Z3M catalyst

[EstorilBlue]

I've just recovered from a double shock... the first being that my year 2000 Z3M (S50-B32 engine) has failed it's MoT emissions but far, far worse, the shock of speaking to BMW and asking about the cost of replacement catalytic converter pipes!

So, not having won last weeks UK lottery, I've just spent a good few hours scouring the internet to see if there are any non-OEM solutions out there. It's fair to say that I've not found anything that could be considered a 'bolt-on' solution. Even companies like Milltek don't do them (not enough Z3M owners out there I guess) and Scorpion don't even speak to telephone callers! Magnaflow appear to sell a 400 cell cat that would require welding in place of the original cats but, their shape is wrong - the originals have an offset pipe location whereas the Magnaflows are central. Also, from what I've read, aftermarket cat's aren't renowned for their longevity.

Used OEM catalytic pipes appear to be as rare as hens teeth and in any case, you can't be sure if they'll even work! I'm presuming that I'm not the only one that's suffered from this problem, anyone have any suggestions or solutions? I'd love to get my Z back on the road before summer ends!

 

[Pingu]

What prices have you been quoted?

 

[EstorilBlue]

£3,900 including the dreaded Vodka And Tonic although that includes a £500 surcharge if the old cat is returned in an un-repaired condition - i.e, no welding.

 

[Pingu]

I'd check the salvage of the old cat. You may be able to get more that £600 for it.

Keep us informed about any other prices as this is going to hit us all.

Have you tried anything to get through the MOT. An Italian tune-up is a good start. £20 of Shell V-Power and an hours fun clipping the limiter.

Where are you based? I'm in NG10 and would be happy to have a look.

 

[Ianmc]

Just checked my invoice for replacement BMW M44 cat in June 2018. £1063.83 plus VAT. Also had to pay 212.76 surcharge as failed cat (not OEM) was not returnable. All up was £1642.49 (including gaskets, nuts and bolts, labour and VAT) from a good indy.
The car has had no emission problems since.
Cat should be a key check when buying, hindsight is wonderful!!

 

[t-tony]

Which gas(s) did it fail on CO2 or HC . Did you get a copy of the test result (the station should give you one) if they didn’t they will be able print a copy from the emission testing equipment. Did they get the engine oil up to temp (80 deg.minimum)? it will say on the printout if they did, or, more likely if it was bypassed. If it was bypassed it was not tested correctly and may have removed the last chance of it passing the emission test. Reading the oil temperature places the emissions machine into a different testing range to allow for older cars. Have you used any chemical treatment such as Cat-a- clean etc.?

Tony.

 

[EstorilBlue]

FYI I've attached the fail certificate. I've known the tester for many years (a fellow petrolhead), he'll go the extra mile to get the car through it's emissions test but this time it wasn't going to go. The car had been stood for about 7 months but I always run the engine up to operating temperature at least once a month. I'd taken it for a really good run on the local lanes the day before the test and I know that the car would have been tested at normal operating temperature. One thing I didn't think about until now is that (other than the small crossover by the cats) it's a dual system. Perhaps testing on the other box might make a difference?

 

[t-tony]

It should be tested on both tail pipes the results added and then divided by 2 if it is 2 separate systems . Regardless how long you have known the man he should still have tested the oil temperature after it failed the initial BET (Basic EmissionTest) to give the car the best chance of passing. It states in bold type that oil temp. was bypassed, WHY? Also the car passed with very low CO readings but failed the Lambda that means the engine is running way too lean so I don’t personally think the cat(s) are at fault. Even the HC content is extremely low (14 parts per million PPM) again says to me the engine is running on fumes.

Tony.

 

[Pingu]

FYI I've attached the fail certificate. I've known the tester for many years (a fellow petrolhead), he'll go the extra mile to get the car through it's emissions test but this time it wasn't going to go. The car had been stood for about 7 months but I always run the engine up to operating temperature at least once a month. I'd taken it for a really good run on the local lanes the day before the test and I know that the car would have been tested at normal operating temperature. One thing I didn't think about until now is that (other than the small crossover by the cats) it's a dual system. Perhaps testing on the other box might make a difference?

That looks to be quite a bad fail. It also looks like you are just up the road. Just bringing the car up to temperature is not enough to keep the internals clean. It needs to be either taken for a good forty-five minute drive (15 warm-up, 15 blast, 15 cool-down), or left alone.

Mine would have failed, but the tester tested again on the other pipes. My car is also an S50B32 and has similar mileage (145,000 miles).

What fuel do you use? Do you try to stick to a single brand, or do you just stick in any high octane?

What engine oil do you use?

Any engine modifications?

