Author Topic: Stumbling with initial acceleration. Throttle body issues (I think) (Read 3159 times)

Chew22 · « **on:** 21 May 2016, 08:11 »

Hi guys,

My car jolts when I press the accelerator, for example when I've been coasting slightly downhill in gear, then go to lightly accelerate.

It's a 03 TDI 150.

I decided to start by taking a look at the throttle body

It seems to be super dirty in there, and the pipe leading into it is quite oily too. The blade when pushed gets stuck against the build up.

I have cleaned it out the best I can without removing it from the car and it doesn't get stuck 99% of the time. After taking it for a 20 min test drive, the stumbling appears to have reduced somewhere, so I think I'm looking in the right place.

I really want to remove it so that I can clean it properly, but it looks like an absolute nightmare with incredibly awkward to reach Alan keys. I've watched a few YouTube videos of people removing them on other Mk4 TDI models, bit it seems it's a lot more awkward on the 150. Does anyknow know the best way to do this?
Is there anything else I should be looking at too?

I also have black smoke under acceleration, but I think that is the injectors.

(attempting to upload photos now)

lemski · « **Reply #1 on:** 21 May 2016, 09:06 »

Black smokes normal. If you drive the car hard itll smoke less as it keeps it clear.

Extension pieces is the best way I found but isnt the egr connected to it aswell?

Chew22 · « **Reply #2 on:** 21 May 2016, 09:16 »

Quote from: lemski on 21 May 2016, 09:06

Black smokes normal. If you drive the car hard itll smoke less as it keeps it clear.

Extension pieces is the best way I found but isnt the egr connected to it aswell?

I think I can hunt down a nice collection of extension pieces. It looks like the throttle body and EGR are all one piece?

lemski · « **Reply #3 on:** 21 May 2016, 09:19 »

Yeh so youll have to undo the egr pipe. Which from memory is a bit fiddly. I think if you indo the throttle body, then you have a little better access.to get the two bolts holding the egr.
Theres a chance now to put a blanking plate instead of a gasket.so the egr doesnt do owt, will keep the throttle body alot cleaner

Chew22 · « **Reply #4 on:** 21 May 2016, 12:47 »

So I managed to remove the throttle body and the EGR and give it a proper clean. (see photos)
I'm going to make some blanking plates this afternoon. Also it seems 100X easier to get the bolts back in without putting the EGR pipe back on!

It was no surprise that my manifold was in horrendous state too. Is it worth taking this out and cleaning it? There are massive clumps on build up in there. (hard to photo with an iPhone)