Boost problems again

[shark_90]

OK I've just got back (and used about £10 fuel in 10 minutes!).

General boost through midrange at WOT is around 1 bar
Boost at redline from 3rd - 4th is lower, say 0.6-0.7 bar
Only time I see boost very high is if I put it in 6th at 1800rpm and give it WOT - then it goes up to around 1.4 bar

Does that sound normal?

The other thing to note is that when I was in 6th at WOT I could obviously hear more of what was going on in the car due to the lower engine speed.. and I could hear a distinct hiss from the back of the car. Bear in mind I have no back seats.. is the hiss likely to be the fuel pump wanging a load of fuel through or is it likely to be a boost leak (in the back?!) or some other boost related thingummy?

[Acidburn]

could be a leak from the pipes that go to the diff.

[shark_90]

Here?

[Acidburn]

Yeah those are the pipes for the diff lock.

[UrS4boy]

Thanks for all the replies, thats given me alot of things to check ...checked and replugged in all the connectors for the coil loom, they are all nice and tight. I then made sure all the coils were seated ok on the plugs, and realised they seemed quite loose.... then it dawned on me; I hadnt cut down the rings on the rubber section They are now visibly seated abit deeper, alot tighter to pull off, and feel like they are making a better connection with the plugs.Fingers crossed, the coils not making a good connection was the problem!

Well at least the coil issue is solved. As per my DIY instructions, I always suggest that you remove the rubber sealing ring from one coil pack and test it on the plug to a) feel/hear the click/snap onto the plug and b) measure the depth from the top of the cam cover to the top of the coil pack so after you have reinstalled the trimmed rubber sealing ring (trimmed as per my photo), you know that you have installed the coil pack correctly.

As for 9 psi, it's too low IMHO. You must have a boost leak or the hose to the MAP sensor is off somewhere and the 9 psi is from the Waste Gate (with a stiffer spring and/or turned down stock spring). Stock max should be something like 16 to 18 psi. MTM Stage 1 levels (with K24) should be around 22 psi.

Check your manifold to ECU boost signal hoses for leaks/weak OE clamps, and check the turbo to throttle body boost hoses (and intercooler) for leaks (via pressure test).

Good Luck.

[shark_90]

Yeah those are the pipes for the diff lock.

Pipes look OK but I guess the pressure has to go somewhere? Perhaps what I can hear is the pressure bleeding off?

[Jas11n]

There's a one way valve there, or should be. It's to stop boost pressure being presented to the rear difflock actuator. Thread below is from a Coupe setup, not sure if the avant differs in this area, but worth checking.
Come to think of it, there should also be another one of these one way valves on the small bore hosing coming from the rear of the inlet manifold before it disappears through the bulkhead. At least there is on mine.

http://www.s2forum.com/forum/showthread.php?t=19941

[shark_90]

Well there's going to be a leak now, seeing as I've just snapped the fecking nozzle off that the black fabric hose connects to. It made a hissing noise as it came off and for about 6-7 seconds afterwards.. what have I gone and done now?

[fendent]

similar problem here

I've got a similar problem. My fuel comsumption is up by at least 50'%. I checked the tubes for holes but there are none. Maybe the clamps. Fault codes are 561 and 539 which is probably caused by emptying the tank to below 10l.
My assumptions:
1. leak in a valve (either pressuer regulating valve near the mass connection points) or the pop off valve.
2. wiring loom. It has more than doubled the life expectancy.
3. dried electrolytic capacitors inside the ECU.
4. a marten was active under the bonnet.
5. a slack joint somewhere

As I work for a wiring manufacturer the second point seems to be the next investment. Automotive wiring is designed to last 3000 hours. With an average speed of 50km/h this makes 150000km life expectancy. If someone wants to know more let me know.
Having the engine overhauled by Lehmann Triesen is not an option because of my wallet, at least at the moment.

Well I might have to come to the next meet & greet in the UK as you have the best knowledge alltogether. Here in Switzerlnad there are not that many ABY's anymore. So who knows them well enough to really help without useless trial & error search for the root cause. This I can do myself if only I would take the time to do it.

Regards
Marcel

[dest]

Would it be possible for people to start their own threads for their different problems? Its abit confusing!!!

Anyway, I was able to give it a good long blast on the way home from work:
Started off low down the revs in 4th and floored it, saw a consistant 11-12psi which held all the way up to the red line, into 5th and carried on 11-12psi but as I got higher up the revs, you could definitly feel it holding back slightly (best way to describe is a slight pulsing feeling)
Into 6th and it was still showing 11-12, but as I started getting higher up the revs I noticed it had tailed off to about 7-8.
Then I ran out of straight lol

So, short blasts of boost and it seems fine, but give it a long stretch of its legs and its holding back abit....

[quattronutter]

probably a small boost/intake leak...

[dest]

Well, it was all going so well....

On the way home gave it some boost, and it was holding back worse than ever, lifted off and gave it boost again, and then instantly started cutting it everytime.
Driving across town to home, it was struggling to idle with it dipping to near enough stalling and then revving to just under 1k to keep running.

Ive had enough now, it will be for sale once ive moved house in 3 weeks.
Its the worst ****ing car Ive ever owned.

[quattronutter]

check maf to turbo pipe,usually splits at the bottom near turbo

[waad_uk]

If you need a usb vagcom lead, I have one you can borrow.....

[Jamo]

Sounds like the knock sensors but did you say you have had them replaced?