 

[Duncodin]

It should be tested on both tail pipes the results added and then divided by 2 if it is 2 separate systems . Regardless how long you have known the man he should still have tested the oil temperature after it failed the initial BET (Basic EmissionTest) to give the car the best chance of passing. It states in bold type that oil temp. was bypassed, WHY? Also the car passed with very low CO readings but failed the Lambda that means the engine is running way too lean so I don’t personally think the cat(s) are at fault. Even the HC content is extremely low (14 parts per million PPM) again says to me the engine is running on fumes.

Tony.

Tony. Given your experience, what do you think is the problem. We don't want him taking out a second mortgage to buy cats when the problem is elsewhere.

 

[t-tony]

Maybe running live data on the O2 sensors might throw some light. The heater circuit(s) possibly not working? They will warm eventually but like a knackered thermostat it takes too long. Would be interesting to do an emission test on a cool engine to compare.

Tony.

 

[Pingu]

Maybe running live data on the O2 sensors might throw some light. The heater circuit(s) possibly not working? They will warm eventually but like a knackered thermostat it takes too long. Would be interesting to do an emission test on a cool engine to compare.

Tony.

I suspect that we already know the cool engine results .

The test was completed at 08:52. Unless the OP took it for a good drive before the test, the cat would have been too cool, and the oil was probably not up to temp, either. The coolant gets to 80°C in about 5-10 minutes at idle. I wouldn't be surprised if the engine never gets to 80°C if the car isn't driven, especially if the bonnet is open.

 

[t-tony]

I've done a cool engine test on a vehicle with the same(ish) readings as this one in the past and it passed the test. Which backed up my theory then that it was running on very lean mixture or getting unmetered air into the motor. Lambda as you will know, but not every one does, is a fancy name for air/fuel ratio and this one is "off the scale".

Tony.

 

[Andyboy]

Those should be similar to an E46 M3. I would be very surprised if they need replacement. I'd try some cat cleaner and a good caning.

 

[EstorilBlue]

That looks to be quite a bad fail. It also looks like you are just up the road. Just bringing the car up to temperature is not enough to keep the internals clean. It needs to be either taken for a good forty-five minute drive (15 warm-up, 15 blast, 15 cool-down), or left alone.

Mine would have failed, but the tester tested again on the other pipes. My car is also an S50B32 and has similar mileage (145,000 miles).

What fuel do you use? Do you try to stick to a single brand, or do you just stick in any high octane?

What engine oil do you use?

Any engine modifications?

As a rule, I usually use Shell V Power as I can get this from a nearby garage. I use Mobil 1 0w40 engine oil, usually changed every 4-5000 miles. The engine is absolutely standard.

 

[Pingu]

As a rule, I usually use Shell V Power as I can get this from a nearby garage. I use Mobil 1 0w40 engine oil, usually changed every 4-5000 miles. The engine is absolutely standard.

That's the perfect recipe for a thoroughbred . That's not your problem.

 

[Lazzzydog]

Do we have a happy ending to this story?

 

[EstorilBlue]

Not yet! I've had to concentrate on the house renovation for the past year or so so the Z3M's had to take a back seat. This summer (!) I finally managed to get enough free time to start working on it. A friend in my village has a car lift so I've just replaced the rear subframe bushes - a royal pain of a job but it's done now. A good clean and waxoyl later and it looks nice and tidy. I'm thinking of taking it for a seriously hard run before taking it for it's test again and see what happens. If it fails again I think it'll be a cat replacement job.

 

[Lazzzydog]

Not yet! I've had to concentrate on the house renovation for the past year or so so the Z3M's had to take a back seat. This summer (!) I finally managed to get enough free time to start working on it. A friend in my village has a car lift so I've just replaced the rear subframe bushes - a royal pain of a job but it's done now. A good clean and waxoyl later and it looks nice and tidy. I'm thinking of taking it for a seriously hard run before taking it for it's test again and see what happens. If it fails again I think it'll be a cat replacement job.

I would tend to take Tony's advice and get the fueling checked before splashing out on cats.

 

[Pingu]

I would tend to take Tony's advice and get the fueling checked before splashing out on cats.

I have the capability to record live data on an S50B32. The tests will tell if the MAF is working and if the O2 sensor is working (S50B32 only has one sensor - S54B32 has two). It will also give you their readings. As I said, you are only in Belper. The offer is there if you want me to have a look, preferably on your mate's ramp.

Your cat should be ok unless it has been damaged by a physical knock or has had the wrong fuel used.

Exhaust leaks (especially pre-cat) also throw up strange readings. So make sure that the exhaust is in perfect condition.

My car passed last week and it had only done 38 miles between MOTs. 35 of those were the Italian tune-up before the MOT.