Hi

Our lad's Felicia has failed its MOT on the CO Fast Idle Test. It seems to be about double the max allowed value. Garage apparently are reluctant to give an estimate to repair.

What is it likely to be? Catalyst? What else could it be and how hard would it be to diagnose?

Just trying to get an estimate to see if it would be better to find another car as it needs some brake pipes and there's a few advisories as well....

I'd start with an Italian tune-up, and see if you can get the test repeated on a known hot engine.

After this, I'd think of new plugs and HT leads (if applicable), and new air filter element. Then move on to the lambda sensor and the cat (well, unless the cat's rattling, in which case it's probably breaking up internally.

As for the advisories, no comment unless I knew what they were, beyond that I've had advisories in yearN, no work done and no advisory in yearN+1.

I'd start with an Italian tune-up, and see if you can get the test repeated on a known hot engine.

After this, I'd think of new plugs and HT leads (if applicable), and new air filter element. Then move on to the lambda sensor and the cat (well, unless the cat's rattling, in which case it's probably breaking up internally.

As for the advisories, no comment unless I knew what they were, beyond that I've had advisories in yearN, no work done and no advisory in yearN+1.

Tyres and wheel bearings + service brakes only just effective enough. Not too worried about those as can estimate cost, its the cat/lambda diagnosis that is unknown. As you say STP and up the motorway first I think.

Well, I've seen an advisory "Tyres - 'only' 6mm tread remaining", and they're wearing parts anyway. How long do you give the car if you get it new brake pipes and tyres, since the brake pipes and new fluid might sort the brake power?

Well, I've seen an advisory "Tyres - 'only' 6mm tread remaining", and they're wearing parts anyway. How long do you give the car if you get it new brake pipes and tyres, since the brake pipes and new fluid might sort the brake power?

TBH its the emissions that is the worry. If we can take that out of the equation I think it probably makes some sense to get the brake pipes fixed. Not really worried about tyres, wheel bearings etc as there's no immediate need and on that basis we can take our time finding bits and bobs.

i would try the lambor sensor and cat is it a 1.3mpi if so i have a spare cat

I've got a cat here too for a 1.3mpi which I was going to chuck in the scrap metal bin, I've probably Got a lambda probe here too which you are welcome to gratis.

Can you post up a list of all the emissions test results to get my old grey matter ticking over on a possible cause/solution.

In particular, the actual voltage on the lambda sensor could be very diagnostic.

I've got a cat here too for a 1.3mpi which I was going to chuck in the scrap metal bin, I've probably Got a lambda probe here too which you are welcome to gratis.

Can you post up a list of all the emissions test results to get my old grey matter ticking over on a possible cause/solution.

Many thanks for the offer (and Uma, but Teflon is closer to home). He's put some injector cleaner in it and he's back off to the garage later today after "warming up" on the motorway. If we're still struggling will be in touch.

The figures were:

Engine Temp 80°C

Fast Idle Test

Engine Speed = 2650rpm

CO = 0.61% (Fail Max 0.30%)

HC = 93 ppm (Pass)

Lambda = 1.011 (Pass)

Fast Idle Test

Engine Speed = 2563rpm

CO = 0.58% (Fail Max 0.30%)

HC = 80 ppm (Pass)

Lambda = 1.008 (Pass)

Natural Idle Test

Engine Speed = 805rpm

CO = 0.48% (Pass Max 0.50%)

The car has had plugs, air filter, oil and oil filter changed about 4K miles ago. I bought a petrol filter at the same time but couldn't work out how to change it and so it didn't happen.

Again any help much appreciated.

could be a cheap fix afterall with the kind offers here

could be a cheap fix afterall with the kind offers here

Engine Temp 80°C

Fast Idle Test

Engine Speed = 2650rpm

CO = 0.61% (Fail Max 0.30%)

HC = 93 ppm (Pass)

Lambda = 1.011 (Pass)

Fast Idle Test

Engine Speed = 2563rpm

CO = 0.58% (Fail Max 0.30%)

HC = 80 ppm (Pass)

Lambda = 1.008 (Pass)

Natural Idle Test

Engine Speed = 805rpm

CO = 0.48% (Pass Max 0.50%)

With those figures it's a safe bet that the lambda probe is working properly beuase if it weren't working the lambda reading would be lower that that and the HC would be much higher, further more I'd say that the engine must be in fairly good health with a HC reading like that too so I wouldn't bother wasting money changing the plugs or much else tbh because the engine is obviously burning quite cleanly, a high CO reading like yours is almost certainly a failed catalytic convertor.. Driving it up at warp speed to get it red hot probably won't make any difference to the CO reading at all if I'm being honest.

With those figures it's a safe bet that the lambda probe is working properly beuase if it weren't working the lambda reading would be lower that that and the HC would be much higher, further more I'd say that the engine must be in fairly good health with a HC reading like that too so I wouldn't bother wasting money changing the plugs or much else tbh because the engine is obviously burning quite cleanly, a high CO reading like yours is almost certainly a failed catalytic convertor.. Driving it up at warp speed to get it red hot probably won't make any difference to the CO reading at all if I'm being honest.

Thanks...its still reading .60 CO so I'll PM you about the cat if that's OK.

Yeah, I'd say cat as well looking at those numbers. Should be cheap and easy enough for a secondhand one.

Cat did the trick, MOTed for another year yesterday. Thanks to all for comments and especially TeflonTom for his help and advice.

Next job: rear wheel bearings I think!

Ah ha

I was wondering if you'd got it sorted yet

rear wheel bearings are fairly tricky to change, you need a special tool to drive the new bearing races into the brake drum, the outer one is 60mm and the inner one is 40mm, what I did with mine is make up a pair of tools on my lathe which I can use to press the bearing races in which have a hole in the centre of each one so I can use a long piece of threaded bar and 2 nuts to wind them both in at the same time..

I, however, made my tools up using Pikey methods. Bashed the original wheelbearings out, and then ran the grinder round the outside to reduce the OD just enough to let them go in and out without any resistance. Then you can drive the new bearings into place without issue. Takes about 15 minutes a side in total, start to finish, once you have the tools.

Tom's solution is better, though.