torque pro to have a look at some live data and something seemed off  on absolute throttle position % with the ignition on it shows 92.5% (pressing the pedal did nothing) engine on goes down  to 88.2% now pressing the pedal seems to make the % go down ...?  I assumed it would read 0-100% starting at 0

 

the car, as far as I'm aware, drives fine (slightly sluggish 1000-1400 RPM) boost seems to hold steady as 22.3 PSI when accelerator fully depressed all through the rev range and drops off as soon as the pedal is released.

 

thinking the TPS is goosed but I can't seem to find any info on replacing it or a replacement part.

 

any help or info on this will be greatly appreciated as i'm sat scratching my head,

Edited 15 June, 20205 yr by Gissin

There is some post on here about resetting the accelerator pedal position by depressing acc fully then turning on ignition and holding it for 30 seconds and then releasing.  Not sure of exact sequence but I’m sure you can find it. I’m on my phone so searching is not so good. 

23 minutes ago, Golf-Fiend said:

There is some post on here about resetting the accelerator pedal position by depressing acc fully then turning on ignition and holding it for 30 seconds and then releasing.  Not sure of exact sequence but I’m sure you can find it. I’m on my phone so searching is not so good. 

yeah I spotted that - gave it a go but nothing changed unfortunately

 

thanks though

is there a separate senor or is it built into the pedal?

 

assuming the throttle sensor is inside and linked to the pedal and not somewhere like the throttle body in the engine. .

There are both, sensors in pedal and throttle body.

thanks, do you know if these can be replaced just sensor only ?

 

http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA) - I was reading this which stated Tdi's donot have throttle bodies ?

11 minutes ago, Wino said:

There are both, sensors in pedal and throttle body.

http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

Modern diesels do have throttle bodies, but they're not used for the same purpose as on petrol engines; so there will be a very different relationship between throttle pedal position and throttle plate than there would on a petrol car (which isn't 1:1 anyway). Must admit, I didn't notice we were talking about a diesel when I posted.

so I can find a Oem throttle body replacement 185VG0510  for £180 - would this be a straight swap not requiring any VCDS witchery

Hold up!

I don't think you've in any way established that there's any fault here!

 

Surely there's a issue if it's reading 80/90% at idle ..and the readings are all over the place like it'll go 32-80-25-62..etc.

 

I'm going to screen record some live data and post it on here later - I'm also going to check the voltage with a multi meter.

after that I'm going to have my local garage run a scan on it see if they can spot anything

I guess after that maybe remove it and check to see if it's all clogged up

then ,maybe think about replacing it.

I don’t have VCDS but a mate of mine does. I vaguely recall when we were tinkering with my car and running scans the Throttle Position values were not a linear 0-100% either.  He said it wasn’t an issue and I had no running problems apart from a failing injector. 
 

Perhaps someone on here could run a scan on their car for these values as a comparison? 

47 minutes ago, Gissin said:

Surely there's a issue if it's reading 80/90% at idle

 

If there was a significant fault, you'd have a code for it, and probably a warning light on?  It's not clear to me whether the readings you're seeing are coming from the pedal sensors, or the TB sensing. Either way, don't go on assumptions, hope that someone rises to the challenge suggested above by @Golf-Fiend and measures what goes on in another similar vehicle.

 

I think you're jumping to conclusions with insufficient info.  Tends to be expensive.

The throttle body has nothing to do with the throttle pedal on the diesel. 
 

the throttle pedal. Has two sensors in it. One goes upscale and one down to cross reference each other. 

1 hour ago, Gissin said:

Surely there's a issue if it's reading 80/90% at idle ..and the readings are all over the place like it'll go 32-80-25-62..etc.

 

 

That will be a dusty/dirty potentiometer, or if by some surprise they are using hall sensors, the magnetic bar has come loose/been damaged. Pots can probably be temporarily fixed with contact cleaner and a good wiggle (once the unit is out of the car and you can see them) could be a loose wire somewhere otherwise causing irractic voltages.

so I looked at the live data again as it just states throttle % so Ive found out exactly what it's monitoring and it's throttle position (manifold) % 

will this make a difference to what the data means 

No. The movement of the throttle body is the EGR working.