CAT Gone? RAC called..

[Mark51]

Driving to work tonight my car was VERY under powered. I could not get it over 2k in any gear. Revved freely when out of gear but not as free as it normally does.
When in gear its very very under powered and judders like its going to stall.
Managed to get to a layby and called the RAC. THe guy wasn't much help but did suggest it was the CAT. However, there was no eggy smell which i thought that there would be if the cat was fcuked.?!?!
There was also no diagnositc code on his mahcine either. The only thing i have done is clean the throttle pedal connector with some electrical spray cleaner but can't see it been that was its not been running right the past couple of days.

Any help guys?

 

[Mark51]

anyone?

 

[karl b]

similar happened to me mate and I found out it was the Lamda sensor in the cat...

 

[Mark51]

surely this would throw a fault code up though?
I was thinking of taking the cat off and driving it to see if it was any better but not sure how this would perform without the lambda sensors in.?

 

[sophiesdad]

surely this would throw a fault code up though?
I was thinking of taking the cat off and driving it to see if it was any better but not sure how this would perform without the lambda sensors in.?

yes give that a go ,
does it run rough just idling ?

 

[karl b]

I would try that mate and see how it goes...!

 

[Mark51]

yes give that a go ,
does it run rough just idling ?

Slightly lumpy but they all do this. It does rev freely but feels and sounds restricted in some way.
Just need to figure out how to get the cat off now. Anyone?

 

[sophiesdad]

the joint is above where the rear part of the subframe sits , bit awkward.

 

[Mark51]

any thoughts on it been the ECU?

 

[Fred@BTM]

it'll be an electronic fault more than likley

is it running on all 4?

any lights on the dash?

 

[KMB]

Also, check your alloys are not getting hot, sounds silly but it could be a badly sticking brake caliper.

 

[Mark51]

it'll be an electronic fault more than likley

is it running on all 4?

any lights on the dash?

no lights on the dash atall apart from the normal ones.

How would i check this? Its not misfiring on idle

 

[Fred@BTM]

does it sound like a subaru?

 

[Mark51]

lol, only slightly but then it starts to judder so have not wanted to push it anymore with fear of breaking a mount

 

[Fred@BTM]

get the plugs out and check the tips, sounds like you have a misfire

 

[Mark51]

Would this not misfire on idle?
So you don;t think its the cat?
Thanks for your help Fred

 

[Fred@BTM]

i've never seen a failed cat on a 172, so no LOL

 

[Mark51]

hmmmmmm, the plod thickens, unfortunately.

Will get the plugs out this afternoon then and see if the are sooted up. Guessing this would show me if they were fooked.

If its not them Fred where do you suggest i check next?

 

[Fred@BTM]

you need to check the tips on the plugs

 

[Mark51]

you need to check the tips on the plugs

for?

sorry

 

[Fred@BTM]

to see if its burnt away, will be obvious when you have all 4 out next to each other

 

[Mark51]

OK cheers Fred

 

[Mark51]

Changed the plug and they were black. However, it has made no difference at all.

Any further ideas anyone?

 

[Fred@BTM]

leads or coilpack

without seeing the car the forum can only help so much

 

[Mark51]

i know, cheers fred. Just taken the 1st lambda sensor out and it doesnt run any free-er just alot louder

 

[Mark51]

think im going to take the plung and get it into the garage

 

[bearne1]

Coilpack is the most obvious answer, fairly cheap part to buy and return if it doesn't fix the problem

 

[Mark51]

i wouldn't have thought that it would start if it was the coli pack tbh or if it did start i would have thought it would stall pretty quick

 

[Da]

Any videos?

Does it sound like this -

Ignoring the fact it's a Yozza exhaust.

 

[Mark51]

at work atm and have no speakers. Its sounds like i have a big Max Power cone air filter on when i rev it. Will have a look this afternoon at that vid when i get in from work DA

 

[Da]

Ok, well by the description of your symptoms I would guess at the MAP sensor.

Have a look here - page 7.

 

[kingsalderman]

had a megane had a similer problem , the cat had fell to bits inside and was restricting the exhaust gas .

 

[scotty2hotty81]

as fred said cats are a rare failure.
lambda sensors dont always throw up a fault code.
i would go with leads or coil pack as they could be breaking down under load, so would start fine and run until you want to drive it.

 

[Mark51]

Ok, well by the description of your symptoms I would guess at the MAP sensor.

Have a look here - page 7.

Yeah that does sound similar. Ive seen a MAP sensor on ebay for £23.50 delivered. Still again i would have thought that the MAP sensor would have come up on the diagnostic machine

as fred said cats are a rare failure.
lambda sensors dont always throw up a fault code.
i would go with leads or coil pack as they could be breaking down under load, so would start fine and run until you want to drive it.

So how would this explain the plugs been sooted up?

 

[Da]

MAP didn't show anything on the diag with mine, which is why it took so long to diagnose.

 

[Mark51]

hmmmm, in two minds what to do now then.
Plugs £12
Map sensor £23.50
Coil Pack and HT leads £35
CAT £140

I also had trouble with a map that i loaded on from an RS Tuner and Henk thought that there was a problem with the throttle around 4k. Not sure if these problems are related or not.

 

[Hutchie]

feck paying for a cat, take of join behind and have a look in, i have seen a 172 one melt and turn 90 degree.s blocking the exhaust. knocked it out with a big bar. car runs lovely now

 

[Soot1e]

hmmmm, in two minds what to do now then.
Plugs £12
Map sensor £23.50
Coil Pack and HT leads £35
CAT £140

I also had trouble with a map that i loaded on from an RS Tuner and Henk thought that there was a problem with the throttle around 4k. Not sure if these problems are related or not.

Try the cheapest parts 1st.

 

[Fred@BTM]

hmmmm, in two minds what to do now then.
Plugs £12
Map sensor £23.50
Coil Pack and HT leads £35
CAT £140

I also had trouble with a map that i loaded on from an RS Tuner and Henk thought that there was a problem with the throttle around 4k. Not sure if these problems are related or not.

erm where are you getting your parts?

plugs £40
MAP sensor £90
Coil pack and leads £200
CAT £500

 

[Mark51]

erm where are you getting your parts?

plugs £40
MAP sensor £90
Coil pack and leads £200
CAT £500

plugs - Halfords
Coil pack & leads, Map sensor - ebay with 3 month warrenty
CAT - www.cats2u.co.uk