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General => General discussion => Topic started by: Sugar79 on 23 January 2005, 15:19

Title: Black smoke
Post by: Sugar79 on 23 January 2005, 15:19
is that carbon build up? my mk4 2litre Gti is throwing out abit of black smoke  when you put your foot down, (and the cat is smelling also) and drinking quite alot of fuel  :sad:
I think its running rich, its due for its service, anyone got any ideas?
thanx
Title: Re: Black smoke
Post by: kniterider on 23 January 2005, 15:30
overfueling due to a blocked air filter or possible MAF (common mk4 prob) prob..... see how it is after your service. if still the same and using unusual amounts of fuel sounds like your MAF sensore is knacked, you can try cleaning with a solvent spray, but dosnt work in the long run, think vw do them for about ?85 exchange......

kid
Title: Re: Black smoke
Post by: Sugar79 on 23 January 2005, 15:40
ive had a new maf fitted last month as the car felt like it was a tractor lol, the car hasnt lost any power and its had new plug n oil, checked the air filter and it wasnt blocked or all that grubby.
Title: Re: Black smoke
Post by: kniterider on 23 January 2005, 15:47
think its either getting coked up then when you driving steady, or its overfueling when you floor it, unless the smoke is blue and not black??, if so then its burning a bit of oil, but thats nothing to worry about as some mk4's (2000cc 8v's) use loads of oil..

id still wait and she how it goes after your service

kid
Title: Re: Black smoke
Post by: Sugar79 on 23 January 2005, 15:50
ok will do, thanx... just worried that it mite of been something expensive lol  :smiley:
Title: Re: Black smoke
Post by: kniterider on 23 January 2005, 15:54
if youve had a new MAF fitted then that is prob the worst expense in trying to rectify the prob, over fueling could also be caused by a engine temp sender which tells the ecu how hot the engine is and then adjusts the fueling accordingly, these can fail and they can run rich and use more fuel also, but as i said see how it goes after your service!!!

kid

Title: Re: Black smoke
Post by: audiquattro on 25 January 2005, 01:04
I wouldn't leave it too long as overfuelling will destroy your cat.
Title: Re: Black smoke
Post by: Sugar79 on 25 January 2005, 11:40
Iam hoping the garage can fit me in later this week  :smiley:
Title: Re: Black smoke
Post by: audiquattro on 25 January 2005, 12:20
I would say its likely to be the engine temp sender that is a fault, as you have already replaced the MAF.
Title: Re: Black smoke
Post by: Sugar79 on 25 January 2005, 12:36
but the temp on my dash stays at 90 when it warms up? and looking at the prevous history of the car from the last owner it had a temp gauge sender unit back in july 2003, would it really need replacing again?  :undecided:
Title: Re: Black smoke
Post by: topher on 25 January 2005, 12:38
lambda (sp) sensor ?
Title: Re: Black smoke
Post by: Sugar79 on 25 January 2005, 12:47
erm what that? lol
Title: Re: Black smoke
Post by: audiquattro on 25 January 2005, 12:48
but the temp on my dash stays at 90 when it warms up? and looking at the prevous history of the car from the last owner it had a temp gauge sender unit back in july 2003, would it really need replacing again?? :undecided:

There is usually a separate coolant temp sensor for the ECU.
Could also be a faulty lambda probe.
Topher should be able to tell you more, as he owns a mk4 ?:wink:
Title: Re: Black smoke
Post by: audiquattro on 25 January 2005, 12:50
The lambda probe sits in the exhaust manifold or front of the cat, it reads the oxygen content in the exhaust gases, and sends a voltage signal back to the ECU. This allows the ECU to re-adjust the fuel/air mixture to suit.
Title: Re: Black smoke
Post by: Sugar79 on 25 January 2005, 12:51
gosh all these god damn sensors are doing my head in lol  :laugh:
are they expensive? :sad:
Title: Re: Black smoke
Post by: audiquattro on 25 January 2005, 12:53
Coolant temp sender should be expensive, not sure about the lambda probe, could be costly  :laugh:
Title: Re: Black smoke
Post by: Sugar79 on 25 January 2005, 13:00
god damn  :cry: seems like all my sensors are going down  :cry: