Black smoke when accelerating/ revving

[Zowen]

So I have a BMW z4 e85 (53 plate) and it is running rich (burning too much fuel) and when I accelerate or rev black smoke comes out the exhaust this is only during the acceleration and when holding speed doesnt appear to be a noticeable amount.

Theres definitely a rich fuel smell and I was wondering if anyone had this problem and ways they go about fixing it I heard its usually a bad fuel injector, bad air intake or exhaust isnt letting enough air flow but am unsure on testing these without replacing them any help would be greatly appreciated.

Thanks

 

[enuff_zed]

Which engine do you have?

 

[inkey$]

No evidence, but why did the answer to this in my head immediately assume 2.0?

 

[Zowen]

Which engine do you have?

Sorry I have the 3.0

 

[inkey$]

How long have you had the car? Sounds like the exhaust is massively coked up, but it’s likely more complex than that. Is the car getting through much oil? Maybe it needs a proper blast after checking the levels

 

[Zowen]

How long have you had the car? Sounds like the exhaust is massively coked up.

Ive had the car about 2 months now, bought as a project to do up for summer but was mostly mechanically sound just body and interior needing doing. Oil level has been fine and had a big replacement cant remember exact name but was a £400 job (sorry my memory is bad) all levels havent dropped a bit but I know 2 months isnt much go by but done about 4k miles in this time.

 

[enuff_zed]

Be handy if you could remember what was replaced as it could have disturbed something.
With respect, perhaps see if a member is nearby who could check it out, codes etc.

 

[deltasierra]

You need a code reader then work through the troubleshooting routine, if it idles smoothly check TPS, Air flow sensor and Temperature sensor.

 

[Zowen]

Be handy if you could remember what was replaced as it could have disturbed something.
With respect, perhaps see if a member is nearby who could check it out, codes etc.

got a code reader only code its throwing is thermal oil sensor, except i think thats just a loose connection as it is working and if i clear the code it stays off for ages.

 

[enuff_zed]

Be handy if you could remember what was replaced as it could have disturbed something.
With respect, perhaps see if a member is nearby who could check it out, codes etc.

got a code reader only code its throwing is thermal oil sensor, except i think thats just a loose connection as it is working and if i clear the code it stays off for ages.

Fair enough.
What was replaced? I'm assuming an engine component?
If, for example, an intake pipe hasn't quite been refitted properly the mixture will be affected and it will run excessively rich.
However, I would expect to see codes relating to mixture or O2 sensors in this case.

 

[Zowen]

What was replaced? I'm assuming an engine component?

Sorry I went through the documents here was what was replaced

 

[enuff_zed]

Nothing there that seems obviously linked tbh.
Forgive me if this sounds rude, but are you sure the smell is fuel, not oil?
Is it using any oil?

 

[Zowen]

Nothing there that seems obviously linked tbh.
Forgive me if this sounds rude, but are you sure the smell is fuel, not oil?
Is it using any oil?

Definitely fuel its only when I rev it hard does it do it read online usually to a poor mix of fuel and air, or not enough air getting in or out. Oil level hasnt dropped at all Ive been checking regularly

 

[deltasierra]

Be handy if you could remember what was replaced as it could have disturbed something.
With respect, perhaps see if a member is nearby who could check it out, codes etc.

got a code reader only code its throwing is thermal oil sensor, except i think thats just a loose connection as it is working and if i clear the code it stays off for ages.

If that oil sensor thinks the engine is cold it will enrich the mixture, like running on choke, if it’s a sensor or a wiring fault it needs fixing
Some of the fault codes take a long time to register to avoid short term variations turning the engine light on

 

[colb]

Ignore the oil level sensor they are a regular fail, it won't affect the running engine just set a code. Of your sure it's fuel related then view fuel trims in love data to see what it's doing. High fuel trims often caused by vaccum leaks from holes or splits in intake boots and hoses across the engine. Smoke test will find any that can't be found on a visual check If the smoke when running is black and oily then you might be looking at worn piston rings and bores andaybe valve guides. The latter is the cause of oily smoke on the overun as the engine slows down worn guides will allow oil Tobe sucked down the guides and get burnt in the cylinders.

 

[deltasierra]

Ignore the oil level sensor they are a regular fail, it won't affect the running engine just set a code. Of your sure it's fuel related then view fuel trims in love data to see what it's doing. High fuel trims often caused by vaccum leaks from holes or splits in intake boots and hoses across the engine. Smoke test will find any that can't be found on a visual check If the smoke when running is black and oily then you might be looking at worn piston rings and bores andaybe valve guides. The latter is the cause of oily smoke on the overun as the engine slows down worn guides will allow oil Tobe sucked down the guides and get burnt in the cylinders.

The OP refers to a “thermal oil sensor” is this the oil level sensor and there is no oil “temperature” sensor

 

[Zowen]

Hi Ive found the problem! fuel injectors leaky and they shoot fuel everywhere! 2 fuel injectors where faulty and I want to check the pump as well. I havent fixed it yet so don't know 100% if this will solve the problem but Id imagine so.

 

[Zowen]

The OP refers to a “thermal oil sensor” is this the oil level sensor and there is no oil “temperature” sensor

Sorry yes I ment oil level sensor, reading off a poorly translated german OBD reader

 

[enuff_zed]

Hi Ive found the problem! fuel injectors leaky and they shoot fuel everywhere! 2 fuel injectors where faulty and I want to check the pump as well. I havent fixed it yet so don't know 100% if this will solve the problem but Id imagine so.

Sounds like that's your problem.
Think I'd be tempted to change all of the injectors if you can afford to.
Don't worry about the pump just yet.

 

[Zowen]

Hi Ive found the problem! fuel injectors leaky and they shoot fuel everywhere! 2 fuel injectors where faulty and I want to check the pump as well. I havent fixed it yet so don't know 100% if this will solve the problem but Id imagine so.

Sounds like that's your problem.
Think I'd be tempted to change all of the injectors if you can afford to.
Don't worry about the pump just yet.

Was planning on it if 2 are faulty im assuming there both quite old so I'll change all of them and keep the 4 none leaky after i check the resistance just incase.
Do you reccomend any fuel injectors?