pottsy

Please help me!!
I'm going mad trying to solve this one. Car is a MY00 UK Turbo with 80k on the clock. Standard apart from Prodrive back box and de-cat centre.
The other day I was driving along in 4th gear on part throttle, put my foot down a little and felt like I had no power. I was then not able to get more than 0.5bar boost after that. Was low on fuel at the time so I filled it up and reset the ECU (no codes when I checked).
Was ok for few days and then it did it again. Still no codes. Reset again and ok for a day or so.
Next time I took it out it was making just short of 1bar, but felt like the ignition was being retarded. Shortly afterwards, 0.5bar again. Its also a bit jerky under power.
Over the same period of time the exhaust has started to rattle like mad and I've established that the downpipe heat shield is loose and potentially so is the downpipe.
As you blip the throttle it rattles like mad when listening from below, like the big ends have gone almost, however when I hold the downpipe with a piece of wood, the noise goes.
My theory is that the engine is sensing "knock" due to the downpipe rattling and going into safe mode, or retarding the ignition/boost. What do you lot reckon?

xX Domino Xx

sounds like limp home mode. what fuel are you running it on? when was the last time you changed the plugs?

pottsy

Iridium plugs at last service, about 4k ago.
Tesco 99 fuel

Feels like limp home mode, can't get it to go back to normal even after a reset now either, whereas I could before. Rattle is worse now than ever.

Do the downpipes have a little bracket on them just below the turbo, if so I think it might be broken?

M535I

if the dowpipe has a cat in it has it collapsed ?

pottsy

I wondered if the cat had collapsed but there is definitely movement in the downpipe so I'm wondering if the studs/nuts have come loose or broken at the turbo maybe?
If it is loose then I would have thought the vibration was enough to make the knock sensor get extra noise.

cbr337

also wot about the wastegate flap that might be playin up as it can burn part of them self's away which would give you not much boost as the exhaust gases would escape via that instead of spinning the turbo up to its proper psi

M535I

well if the bolts have snapped you would hear it blowing surley ? just wait till the car is cold and look for the stud's if they are there give the cat a wack see if it rattles if it does take it off smash the middle out bob's your uncleyour back with full power lol , need a new one formot though lol .

pottsy

Thanks for replies, exhaust is deffo loose but not blowing noticeably. Strange.
Ordered new MAF today on the basis that its no bad thing to fit a new one even if its not that, as well as to eliminate it.
Deffo an exhaust issue I reckon. Might take the opportunity to fit a de-cat downpipe although will re-fit the centre cat for MOT's.

pottsy

Now sorted. It was the MAF and the exhaust rattle was a complete red herring.
Dead pleased its solved as I had visions of changing everything before I fixed it.
At least the exhaust rattle gives me an excuse to de-cat