Smoking more than normal

[ashb 130 tdi]

Hi guys,

I know this topic has been brought up many times before about diesels being smokey however I cannot really find anything on here that is the same as my problem.

Basically, I have had a de-cat exhaust on for about a month with no problems (e.g excessive smoking) but I got home from a 160 mile motorway trip on Monday and noticed that when driving at low speeds and low revs it is smoking like crazy, a light grey smoke, but when I put my foot down and go over 2k revs it seems to stop. There doesn't seem to be any loss of power, mpg is the same, oil level is fine, coolant is fine so I am really not sure what it could be? It is getting quite embarrassing now as when I am driving at 30 in a built up area it is smoking really bad!

Any ideas would be greatly appreciated! (car is a cupra tdi by the way)

Cheers

 

[Shunky]

I know it's not much help but I had the same issue - even after I replaced the turbo it still smoked quite badly. Put the cat back in and hey presto no problems what so ever! So now left with a decat sitting in shed I cannot use until a) find a resolution b) spend muchos pesos with Darkside on a bigger tubby. I have a funny feeling it's someting to do with the way the standard tubby reacts with the decrease in back pressure.

 

[ashb 130 tdi]

Hi Shunky,

Thanks for the info. I de-catted my old 130 tdi but never had any issues with excessive smoke but I did retain a back box on that one whereas I have got a straight through pipe on the Cupra so not sure if this is the reason why? I just don't understand why it was fine for a month and then suddenly started smoking really bad one day!

 

[Seatmann]

You're not getting enough turbo in the lower revs for some reason I think, lack of turbo and to much fuel. Maybe a leaky vacuum pipe somewhere, it could be a tiny one too but as the vnt turbo uses vacuum to actually make boost a tiny leak is all it takes to upset things.

 

[ashb 130 tdi]

Thanks for the reply Seatmann! That does make sense about a possible boost leak as had one on my old car and it smoked really really bad and I lost power altogether in the end. It must be a small leak as you say as I cannot hear any hissing like I did on my old car. I don't suppose you know an easy way of finding the source of the leak??!! Or have I just got to wait until it gets worse and more obvious where the leak is?!

 

[Seatmann]

You could try using a piece of tubing like a stethoscope, one end in your ear then trace the vac lines with the other.

 

[ashb 130 tdi]

Further to the above, not had chance to get the car into a garage yet due to work. Was driving to work today and doing about 80 mph in 6th when the car appeared to go into limp mode. Car would not accelerate past 3k rpm. Took it easy for the rest of the journey to work and noticed that the exhaust note seemed a lot louder. Got to work, let the engine cool down and turned it off. Started it up again and car sounded normal and revved as normal??! Took it easy on the way home, still smoking quite a lot, but have now noticed a leak underneath the engine but not sure what it is?? Has anyone got any ideas what the problem might be before taking it to the stealers?! Could it be a boost pipe problem?

 

[Seatmann]

Could be a number of things but you've now hit limp mode, that's where you restart the engine and the power's back. Could be a boost leak, vac leak, bad N75 solenoid, map sensor, sticky turbo vanes etc, fault codes might help narrow it down.

 

[ashb 130 tdi]

Thanks for the reply Seatmann! Will it have to be a visit to the stealers then or can a 'normal' garage help?!

 

[Seatmann]

Anyone with vagcom or other suitable scanner can do it.

 

[Dezeze]

Happened to mine recently, turned out it was the 3 mm hosing from the turbo to maf etc that had perished over time. Very hard to notice, but may be worth checking just in case! (especially if its the braided hose, the braid usually hides where it's perished!)
Good luck dude!

 

[ashb 130 tdi]

Thanks for the replies guys. Taking her to the garage tomorrow so will see what the outcome is but will bear in mind what u have said incase they try to rip me off!! Will let u know how it goes!!

 

[ashb 130 tdi]

Well took her to he garage today and they cannot find any faults on diagnostic so I am stumped now! Garage seem to think it may be the turbo vanes but aren't sure.

 

[cheshire cat]

Thanks for the reply Seatmann! That does make sense about a possible boost leak as had one on my old car and it smoked really really bad and I lost power altogether in the end. It must be a small leak as you say as I cannot hear any hissing like I did on my old car. I don't suppose you know an easy way of finding the source of the leak??!! Or have I just got to wait until it gets worse and more obvious where the leak is?!

don't confuse what he just said vac leak is not a boost leak and a tiny one does make a big difference

 

[ashb 130 tdi]

Apparently the turbo has had it. The oil feed pipe was blocked and the turbo wasn't getting any oil so it's knackered now! £900 for a new turbo, does that sound about right???!

 

[Seatmann]

Sounds way to much to me from everything I've read and heard. Shop around, check out what other folk are buying, try the companies on the home page on here etc.

 

[mk4 cupra]

Too me mate I'd cheak it your slef if ur turbo was knackerd it would smoke all the time not just at low revs my Cupra pd160 is also doing the same thing urs is doing write now and the cause of the fault it the boost pipe at the base of the turbo is leaking and knackerd so if I was u I'd that cheated first before u jump in and change a turbo

 

[cheshire cat]

Apparently the turbo has had it. The oil feed pipe was blocked and the turbo wasn't getting any oil so it's knackered now! £900 for a new turbo, does that sound about right???!

well anythings possible, did they remove it before the diagnosis ?? or are they guessing (again) I think unless you trust them- I would get someone else to take a look for pref' a diesel specialist

 

[ashb 130 tdi]

Yeah they removed it before diagnosing it and said that it was beyond repair due to the lack of oil it had been receiving and therefore needs to be replaced. I know I should really shop around and try to get a second opinion but I don't work local to where I live so it's a pain trying to sort things and I need the car for work so I suppose I am just gonna have to pay it! Thanks for all the info anyway guys!

 

[mk4 cupra]

If ur turbo was that bad it would not be running at all u would have no power massive smoke and no boost pressure so I still belive there trying to pull a fast one