Black soot coming out of exhaust

Rachel!!!! said:
An update after getting the code reader on it. No fault codes were stored that have anything to do with the issue (there were a couple of others)
We got some readings which mean nothing to me so no idea if normal or not. I will list them below so any help would be much appreciated.

Before cat reading of 2.0, after the cat 0.7
Oxygen sensor readings at idle - additional mixture 1: 0.2 Additional mixture 2: 0.55
At 2500 rpm 0.06 and 0.11
With the MAF disconnected readings were the same
Multiplicative mixture 1: -3.63 Mixture 2: -0.42

Cylinders true running value at idle
1: between -10 and -20
2: +25 to +35
3: -30 to -50
4: +15 to +30
5: +70 to +80
6: -70 to -90
Click to expand...
Was good to meet you Rachel. Unfortunately my expertise only runs to reading out what the code reader screen says.
Hopefully someone can give us more info?

Just to add that Rachel's car is returning around 31mpg, mostly on short commutes.
It runs beautifully, no rattles, no hunting, no signs of air leaks.
In fact no indication that anything is wrong except for lots of small splashes over the bumper and boot, above the exhaust. These are almost watery looking and grey in colour, not thick and black as I'd expect if it were oil.
With the engine idling I put my hand across the exhaust for about 30 seconds and it came away dry. So maybe something that happens at higher revs? Or only after a long time of running? Or maybe the 40 minutes run to my place was enough to clear it out?

Interested to hear everyone's thoughts?
 
Did a lot of water get squirted into the exhaust pipe when washing it at some point ?
 
I've learnt over the last thirty odd years that one of the delights of Norfolk and Suffolk is no motorways or good 'A' roads but plodding around the lanes or sitting in traffic brings other problems.

I finally got rid of recurring O2 sensor codes by taking the Zed over to visit my Mam in Manchester via the Snake - and I 'drove it like I stole it' all the way there and back mostly in fourth and fifth with a heavy right foot. Great advice from the forum - never enjoyed doing a job so much!

If its not throwing codes and all the outwards signs are that the engine is healthy then 'use' it and clear all the sh1t from the system. Can't remember if its a daily from your posts but if its doing the commute and just getting warm (not really hot) then in the cool weather everything condenses as it cools and any soot (un-burnt fuel) gets washed out next time it starts. If its an auto (did you say?) in traffic its not going to rev hard and generate any heat where some of us might drive a manual a little harder in town.
 
Crazy Harry said:
I've learnt over the last thirty odd years that one of the delights of Norfolk and Suffolk is no motorways or good 'A' roads but plodding around the lanes or sitting in traffic brings other problems.

I finally got rid of recurring O2 sensor codes by taking the Zed over to visit my Mam in Manchester via the Snake - and I 'drove it like I stole it' all the way there and back mostly in fourth and fifth with a heavy right foot. Great advice from the forum - never enjoyed doing a job so much!

If its not throwing codes and all the outwards signs are that the engine is healthy then 'use' it and clear all the sh1t from the system. Can't remember if its a daily from your posts but if its doing the commute and just getting warm (not really hot) then in the cool weather everything condenses as it cools and any soot (un-burnt fuel) gets washed out next time it starts. If its an auto (did you say?) in traffic its not going to rev hard and generate any heat where some of us might drive a manual a little harder in town.
Click to expand...

Sound advice that.
[ref]Rachel!!!![/ref], we did discuss that last night while you were here. So hopefully you opened it up a bit on the way home?
Even if you did have the roof up :poke: :D (Ha, bet you thought you got away with that?)

Another option, though not quite as good, is to keep it one gear lower than normal on your commute, so it's revving a bit more.........

But overall, unless [ref]colb[/ref] can throw any light on the readings we got, then a regular thrash should hopefully clear it all out.
 
Just to answer some of the questions asked it's a manual and it's used as my daily. I've never squirted water into the exhaust, I wash it with a hose not pressure washer and make sure it doesn't go up there.
I will take all the above advice and make sure it gets some longer runs, which it will anyway now lockdown travel restrictions have lifted and drive it like it's meant to be driven! and hope that helps.

Thanks again enough_zed for your help, it's been reassuring to know that someone with a bit of knowledge doesn't think it's anything too serious and yes I did give it a good drive both on the way to yours and the way home. I also took it the long route home from work today to avoid getting stuck in traffic lights at ongoing roadworks so will stick with that for a bit and hope it helps.
 
