Help! Rear Muffler affecting power/performance?

[schivers]

Hi,

I'm fresh to this forum as well as to mechanics in general, though I am a generally handy sort of person. My rear muffler is now rusted out completely (the exhaust is now detached from the front entrance to the muffler), and I've noticed the performance/power of the car getting slowly worse (on my 2001 daewoo lanos, 1.5L hatchback). Not only has there been a loss of power, but the power is now a bit jumpy when I accelerate, particularly at low revs. I've taken off the rear muffler, but have noticed that the power issue is still present (there's just less noise now). I read somewhere that the rear muffler can help to balance the power of the engine, to deliver more efficient performance. Though the general trend seems to be that the rear muffler isn't vital to engine power/performance, but is mostly to act as a silencer/muffler of engine noise.

I've now ordered a new rear muffler off ebay, and am planning to replace it myself hoping this will resolve the issue. But if the power issue remains the same with the defective rear muffler removed, am I doing the right thing? I was afraid that leaving the defective muffler on for so long may have caused further problems up the exhaust (middle or front muffler), or even worse with the engine!?

I don't have a permanent job and am really short on cash, which is why I'm taking this DIY approach. Someone please give some advice on whether the rear muffler may be the cause of this jumpy and weakened performance/power state of my lanos.

VERY MUCH APPRECIATED for any replies.

Cheers,

Steve.

[daewooluvr]

sounds like catalytic convertor to me

[schivers]

sounds like catalytic convertor to me

Hope not, I've had that before and remember it being expensive. I remember the cat as being a distinct sort of rattling as well, which I'm not getting with this problem.

Thanks for the suggestion.

[Daniele84]

we have the same problem, mine is a sedan 1.6 16V, I'm going crazy.

[daewooluvr]

sounds like catalytic convertor to me

Hope not, I've had that before and remember it being expensive. I remember the cat as being a distinct sort of rattling as well, which I'm not getting with this problem.

Thanks for the suggestion.

The only rattling you get from the cat is if the spot welds on the shield break. If the cat clogs you'll notice the power problems you're having now.

[schivers]

sounds like catalytic convertor to me

Hope not, I've had that before and remember it being expensive. I remember the cat as being a distinct sort of rattling as well, which I'm not getting with this problem.

Thanks for the suggestion.

The only rattling you get from the cat is if the spot welds on the shield break. If the cat clogs you'll notice the power problems you're having now.

Oh ok. Could the rear muffler cause the cat to clog in any way?

My new rear muffler arrived today, I'll put it on and hope for the best. It got dented during delivery though, dammit!

[schivers]

I've replaced the rear muffler, and the car seems a lot better now, except I am still getting jumpy power. So maybe the CAT is clogged a bit? Is there anyway of unclogging it (nice long drive?), or do I have to get a new one. Daniela, maybe yours is a clogged CAT as well?

I'm wondering if driving around with the dodgy rear muffler on so long (which was rusted all around the welds), has caused the CAT to clog up quicker then usual?

Thanks daewooluvr, it probably would've taken me a while to think of the CAT.

[daewooluvr]

I've replaced the rear muffler, and the car seems a lot better now, except I am still getting jumpy power. So maybe the CAT is clogged a bit? Is there anyway of unclogging it (nice long drive?), or do I have to get a new one. Daniela, maybe yours is a clogged CAT as well?

I'm wondering if driving around with the dodgy rear muffler on so long (which was rusted all around the welds), has caused the CAT to clog up quicker then usual?

Thanks daewooluvr, it probably would've taken me a while to think of the CAT.

no the muffler wouldn't affect the cat.

[tafisama]

My friend had the same problem .His engine would overheat,lose power,cut out and so on.He changed the catalytic convertor and the car bounced back to normal.I have heard stories on the Lanos where the rear muffler is a culprit too.

[schivers]

Anybody else out there with suggestions please for my original post?

[schivers]

My friend had the same problem .His engine would overheat,lose power,cut out and so on.He changed the catalytic convertor and the car bounced back to normal.I have heard stories on the Lanos where the rear muffler is a culprit too.

I don't get the overheating problem, I'm just getting the jumpy power output. I'm still wondering if a long drive might somehow clear things up.