2001 Vectra SRI 150 2.2: Power Loss

Matt

Could one of the lambda sensors be on it's way out?
Do a search on the forum for P0420, there are loads of threads with this fault code in them.

150_sri

When the pre-CAT was removed, it was complete.

It would not have been able to physically damage the main CAT as it was stuck at the bottom of downpipe where it bends. There is a flexi pipe in between there and the main CAT.

It seems too coincidental though, car was running perfect before pre-CAT was removed, it was removed and now the engine management light has come on and car is starting to splutter when stationary.

Lambda sensors have been replaced before and also they look fine now.

vocky

it's common for the lambdas to fail soon after removing the precat due to debris from the precat or using wd40 on the threads - this will kill a lambda :thumbdown:

si_c1978

im with vocky,
if the precat had fallen debris from it would have been super heated, then stuck to the cat which would then more than likely eaten away at it. :thumbdown: hence the possibility that the cat operation lambda is kicking up a fuss

MikeS

just cos it is showing a rear lambda fault does not mean the front is playing up either

i have noticed in the past that the rear lambda is operating normally but the front is lazy and static until it has been warmed up enough then when left at idle again after a few minutes it starts to fall asleep - this throws out a p0420 code

symptoms include like an electrical misfire at low revs, lumpy idle and severe power loss

as the pre cat has fallen down the downpipe then i would drop out the front lambda as it is most likely bent

150_sri

Hi Guys,

Thanks for all of the advice.

No WD40 was used to remove lambda sensors they just came out and were not bent, they looked exactly as they should.

The pre-cat was also un-damaged and complete. There does not appear to be any of it missing so not sure how it managed to fall down the downpipe.

Occaisionally as i say the car will misfire when idle, say when i pull up at traffic lights after driving, however performance is not affected, just sounds a bit lumpy with revs fluctuating. The other day the engine management light came on and produced error PO420, this code was cleared and light is now off.

I have driven the car for about 100 miles now and light has not come back on. So im thinking surely there cannot be an issue with the lambda sensors as it would have put the light on by now. Car seemed to go lumpy when the weather was hot however has been fine since, therefore i think the car needs the pre-cat putting back in the exhaust?

Can you buy pre-cats individually or do you need to buy completely new CAT?

Cheers,

SriSte

No they are not available separately. And the chances are, a new cat wont have a precat in. as people keep saying, their not needed, and do not effect emissions.
Your problem lies elsewhere.

jaywanley

the pre cat doesnt affect the engine in anyway shape or form as long as its smooth then it improves the flow this would not make it limpy however if small bits of metal have gotten into the cat from the pre cat tis will as it will melt away at the cat internals and thus damage your cat. id check cat first take it off and see if any signs of damage. If so replce the cat i replaced mine for under £90 from cats direct

sdnatlst

Hi guys, would my vectra C 2.2 z22se 53 plate have this precat in the exhaust downpipe?

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