I'm looking for a bit of advice, i know there's been a few topics recently about turbos going pop but mine's seems to be fine (touch wood).

Last night, after about 80 miles of normal driving, 40-65mph, i had cruise control set in 6th gear and when i stepped on the throttle to pull out and overtake nothing happened. I turned cruise off, dropped down a gear and again nothing happened - there was no boost. There was no bang beforehand, no clunking, smells or smoke so i assumed it was a boost leak/split hose and nusred it home at 2k revs in 6th. The temp. gauge stayed vedrtical as it always does and I checked the car when i to my girlfriend's - another 20 miles down the road - but couldn't see anything. By this time it was dark, so i had my dinner then headed to my mum and dad's thinking that the car was going to have no turbo. I started it up, it hadn't really had time to cool down much, drove up the road and the turbo was back. It seems to be fine now too. What could have caused this?

To cover all the bases - the car is an SE (BLT), standard bar a Shark map (which it's had for about a year), the temp. gauge didn't move, it struggled to rev past 2,500 rpm in any gear and there was no issue before it just stopped boosting. The only thing i noticed was a slight hesitation @ 1800-2000rpm, ever so slightly more than what it does usually.

The final thing, which is probably unrelated, but worth mentioning is that when i got out the car this morning after it driving normally, there was a 10 amp fuse lying loose in the driver's footwell. I haven't been near the fuses and it wasn't in there from the previous owner as i've thouroughly cleaned the car out. The fusebox at the side of the dash was untouched, but i have had to lift my throttle pedel to get it to idle, are there any fuses down there i could have knocked out?

Sorry for the long read but i'm clueless so want to cover everything. If someone suggest running the car with the MAF disconnected i'll need a walk-through so be kind!

Cheers

Sounds like the vanes sticking in the turbo to myself but I'm not an expert.

http://www.audi-sport.net/vb/a4-s4-forum-b5-chassis/107121-un-sticking-your-tdi-vnt-turbo-vanes.html

Adam

cheers lads, that guide is spot-on. I'll get onto it this week.

Any idea where the fuse could be from? Seems like a hell of a coincidence but i can't place it - no idea where it could have come from

or our in house guide i did, with pictures.

http://www.briskoda.net/forums/topic/243533-the-mr-muscle-vnt-turbo-treatment-thought-we-needed-a-guide-of-sorts/

Could be same problem I experienced - faulty MAP sensor. causes all boost to be lost. can happen anytime. Also, can come back just by restarting.

I had the exact same thing...faulty MAP sensor.

P.