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Black soot coming out of exhaust
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- Newbie
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- Location: Suffolk
Black soot coming out of exhaust
I have a 2006 2.5si on 66k
For the last 2 months roughly I've noticed black soot on the bumper above the exhaust and the tail pipes are black. It never did this before. It's not every time I drive and I think it's possibly when stuck in traffic. No other issues as far as I'm aware, no lights on dash, not using oil.
Is there something this is likely to be? Or anything I can check myself before taking it to a garage?
For the last 2 months roughly I've noticed black soot on the bumper above the exhaust and the tail pipes are black. It never did this before. It's not every time I drive and I think it's possibly when stuck in traffic. No other issues as far as I'm aware, no lights on dash, not using oil.
Is there something this is likely to be? Or anything I can check myself before taking it to a garage?
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- Lifer
- Posts: 3264
- Joined: Sun Feb 10, 2019 2:10 pm
- Location: Bristol/Bath
Black soot coming out of exhaust
Black smoke/soot is over-fuelling car running too rich... could be a number of things, need a code reader first to see if any faults thrown up
Alpina Roadster S Lux no. 204 (1 of 15 uk cars in Alpina Blue)
Previous Z4’s :E89 30i, E89 20i, E85 3.0Si (X4) E85 3.0i, E86 3.0 Si, E85 2.5si, E85 2.5i
Previous Z4’s :E89 30i, E89 20i, E85 3.0Si (X4) E85 3.0i, E86 3.0 Si, E85 2.5si, E85 2.5i
- colb
- Senior Member
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- Location: Newport, South Wales UK
Black soot coming out of exhaust
Running rich, with diagnostics take a look at live data from the fuel trims if they are high it could be down to a couple of reasons.
1. Air leaks in the vaccum system across the engine from post Maf to exhaust including all the CCV pipes, oil filler cap and dipstick tube O ring. Any split or holed rubbers should be replaced.
2. Faulty Maf, not registering the correct amount of air passing into the throttle body, if its over reporting the ECU will see this as a lean mixture much the same as extra air from holes or splits as in No.1. You could try cleaning the Maf with specific Maf cleaner spray, don't use anything else and don't touch the sensor with your fingers.
It is worth noting that if the electrical connection is disconnected the car will run on default settings, worth trying this to see if it makes any difference, with it disconnected take a loog at live data from the fuel trims see if they have dropped. If they have thats an indication that the Maf is at fault, Maf's dont always set fault codes EML lights tend to be triggered because something else upstream ao downstram of the Maf has detected something wrong.
Always good to do a smoke test on these engines to find any air leaks you can't find by visual checks.
1. Air leaks in the vaccum system across the engine from post Maf to exhaust including all the CCV pipes, oil filler cap and dipstick tube O ring. Any split or holed rubbers should be replaced.
2. Faulty Maf, not registering the correct amount of air passing into the throttle body, if its over reporting the ECU will see this as a lean mixture much the same as extra air from holes or splits as in No.1. You could try cleaning the Maf with specific Maf cleaner spray, don't use anything else and don't touch the sensor with your fingers.
It is worth noting that if the electrical connection is disconnected the car will run on default settings, worth trying this to see if it makes any difference, with it disconnected take a loog at live data from the fuel trims see if they have dropped. If they have thats an indication that the Maf is at fault, Maf's dont always set fault codes EML lights tend to be triggered because something else upstream ao downstram of the Maf has detected something wrong.
Always good to do a smoke test on these engines to find any air leaks you can't find by visual checks.
Z Shed Cymru member
1999 1.8 Z3
2003 2.5 Z4
1998 Honda Deauville 650
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1999 1.8 Z3
2003 2.5 Z4
1998 Honda Deauville 650
If the forum helped you, why not help the forum back. Thats the Z4 way!
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- enuff_zed
- Lifer
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- Location: Attleborough, Norfolk
Black soot coming out of exhaust
As always, colb has provided good advice. You may of course need to find someone with a suitable code reader.
Maybe worth mentioning where you are, to see if there is a forum 'expert' nearby who could help.
One more thing: was anything changed on the car around the same time that may have introduced this problem?
Maybe worth mentioning where you are, to see if there is a forum 'expert' nearby who could help.
One more thing: was anything changed on the car around the same time that may have introduced this problem?
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- Newbie
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Black soot coming out of exhaust
Nothing has been changed on the car however thinking about it at the begining of Feb when we had all that snow the car Sat for about 5 days and wouldn't start. I tried jump starting it which got there in the end after a few tries but it didn't seem like it was the battery at fault, it's also a new battery and I've had no battery issues before or after that. I wondered at the time if snow had drifted in the front grill? I'd stupidly parked it so that could happen. I have no idea if that could explain it but it did start with the soot after that, I'm not sure how long after or if that could have done anything?
I'm in Suffolk but not far from the Norfolk border near Diss. I don't have a code reader so if anyone does around this way that would be very handy otherwise it will have to go to a garage.
I'm in Suffolk but not far from the Norfolk border near Diss. I don't have a code reader so if anyone does around this way that would be very handy otherwise it will have to go to a garage.
- enuff_zed
- Lifer
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Black soot coming out of exhaust
Well I'm in Attleborough so not too far from you, and do have a code reader you are welcome to borrow.Rachel!!!! wrote: ↑Fri Apr 16, 2021 11:04 am Nothing has been changed on the car however thinking about it at the begining of Feb when we had all that snow the car Sat for about 5 days and wouldn't start. I tried jump starting it which got there in the end after a few tries but it didn't seem like it was the battery at fault, it's also a new battery and I've had no battery issues before or after that. I wondered at the time if snow had drifted in the front grill? I'd stupidly parked it so that could happen. I have no idea if that could explain it but it did start with the soot after that, I'm not sure how long after or if that could have done anything?
