Power loss 172

[dannyb]

My 172 feels like it's down on power, I thought it was just me but the missus has noticed it too. It's still quick but it does not seem to have the torque it had or as much kick at 5k.

It was recently MOT'd and my tester said it took a while to get the emissions right and that he thinks the cat is on the way out also the car smells rich on startup or when you have turned it off i was thinking maybe the cat that's the problem?

The only other thing to mention is if you have been on a long drive at least 45mins an hour it does really seem to perk up and feel more responsive with maybe a slightly different exhaust note but i can't find a leak.

Any ideas appreciated

 

[CuppyDean]

Most likely the cat its on its way out, basically it will be collasping inside which is restricting the exhaust gases

 

[Christopher]

Might be a dodgy oxygen sensor mate, rather than the cat itself.

If that's misreading then the ECU compensates for something that not there, so you get poor running issues.

 

[Christopher]

Most likely the cat its on its way out, basically it will be collasping inside which is restricting the exhaust gases

Unlikely.

 

[dannyb]

I thought cat collapsing but would prefer 02 sensor , MPG is crap on it too barely over 30 mpg driving it really steady the old phase 2 did loads better. If it was putting too much fuel in would that cause a noticeable power loss?

 

[CuppyDean]

Unlikely.

Why is that?

 

[CuppyDean]

I thought cat collapsing but would prefer 02 sensor , MPG is crap on it too barely over 30 mpg driving it really steady the old phase 2 did loads better. If it was putting too much fuel in would that cause a noticeable power loss?

Ive had a cat collaspe on my previous car and i had similiar problems to what your having now, in the end it completely collasped and restricted the performance alot

 

[dannyb]

Just to add the exhaust does sound different (not as nice) as it did cat back Scorpion

 

[welshname]

Ive had a cat collaspe on my previous car and i had similiar problems to what your having now, in the end it completely collasped and restricted the performance alot

did the collapsed cat get stuck in the cambelt? that really would reduce performance

 

[bennno2005]

Why is that?

If it was collapsing it wouldn't be running very well at all, he'd be struggling to get it past 4 -5k.

Yep the overfuelling would contribute to power loss.

A CAT wont normally fail on its own either, its most likely been "burnt out" if your car has been overfuelling for some time.

 

[bennno2005]

Just to add the exhaust does sound different (not as nice) as it did cat back Scorpion

Is it blowing? As this could cause it fail MOT on emissions

 

[Andyman]

Sounds like its new Lambda sensor time

 

[CuppyDean]

If it was collapsing it wouldn't be running very well at all, he'd be struggling to get it past 4 -5k.

Yep the overfuelling would contribute to power loss.

A CAT wont normally fail on its own either, its most likely been "burnt out" if your car has been overfuelling for some time.

Mine did properly fail it totally collasped inside, only covered 20k miles to when it happened, was a vauxhall though so what did i expect

 

[dannyb]

Is it blowing? As this could cause it fail MOT on emissions

It does sound like it's blowing when you go under a bridge etc but i can't find a leak, However it does smell like its running rich so i suppose i better try a new sensor first as you say if the cat is burnt out it will need a sensor anyway. It's a PH1 so i think it's just the one sensor? I will ahve to price one up cat came back at £100

 

[Dankata]

Don't replace the cat, de-cat

 

[dannyb]

Did think of that but the de-cat pipe is dearer than the cat and apparently a b**ch to fit

 

[Dan519]

It will need a Lambda sensor, and most likely a manifold to downpipe gasket (full kit inc springs and bolts)

 

[nickjchelm]

Hi mate.

Did you ever work out what the problem was? If so what was it and how did you fix it?

I am in a very similar position and any help would be gratefully received.

Cheers

Nick

 

[Nicki Minaj ya Claat]

A bad lambda sensor wont cause problems above 5000RPM at WOT....

Lambda is only used to calculate at idle and some part throttle. It goes into 'closed loop' whenever the throttle is pressed hard. Hopefully he got it sorted. Nickjchelm get yours on a diagnostic as soon as you can.

Fault codes bring up most problems