In the absence of any fuel related codes it looks like the sensors are ok and you have no air leaks, The figures you posted look in range if they were not it would have set codes. Must admit I would chgeck out the actual performance of the exhaust sensors by viewing them in live data in a graph format using my engine check software. If the precat sensors are working correctly they will produce a ranging up and down voltage that displays as a nice uniform wave form in the graph, if they do that then they are ok. Post Cat sensors often look pretty static with minimum movement in the graph display, they would react if they detect rich or lean exhaust after its passed through the Cat. If they are duff then again I would expect a code to be set. In live data you can also view how much air is being passed through ther Maf, if it increases with throttle opening it at least shows its working, disconnecting its electrical connection mearly puts the car into default settings, if it runs better disconnected then that could be an indication that its duff. As you had no change when you disconnected I would assume yours is ok. I would tend to agree with what has been said earlier about short runs and low temp as probably being the main cause of sooty exhaust, a longer run and some spirited driving may well clear it out and improve things.
If there was something wrong I would expect the EML to come on after it tries to compensate for any misfueling issues casused by air leaks, just keep an eye out for the EML just in case.
 
A failing ccv system can cause sooty tailpipes as the engine is breathing in oily fumes, usually causes higher than normal oil consumption to go with it.
Rob
 
Smartbear said:
A failing ccv system can cause sooty tailpipes as the engine is breathing in oily fumes, usually causes higher than normal oil consumption to go with it.
Rob
Click to expand...

Definately not using oil, I had to top up with 1 litre in November and it's only 1 mark down from full on the digital dash display so barely used any.

Thanks for the advice colb, I will see how it goes with some longer, harder drives. I'm considering buying a code reader myself if need be.
 
Rachel!!!! said:
Smartbear said:
A failing ccv system can cause sooty tailpipes as the engine is breathing in oily fumes, usually causes higher than normal oil consumption to go with it.
Rob
Click to expand...

Definately not using oil, I had to top up with 1 litre in November and it's only 1 mark down from full on the digital dash display so barely used any.

Thanks for the advice colb, I will see how it goes with some longer, harder drives. I'm considering buying a code reader myself if need be.
Click to expand...

Sounds like it's ok then [ref]Rachel!!!![/ref]. Keep an eye on it just in case, but I think the better weather and opportunity to give it longer runs will be beneficial.
Regarding the code reader: whilst the one I have is pretty good and has a wide range of functions, it does not show the graphical live data as Colb described. Not sure if any do tbh?
I'm sure [ref]colb[/ref] can advise but I suspect you'd need one of the fancier programmes on a laptop and matching input cables?

For now, the money may be better spent on a tank of fuel and a few decent runs.
Can always use mine for other stuff until you get your own.
 
As to Code Readers and Diagnostics a lot of people seem to be using Creator 310 code readers these days that do quite a few functions including airbag resets.
For more detailed diagnostics a Laptop based system is probably the way to go with all the software and emulators being available via ebay for little outlay. Its worth bearing in mind some of the software are very large files and can take up a lot of room on your laptop, often better to find an old working laptop and take that into use purley for diagnostics use.Anything from Windows XP up to Windows 10 will do for an operating system for the software to work via a USB port.
BMW INPA diagnostics available via ebay from BCCables is the supplier of software and emulator with cable. You may need a 16pin to 20pin cable changer if you want to plug into older models like Z3 who have diagnostic socket in the engine compartment. Z4 is ok via the 16pin OBD2 in the drivers footwell for connection.
I also use BMW Scanner 1.4 which is again obtained from ebay, this is so simple to use and includes some limited coding capabilities. Far more easier to use and understand than the INPA software.
I do like another system I have called Engine Check Pro which comes from a company called Gendan Automotive based in Swansea https://www.gendan.co.uk/
I do like the ability to view live data from sensors in graph form, makes it much easier than having to scan loads of numerical lists. Been using this for yearsw and once you have bought it you get lifetime support should you need to download it again, I have had a laptop die and it was simple to get the download again once they had checked the original purchase.
A really cheap way into Diagnostics is to get an ELM327 emulator either in WiFi or Blutooth from ebay then download an App called Torque on your phone, this will provide you with code reading and clearing except airbags will also display live data from sensors and you can build a custom dashboard to view whatever sensors readings you want. Drawback is screen size but quite a capable portable bit of kit to have.
Just starting out on diagnostics I would point you to the Creator 310 as a start, that should do what you want for modest outlay, going to save the price of the unit the first time you use it as opposed to lining a garages pocket just for code reading.
 
colb said:
Just starting out on diagnostics I would point you to the Creator 310 as a start, that should do what you want for modest outlay, going to save the price of the unit the first time you use it as opposed to lining a garages pocket just for code reading.
Click to expand...