I'm in Suffolk but not far from the Norfolk border near Diss. I don't have a code reader so if anyone does around this way that would be very handy otherwise it will have to go to a garage.
However, I am no expert, so once we got codes I would still be relying on the kind people on here to help advise.
I'll PM you my mobile if you fancy a run out this way to check it?
- enuff_zed
- Lifer
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Black soot coming out of exhaust
colb, can you give any pointers as to what we should be looking at regarding codes etc.
I would make a note of all the ones showing, then reset and see what comes back.
I have an Autophix5900 which seems pretty comprehensive in its functions.
Just knowing which areas to look in would help a bit.
So far only used it on wifey's 2.5i which is the M54 engine, so not sure what differences there might be.
EDIT: Also, if the front grille was full of snow, is it likely that got dragged into the intake when the engine finally started and may have caused an issue.
For example, maybe now the air filter is a soggy mess?
I'm thinking, maybe it is worth whipping the air filter out first and checking there's no debris etc in there too?
Its a simple check to eradicate that as a problem.
I would make a note of all the ones showing, then reset and see what comes back.
I have an Autophix5900 which seems pretty comprehensive in its functions.
Just knowing which areas to look in would help a bit.
So far only used it on wifey's 2.5i which is the M54 engine, so not sure what differences there might be.
EDIT: Also, if the front grille was full of snow, is it likely that got dragged into the intake when the engine finally started and may have caused an issue.
For example, maybe now the air filter is a soggy mess?
I'm thinking, maybe it is worth whipping the air filter out first and checking there's no debris etc in there too?
Its a simple check to eradicate that as a problem.
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- Newbie
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Black soot coming out of exhaust
Thanks for your number, that would be great if I could come over and see what codes we get. I'll send you a text later. I will also have a look at the air filter this afternoon when I get home from work and check that.
- enuff_zed
- Lifer
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Black soot coming out of exhaust
No problems. Hope I can actually help..........Rachel!!!! wrote: ↑Fri Apr 16, 2021 12:34 pm Thanks for your number, that would be great if I could come over and see what codes we get. I'll send you a text later. I will also have a look at the air filter this afternoon when I get home from work and check that.
- Argyll Andy
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Black soot coming out of exhaust
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- enuff_zed
- Lifer
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Black soot coming out of exhaust
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- colb
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Black soot coming out of exhaust
Code read it and see what comes up, good idea to check the air filter also have a good look at all the rubber intake bellows and all vaccum hoses and plastic pipes for splits or holes that could be the cause of the rich running as it may be seeing unmetered air that has not been measured by the Maf, when it gets picked up in the exhaust it thinks its running lean so adds more fuel to compensate. If it is doing that then looking at the fuel trims to see if they are high would add to the suspicion of air leaks or bad Maf. Its worth noting that over fueling will eventually trigger the EML to indicate something is amiss, bad Maf's dont always set codes or light the EML. A smoke test is a sure fire way of finding any air leaks that can't be found visually. Clear any codes you find after all these checks have been made and give the car a run then rescan and see if any codes return.
Z Shed Cymru member
1999 1.8 Z3
2003 2.5 Z4
1998 Honda Deauville 650
If the forum helped you, why not help the forum back. Thats the Z4 way!
https://www.paypal.com/cgi-bin/webscr?c ... source=url
1999 1.8 Z3
2003 2.5 Z4
1998 Honda Deauville 650
If the forum helped you, why not help the forum back. Thats the Z4 way!
https://www.paypal.com/cgi-bin/webscr?c ... source=url
- enuff_zed
- Lifer
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- Joined: Wed Oct 26, 2016 11:05 am
- Location: Attleborough, Norfolk
Black soot coming out of exhaust
Cheers. Look like we'll be getting together at some point to take a look. It may be a case of sending you some before and after codes if we can't find anything.colb wrote: ↑Fri Apr 16, 2021 1:41 pm Code read it and see what comes up, good idea to check the air filter also have a good look at all the rubber intake bellows and all vaccum hoses and plastic pipes for splits or holes that could be the cause of the rich running as it may be seeing unmetered air that has not been measured by the Maf, when it gets picked up in the exhaust it thinks its running lean so adds more fuel to compensate. If it is doing that then looking at the fuel trims to see if they are high would add to the suspicion of air leaks or bad Maf. Its worth noting that over fueling will eventually trigger the EML to indicate something is amiss, bad Maf's dont always set codes or light the EML. A smoke test is a sure fire way of finding any air leaks that can't be found visually. Clear any codes you find after all these checks have been made and give the car a run then rescan and see if any codes return.
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- Newbie
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Black soot coming out of exhaust
The air filter is definately ok, it's dry and clean.
I had a friend look at all the plastic hoses and pipes etc and he said everything looks brand new and definately doesn't look like any problems there. He queried if it could just be short journeys? At the min I'm mostly just driving 7 miles each way to work a day. Could it be that?
I had a friend look at all the plastic hoses and pipes etc and he said everything looks brand new and definately doesn't look like any problems there. He queried if it could just be short journeys? At the min I'm mostly just driving 7 miles each way to work a day. Could it be that?
- rdm05z4
- Member
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- Location: Columbia MO USA
Black soot coming out of exhaust
Continual short drives are not good for a car. It does not really get up to optimum temperature. I would get the car scanned as you have planned per OP. But I would also make sure to run "high test" gas in it if you have not been doing it. There are also additives you can add to your tank of gas to help clean out any sludge from the short trips. Would take it for a long spirited run after doing these things. Good luck with your issue.
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