Can't get full throttle!!

[Rusty]

Been having some problems recently with the engine almost cutting out on anthing over half throttle. It seems to be when the turbo is cutting in. I have to admit that I had run it on 95 fuel when it first started and attributed the problem down to pre-ignition due to the wrong fuel. I have since run it only on Optimax and initially used some fuel additive to boost the octane. This seemed to cure the problem and she was running fine. I've done nearly 500 miles since the problem started with a mix of motorway and cross-country and on full throttle the power delivery seems to fluctuate. However, today she started playing-up again and was worse than ever. She's ok on light throttle with the turbo running at low load but when I increase the throttle she then cuts the power very harshly. Am going out to road test it after leaving it ot rest for a bit so will update this if anything changes. Any suggestions would be grateful.

Cheers

Andy

[martinjs]

Highly likely a boost leak.
does it cut out at 4krpm when you floor it?
it sounds like the overboost protection cutting in, you need to check all your hoses from the turbo through to the throttle body,
+ dumpvalve etc, have you replaced the useless intercooler o-ring with the 'mark h mod hose'?
try doing a search for boost leak, theres loads of topics about it, we've all been there at some point.

HTH
martin

[Rusty]

Cuts out at any revs when you floor it! Thinking it's overboost protection. Will check all hoses as suggested. Fitted a k&n pannel filter and read of one fouling the air flow meter so will clean that in the process.

[pjeast73]

I had exactly same problem for months - truned out my leak was coming form the intercooler itself (tiny holes in it). Fixed these but still had problems cutting out - was sorted with a new MAF. Just a thought

[sps-si]

andy if its not a boost leak or you can't find the fault feel free to pop down and we can put the car on the scanner.

[tamaquatt]

I had similar problems a while back and cured them with a new MAF too!!

[scouser_75]

Same problem here a few months ago - Changed a couple of hoses and problem was gone. Almost defo down to boost leak.

[valjo]

i have the some problems, first i check up for any leaks in hoses system, then i cleaned the maf and problems gone........

[Rusty]

Si, cheers for the offer but I've already had the ECU read... Sounds like a horospcope or something!

Cheers to everyone for your suggestions.

Made some progress.

Took the MAF and inlet hoses, airbox etc off and cleaned the MAF. Also checked some acessible hoses and attempted to reset the ecu by disconnecting the battery for a couple of hours, worked on my old Golf so assumed it was worth a try! Also found excessive wear on the outside of the small hose going from the WG to the inlet so will have to replace that soon. Put everything back together and replaced the K&N with the original paper filter following a read of a thread by an Australian chap who'd had a problem whith his S2 after fitting a K&N and...

...It works fine (fingers crossed).

Took it to All Audi in Bristol and have the ECU read for fault codes which came back clean.

Just to add insult to injury, whilst running rough, the top hose on the radiator popped off in Cheltenham whilst on a shopping trip with a lady and pissed coolant all over the engine bay and, less importantly, the road and a Shell garage (My new Optimax blessed friend!). Steam started pouring from the bonnet and I had brown trousers about the cost of replacing whatever had gone pop! Turns out that the pipe on top of the radiator, which appears almost breand new, had snapped half way down and only a jubilee clip was holding on the hose. Of course with a bit of heat an pressure it popped off. Anyway, getting a new rad tomorrow to solve the problem.

Cheers as always

Andy

[Rusty]

UPDATE:- Car was still playing up so I took off as many hoses as I could find, checked them and refitted them. Not the most fun in the world but when needs must... Seems better but then it always does!

Andy