Exhaust problems

[ntel]

I've just got the chim back following a service and have been told by the dealer that he is 99% sure that the exhaust system is blocked due to the quietness of the exhaust note and the lack of power (BTW its a 450).

He says either one or both of the pre cats could have disintegrated and blocked the main cat or there could be something wrong inside the silencer.

A couple of weeks ago, whilst driving near Delph, I hit a hidden dip in the road at about 40 MPH and the car grounded twice in quick succession. I heard the exhaust hit the road. I checked under the car for any damage but only found a few scratches on the exhaust.

The car sounded at lot quieter after that and thinking about it now it did loose some pulling power.

Do you guys have any ideas where the problem might lie?

[2 sheds]

Are you sure it was quieter after the grounding, because i would have thought it would be nearly impossible to damage the exhaust enough to restrict flow, Melted cats is more likely.
Tim

[maca]

yeah, they like sleeping under cars during cold weather. if they got caught up under there then your exhaust would certainly melt them...the resultant sticky mess would definitely make the car sound muffled.

[ntel]

2 sheds said:

Are you sure it was quieter after the grounding, because i would have thought it would be nearly impossible to damage the exhaust enough to restrict flow, Melted cats is more likely. Tim

Yes Tim, both the wife and I commented how quiet it sounded afterwards. The exhaust isn't flattened in anyway. Could it be possible that the internal tubes in the silencer could have been dislodged and the wadding has moved thereby blocking the flow of gasses?

If the pre cats have disintegrated, I assume I could clear the debis out of the Y piece and take out what is left in the manifolds. Would the ECU then require re-mapping?

[2 sheds]

It may be possible to break the inside of the silencer, but i haven't come across this before and you have twin 2" pipes, even if one was blocked it would still produce a fare bit of power, i'm not discounting this though seeing as the symptoms occured after the impact.
If you just remove the preCats no re-map required.
Tim

[ntel]

Thanks for the advice Tim. I may have access to an endoscope ( If thats how its spelt ). I'll stick it up the exhaust and have a look inside the silencer. If all is OK then it must be the pre cats as you say.