Car Smoking Possible EGR?

[Timbo267]

HI All,

I am trying to figure out what is wrong with my GF Mk7 Fiesta 1.4 TDCI. It has an intermittent smoking issue where it pours white smoke out of the exhaust. It happens under idle when the car is warm and get worse under load. I have recently serviced the car to rule out anything silly but issue still occurs. A friend of mine read the codes on the car and it threw up a fault with the MAF sensor so I replaced it but issue still persists. I was told to check the EGR and EGR cooler as this may be the issue. I don't know where these are located on this model so if someone could help with that it would be really appreciated? If anyone has any idea on what the issue could be please could you give me some guidance as I am really stuck at the moment. 

[nicam49]

White smoke CAN be a very worn turbo. The check is to pop the pipe off and waggle the impeller to check how much play there is... should be a little, but not excessive. Another cause is overfuelling injector(s) resulting in unburnt fuel. Yet another cause is low compression... usually seen after you've driven through flood water and it's sucked in some via the air filter and as water doesn't compress, it's caused the conrods to bend and damage to the rockers and valves. ... check the air filter to see if its wet. 

Of course, if the head gasket has gone then the white smoke is the coolant... but usually you'll notice by loss of coolant, and it's rare on diesels for cylinder head gasket failure. 

If its got an egr cooler that's failed I  think you'll see loss of coolant. 

[Timbo267]

Thank you!!!! No oil and water mix so I think Head Gasket is ok. I will check turbo later and see if there is any play. I had heard about injector's also. Would they need replacing if they are the issue? I saw something about injector seals causing smoking issues so not sure if this could be the case although there is no buildup around the injectors. The issue is very intermittent so quite difficult to replicate when I need to. 

[TomsFocus]

Headgaskets rarely fail between oil and waterways nowadays.  It's more common to be between cylinder and waterway, which then creates steam in the exhaust.  The EGR cooler fails in the same way, allowing coolant into the exhaust.  You can have a sniffer test done on the coolant to check if there are any exhaust gasses present.  Or a pressure test done to check that the system holds pressure well.  You should also notice some coolant loss if that's the issue though.

White smoke from a turbo is often due to a failed exhaust oil seal, which you won't be able to see without removing the cat.  But you should notice some oil loss if that's the case.  Just for reference, I lost about 2 litres in 10 miles when mine failed and couldn't see any cars behind me, it was pretty noticeable! 

I would also suspect injectors to be at fault here tbh, either injector seals or one or more injectors worn.

[Timbo267]

That is really helpful information thank you! I'm still trying to work out what is happening. I haven't had much time this week to look at it. I will have a look tomorrow and check coolant and oil levels. Is there any way to test the injectors or would I just have to replace them and see what happens? 

[TomsFocus]

Yes, injectors can be tested electronically via diagnostics and physically using a leak off test. 

The injector seals can be visually checked for carbon deposits and often produced a 'chuffing' noise when leaking as well.

[Timbo267]

Thank you mate really appreciate it.