old cat

[gray-vtr03]

hi
just had my car on the diagnostic at the garage and he says it's saying the cat is old, is this a genuine reason for the engine light to be on? i couldn't see it on the list of codes posed at the top.

i wouldn't be too bothered but car's running horrible in low gears stuttering like its out of fuel, he say's needs a new cat to clear the fault then go from there but the cat's £100 odd quid i could do with out spending now

[Jigs2895]

If the cat isn't working to its full efficiency and cleaning the exhaust gasses properly then the post cat lamba sensor will throw up an engine management light, however usually the cat rusts and forms holes before the material inside them stops working though.

Wouldn't say that is whats causing your stuttering, when was the last time the fuel filter was changed?

[gray-vtr03]

i thought the fuel filter first and changed it only a couple of weeks ago and did the plugs and air filter at the same time , it was better for awhile but now its crap again, i'm starting to think it's the fuel pump fuel guage is even more unreliable than ever!

[stevo67]

Do you have a list of the codes showing up?

[Mickswan]

It'll be the sensor rather than the cat.

[VTR_Craig]

Cat efficiency low can flag a fault code.

Why not get a second hand one to stick on to be sure before buying a new one

ask the garage if they will put it through an emissions test and keep an eye on the co2 figure

Some cars will still go through a test with a cat efficiency fault code

[gray-vtr03]

No sorry no fault codes I can't read them myself, going off what the garage told me,
This was a second hand cat after my downpipe split!
Would it be this that would cause the bad running at low Rev's tho?

[Manu]

I'd also bet on a dodgy sensor. The thing is, when the car senses a dodgy cat, it will overfuel a little and that may cause the car to run badly because the air/fuel mix is too rich.

Keep in mind that buying an OBD 2 fault reader for a tenner on amazon is a good investment, considering most garages will charge you double or even triple that just to read a fault.

Cat efficiency low can flag a fault code.

Some cars will still go through a test with a cat efficiency fault code

pretty much, the EML flags up at 95% efficiency.

[gray-vtr03]

ok thanks for the replies,
so what do i need to search for on amazon to get the right code reader?

[Manu]

4 quid and 20 pence shipping, can't beat that: http://www.amazon.co.uk/Bluetooth-Diagnostic-Scanner-Engine-READER/dp/B004KL0I9I/ref=sr_1_1?ie=UTF8&qid=1364087383&sr=8-1

[gray-vtr03]

cheers manu, ordered now, see what heppens when it turns up!!
runs really rough still but seams worse when low on fuel like when it gets to about a quarter left, so might be more fuel related than the cat?

[Manu]

^^^ excellent value for money and may be useful in the future too...


I had a similar problem in my car. As it turned out the previous owner put a bit of diesel in there and the car would sometimes let out a puff of smoke when going downhill on a low tank.

It's common on older cars to find deposits in the tank, a new fuel filter generally solves it though the best fix is to flush the tank completely.

[Manu]

Make sure it's gonna work though, I have an OBDII code reader and it won't work on my Saxo because it's a year too old (W reg, manufactured 99, registered 00) it plugs in fine, but won't connect to the ECU.)

Op's profile says 03' VTR so should be fine.

[gray-vtr03]

manu i've already tried new fuel filter, so thinking the tank drain maybe next :(
not looking forward to trying that!