Technical Insulation came out of tailpipe - any rush to replace backbox?

[cambyses]

My 2004 UK Punto 1.2 8v was running intermittently badly (judder at idle, jerky acceleration, poor economy, occasional check engine light). Garage established that lambda reading was very high, but couldn't reproduce the problem for long enough to trace the cause. A few weeks later, it spat a load of material (a bit like a woollen scarf) out of the tailpipe, since when it seems to run fine!

From googling I gather this is sound insulation from the backbox, but there's no noticeable increase in noise. Questions are: is this really the entire problem, i.e. was the blockage caused by the material fooling the lambda sensor? And is there any reason/rush to replace the backbox, or can I run it as is, at least until MOT time?

 

[AndyRKett]

Chances are it will happen again, the inside of the exhaust silencer has rotten and is now falling apart, so could very easily block up again.

It's fairly easy as a diy job if you are so inclined, paying to be done expect it to cost arround £100 but very dependent on where you go and the quality of the parts fitted

[ame]http://youtu.be/pkctWU6s5ag[/ame]

 

[portland_bill]

The internal pipe has rotten and allowed the sound absorbing material to first block the pipe, then be ejected. There is likely to be more to escape, so might just push out, or block the pipe again. The exhaust pulses, like two steps forward, one back. I have known occasions where the insulation can be drawn forward rather than out, and will block the pipe and suffocate the engine. More difficult to clean out if not just the tailbox affected, so sooner rather than later is recommended.

 

[Ziggy122]

been an 8v, it should have a middle pipe and back box

So you may get away with JUST a rear box
Wadding out = Failing inside vs outside
i'd replace sooner vs later personally


Ziggy

 

[cambyses]

Thanks guys - that's really helpful info! I'm loathe to spend unless strictly necessary because it has developed several niggles at once (e.g. see my other thread on the sunroof, and it also put its power steering light on a few months back, although fingers crossed that was a one-off). I don't want to drip money into it if runs for now and might be uneconomical to repair in the near future. So if the main risk is breaking down rather than causing any serious damage, I'll try soldiering on with it as is for a bit longer….

 

[portland_bill]

Carry a couple of wire coat hangars, straightened out and joined together, with a small hook on one end. This might work well as a fishing rod if it becomes blocked.
(Remember to take your litter home!)