boost at 0.4

[robo]

Hello
Yesterday I went to see angus's green rs2 ( what a nice example) and runs lovely too well done M8.
After that meeting I got very inspired and got on to cleaning my engine, three hours later looking good, I have started the engine to see if is ok on wet it did run Ok but I did not drive it till today, what a unpleasant surprise I have lost the boost or turbo, would not boost any higher then 0.4 bar with no kick.
Please can any one help?
Thinks I have done
1. Checked for water in air filter
2. I disconnected battery to reset ecu
General check for water
Thanx.

[Doug_RS2]

Sounds like you have disconnected the WGFV - check the coinnections are dry!

[hiltron]

I had same problem when I washed my engine. Water gets down to the plugs. You need to open up and blow out with high pressure. Then you must leave open to air dry. I also had to take plugs out to clean electrodes on misfiring!!! cylinders. Spray all connections from HT coils with good electric spray. I dont have a boost guage, but my car sort of pulled up to 5000rpm thereafter no real pull. Just went like a normal car.
I also opened up all electric connectors and sprayed with electric moisture repellent spray. Hope you get it sorted. I washed my engine twice and it happened to me twice. Ran fine after engine washed, symptoms only came up next day. Dont wash my engine no more.

[robo]

What is wgfv?? is it waste gate f valve??

[Greg_S]

waste gate frequency valve. also known as the N75 valve.

if you look down by your drivers side headlight there should be a small solenoid with 3 pipes on it. one into inlet boot, one to WG one to turbo's cold side
make sure the electrical conn on that is good.

Greg

[robo]

I have solved one problem with water in spark plugs stopped engine misfiring but boost still at 0.4 bar, i've done all electrical connections but boost still at 0.4 bar, done n75 , followed davids advise to find it clicking, tomorrow going to check waste gate spring??????????
Thanx all for your help.

[AAH!]

It may be that the WGFV (aka: N75 or wastegate bypass regulater) is faulty and the car has gone into limp mode. I beleive VAG-COM can confirm this.

The same thing happened to mine recently, maybe the WGFV's are coming to the end of there natural lives.

You could try swapping your WGFV with a known good one. Mine?

I may be wrong and I'm sure i will be corrected if I am, but I seem to remember reading something about disconecting the electrical connector to the WGFV and seeing if the boost improves, which may suggest a faulty WGFV.

With mine Dialynx (my garage of choice) chose to resolve this issue by uprating the standard wastegate spring from the standard 0.4 bar spring to an adjustable 1.5bar spring, removing all the hoses from the WGFV and joining the coldside turbo hose directly to the wastegate hose and sealing the remaining hose. The wastegate is then controlled directly by the cold side boost pressure. The new spring was then adjusted to give about 1.7 bar. The WGFV is left connected to the ECU, which makes it think all is well...sort of, but don't ask me how. I believe if there is a problem with excess boost the ECU causes the car to missfire.

Dialynx originally uprated the turbo to a kkk 26/27 turbo, amoungst other things and remapped the ECU to give a constant 1.5 boost which is still applicable to the recent uprated spring and bypassing of the WGFV. Dialynx said that this is how they often did their "race" prepped 20v engines as it tended to be relaible and becuase the WGFV can be tempramental at times.

I think I have discribed what has been done correctly and so far it all seems to be working very well.

Having said that I have found quite a few threads on various audi forums suggesting that the wgfv should not be played with.


Check out this post on the audiworld forum which explains the role of the WGFV.

http://forums.audiworld.com/s4/msgs/1046677.phtml


Angus

[Greg_S]

Angus,

IMHO just using a stiffer wastegate spring is a very bad way of tuning the car, in effect your taking several steps back in the technology that has been put into the ECU and control systems.

with a properly remapped car with the WGFV connected & a slightly stiffer WG spring it is possible to map the car within safer limits and run more boost on parts of the map to get the tuning right.

If i were you I would get a proper remap done by someone like Mihnea. One of the main reasons for keeping the WGFV is that you still have the limp home mode capability if all goes wrong.

Greg

[robo]

Hello
No luck at all with the car I have tried wgfv from my s2 is identical but still nothing also had no faults on reading , I will try ring Dialynx on Monday maybe they will be able to see the car.
Thanks for the advice.

[AAH!]

Greg

I think your comments are on the whole are fair and you may well be right on this matter and I look forward to a "Mihnea session" and to hear his views. I have followed Mihnea's comments with great interest over the past year or so on various forums and I will continue to look out for your posts as per your proposal of a possible rolling road and remap meet in Bedfordshire with Mihnea, hopefully in mid September - hint, hint.

In the meantime, not being an expert on such things, I have to go with somebodys advice and Kieth at Dialynx does have a good reputation and does know his stuff and has looked after me well over the years.

At the end of the day it seems that there are many ways to get where you are trying to go with different ways of getting there and different experiences along the way. Hopefully I am nearing the end of my journey. (I'm not holding my breath)

all the best.......Angus