VAGCOM logs - very low boost in low revs

[martziniuk]

My reason for suggesting the turbo bolts was due to a few threads like this one

http://briskoda.net/octavia-i/manifold-exhaust-problem/145597/

and the fact you said it sounds like a hole in the exhaust.

I'm not too sure how the turbo is removed but i would have thought it would be from underneath.

[sabikeuk]

My reason for suggesting the turbo bolts was due to a few threads like this one

http://briskoda.net/octavia-i/manifold-exhaust-problem/145597/

and the fact you said it sounds like a hole in the exhaust.

I'm not too sure how the turbo is removed but i would have thought it would be from underneath.

Where exactly are these 3 turbo to manifold bolts?

[David 8]

Where exactly are these 3 turbo to manifold bolts?

They are where the turbo joins the manifold ..................:rofl:

You need to get under the car too see it really and it's above your steering rack

[sabikeuk]

They are where the turbo joins the manifold ..................:rofl:

You need to get under the car too see it really and it's above your steering rack

On attached photo turbo is on one side, manifold on another ....

[David 8]

On attached photo turbo is on one side, manifold on another ....

Thats just a diagram

The line I've drawn is your engine block

HTH

[martziniuk]

On attached photo turbo is on one side, manifold on another ....

Your thinking of the inlet manifold. The turbo is connected to the exhaust manifold.

[sabikeuk]

Your thinking of the inlet manifold. The turbo is connected to the exhaust manifold.

Still I have no idea how to get there, it is on the back of the engine, no access from the bottom...and I won't remove half of the engine...

[martziniuk]

Just had a look at mine. No it looks like access is from the top and it is at the back of the engine. I can just reach my three bolts but i would need to take the top engine cover off and the stainless steel pipe to check the gaskets. There are three bolts which hold the turbo to the manifold, by the look of it. The TT turbo is a different setup to the Vrs so you maybe best to ask on their forum if this does not sound familiar.

[sabikeuk]

Just had a look at mine. No it looks like access is from the top and it is at the back of the engine. I can just reach my three bolts but i would need to take the top engine cover off and the stainless steel pipe to check the gaskets. There are three bolts which hold the turbo to the manifold, by the look of it. The TT turbo is a different setup to the Vrs so you maybe best to ask on their forum if this does not sound familiar.

Thanks for looking . I Attached photo of TT engine, basically turbo is in the back.

On another photo is 180 engine and it looks to me that turbo is on the left side, on my 225 is on the back. Am I right?

[sabikeuk]

Do you think these 3 bolts which I circled in red?

[martziniuk]

I think they are the ones, they are the ones i was feeling i think.

[sabikeuk]

I think they are the ones, they are the ones i was feeling i think.

I had to remove metal charge pipe to intercooller but I got there, however bolts weren't lossen :( ....

[martziniuk]

Oh boy! well you'll have to keep searching for that noise then. I take it there wasn't any soot around the flange?

[sabikeuk]

Oh boy! well you'll have to keep searching for that noise then. I take it there wasn't any soot around the flange?

I couldn't see any soot, anyway it was really hard to get there and I couldn't see much....wants to DIY boost tester....

[sabikeuk]

I am going to do a leak test this week I hope I will find any leak .

[martziniuk]

Good luck, let us know the results.

[sabikeuk]

I have tried to do a leak test today. I have used electric pump (it says up to 250 psi on it - also tried to put same air into tyre and it works well) however It didn't work - gauge didn't move, stayed at zero all the time, there was pressure in hoses after a while but when I stopped compressor air released in 10 sec from hoses and I could not hear any leak only bubbling (can be oil).

I removed oil cap and clamped oil breather pipe also.

any idea?

[martziniuk]

Yeah i tried mine the other day, i blanked off the pcv valve in the TIP and blew up the pipes with a tank compressor. I went up to 23psi and found no pipe leaks. You need quite a bit of air to do it properly and it did leak into the crankcase a bit but no leaks in the pipe work. I would try a decent compressor for air tools and get the pressure up to 23 psi and see if there are any leaks.

[sabikeuk]

Yeah i tried mine the other day, i blanked off the pcv valve in the TIP and blew up the pipes with a tank compressor. I went up to 23psi and found no pipe leaks. You need quite a bit of air to do it properly and it did leak into the crankcase a bit but no leaks in the pipe work. I would try a decent compressor for air tools and get the pressure up to 23 psi and see if there are any leaks.

I have found (I hope) leak at vacuum hose under manifold (on the photo). Now it will be challenge to change it .

[karlbar2k]

I am a muppet!! didnt read the rest of the page to see the answers already there. DOHH

"not sure about the noises but your logs show a boost leak. the requested at low revs means nothing it is just what the ecu is requesting, as the revs rise the turbo plays catchup and ususally overboosts a little before settling back to the requested. your log shows that you are not getting to the requested at all, like 400Mbar short. I am not sure about the N75 as it could be the way it was mapped to limit it to 87.5% at maximum load? but you need to check your Turbo to Throttle pipework for leaks."

Edited 23 June, 2009 by karlbar2k
Muppet!

[karlbar2k]

I have found (I hope) leak at vacuum hose under manifold (on the photo). Now it will be challenge to change it .

sometimes the vacuum jet pump (the yshaped thing in the photo) can leak as well. fairly cheap from VW but a bitch to change

[sabikeuk]

sometimes the vacuum jet pump (the yshaped thing in the photo) can leak as well. fairly cheap from VW but a bitch to change

Thanks for your reply....do you mean that part on the photo where is green arrow?

Any idea which are "Turbo to Throttle pipework" hoses ?

Dan

[sabikeuk]

The latest update...I have fixed that broken vacuum hose and also found another broken hose (see photo) however I don't feel that it is as it should be. Maybe power increased slightly but it definitely not pushing me down to seat

.

Any idea somebody?

[sabikeuk]

sometimes the vacuum jet pump (the yshaped thing in the photo) can leak as well. fairly cheap from VW but a bitch to change

would be a faulty jet pump a reason of my low boost?

[martziniuk]

I would imagine the vacuum and breather pipes will be minor air losses, yours looks like it's losing quite a bit of pressure.