S5 TII

I don't know when this happened but today I can't seem to get my car up to full boost. When I step on it in any gear, except 1st where I get no positive pressure at all, the stock boost guage pegs about 3 of the bars up (yea yea, get a real boost guage).

I have checked the engine codes and there were none. I remember reading that with the ignition in the 'on' position the boost guage is supposed to go to '0', this doesn't happen. I was concerened that it used to get about half way there before, now it doesn't move at all.

I'm a little new to the whole car problem troubleshooting thing so any help is appreciated.

Thanks.

//Ent

 

get a heyes manual and go through the trobleshooting section that you have just discribed. Ya gotta start learning sometime, why not now? Also I sure you will get some detailed help from a turbo expert.

 

is the power down too?

 

Yea, it doesn't pull quite as hard as it used to.

I have a haynes, bought it the first day I got the car. Problem is, it mostly applies to S4 cars almost every time I read it, there's something that doesn't match my car.

Thanks.

//Ent

 

You are right on on that one. It can be tricky decifering the differences in the "s4 manual" when you have an s5 car.

If it was my car the first thing I would try to do would be to figure out the source of low boost. What I mean by this is: is the turbo not boosting because the cats are clogged adn it cant get the exhaust out fast enough; can't get air in fast enough, as in clogged filter or what not; is the turbo shot; Is it electrical? ECU not wanting to boost... Error codes? (I know you already checked that, just being complete in my answer)

 

I'm waiting on a k&n cone filter, I guess when I get I guess it won't be the air filter. I doubt the cats are clogged, the car only has 70k kms (~45k miles) on it. I'm sure that I don't have a blown turbo, no smoke or excessive oil usage (uses a little less oil than it should be). Could be electrical, I haven't had any other electrical problems except when someone tried to steal the car and blew several fuses (knock on wood, heh).

Seems the best thing to do is wait for the air filter and resurrect this thread if I still have problems as the car runs fine otherwise.

Thanks.

//Ent

 

Hey I have the same problem with my TII also has low boost on 1st then as I get closer to 5th the boost start to get better I'm still trying to find out the problem, if you find out what wrong with your car first post it




Thank You

 

Is it possible that the wastegate is stuck slightly open....?

 

Okay, odd thing happened on the way to work this morning.

Pulsing boost, the turbo would spool up then down and so forth.

So I stayed out of boost the rest of the way (usually run the car pretty hard at 5am), tried to stay off it on the way home and, of course I forget, I push it a little hard.

The car behaved normally, except for the rattle in the exaust that I noticed when I got home. Looks like it may have been the pre-cat getting broken up as that's where the rattle is coming from. I guess I'll gut it this weekend. I'd just buy a downpipe but I'm broke because someone decided to try to steal the car a little while ago and I'm out like $1500.

Oh well, thanks.

//Ent

 

the turbo wont make much boost in first gear cause there no load. i dont know how a s5 works compared to s4 in actual boost regulation but check for vacuum leaks. the wastegate actuator may not be working properly. but it can be many things. check the service manual and properly diagnose it. if its one thing ive learned in school is proper diagnostics. not just trial and error. you figure things out much faster.