A comprehensive read, thank you.
I have the Autophix 5900 which seems very capable as a code reader, plus battery reg, e-brake wind back for pad changes, some live data reading etc. It has certainly saved me a lot of time and expense by isolating exactly which component has the issue. Cannot comment on the Creator 310 but from reading on the forum it seems to be more or less the same in performance as the 5900?
 
Thanks for that. The laptop based diagnostics seems well out of my capabilities and price range when I won't use them to their full capacity but I'm keeping an eye on the price of the Autophix 5900 as it seemed very easy to use and I'll also have a look at the Creator 310.
 
My 2007 2.5si on 74K miles is the same if it's been idling. I have it on good authority (Mike at Zed Shed), that it's a result of shrinkage of the valve stem seals and they let a bit of oil through. Nothing to be overly concerned about, it will just use a bit of oil. It can be fixed as anything can but it's a big job as the head has to come off. I'm fairly confident it will not register as a fault.
 
Daz W said:
My 2007 2.5si on 74K miles is the same if it's been idling. I have it on good authority (Mike at Zed Shed), that it's a result of shrinkage of the valve stem seals and they let a bit of oil through. Nothing to be overly concerned about, it will just use a bit of oil. It can be fixed as anything can but it's a big job as the head has to come off. I'm fairly confident it will not register as a fault.
Click to expand...

I've only just seen your comment but thank you, I really appreciate your input. That's definately put my mind at rest.
 
Rachel!!!! said:
Daz W said:
My 2007 2.5si on 74K miles is the same if it's been idling. I have it on good authority (Mike at Zed Shed), that it's a result of shrinkage of the valve stem seals and they let a bit of oil through. Nothing to be overly concerned about, it will just use a bit of oil. It can be fixed as anything can but it's a big job as the head has to come off. I'm fairly confident it will not register as a fault.
Click to expand...

I've only just seen your comment but thank you, I really appreciate your input. That's definately put my mind at rest.
Click to expand...
Have you managed to give it any longer runs to see if it clears up?
 
Yeah I've been driving it on longer runs but it hasn't made a difference. I think it does it more when I put my foot down as I've been cleaning it after each trip to try and work out when it's happening more.
 
Rachel!!!! said:
Yeah I've been driving it on longer runs but it hasn't made a difference. I think it does it more when I put my foot down as I've been cleaning it after each trip to try and work out when it's happening more.
Click to expand...
Hmmm, that's interesting. almost as though higher revs are causing oil to be drawn in?
Definitely keep an eye on the oil level.
And the water level too, as for me it seemed very thin and grey for oil.

Not my strong point but I wonder if [ref]colb[/ref], or someone similar may be able to advise whether this could be due to a blocked Crank Case Ventilation (CCV) system?
 
Blocked or gummed up CCV system couldbe an issue, pull the hose off the cam cover and see what state the inside is in, any build up of black oily carbon will need cleaning out or hoses replaced, follow the hoses down the system and check out their internal states and clean or replace if full of deposits. Valve stem oil seals may well have gone hard and not preventing oil to be sucked into the engine where it gets burnt, could be a cause of the black soot in the exhaust. If you do suspect valve stem seals, there is an additive you can add to the engine oil that reconditions the rubber and makes them seal better, not used any myself but people do say it works, worth a try to see if it improves things for little money. https://www.forteuk.co.uk/product/seal-conditioner/
 
[ref]Rachel!!!![/ref], I think [ref]colb[/ref] has some sound advice there. He's not the first to mention valve stem seals either.
I think it should be easy for you to check the CCV hose, but happy to help if you're not too sure.

Regards the product he mentions, it isn't too expensive in the long run but if you want to go that route I've noticed that Ebay sellers offer discounts for buying more than one. Vall's car is over 100k and 18 years old, so I'd have a tube of it too, as a precautionary measure.
 
You must log in or register to reply here.
Back
Top Bottom