Black Smoke

[pe3te]

hello all

i have a 1998 1.9 tdi 140,000 miles and have noticed that i now get a lot of black smoke under hard acceleration in 1st and 2nd gear when pulling away quickly

anyone have any ideas what could be causing this

regards

pete

Edited August 6, 2011 by pe3te

[gregers]

oil change needed maybe?

 

mine does this when its getting time for an oil change.

[Scorpiorefugee]

The old money used to be on - Black smoke = fuel, Blue smoke = oil. Smoke from oil usually comes in at high revs and overrun so my guess is fuel. If you are new to these motors you will have no idea what they are capable of but I never needed to floor my old 98 110bhp in low gears and it would return 45mpg almost permanently. It could be that you are expecting too much or you have a problem. As a guide, mine would do 50 to 70 in fifth in around 10 seconds with no smoke (that I could see anyway) and it never used any oil right up to 250,000 miles. Try clean oil, as Greggers has said, run it low and fill up with good fuel, shell and not supermarket stuff and drive it gently. You should get 550 to 650 miles before the fuel light comes on on a run. They do get thirsty over 70. If the performance isn't there you could have a Turbo problem (that could explain the smoke) or a duff MAF (Look in the FAQs). If you can give a bit more info based on the above it would help to make sense of any advice.

[seatkid]

Its most likely just coked up injectors and an accumulation of soot in the exhaust system.

 

Coked up injectors give poor spray patterns that lead to incomplete combustion and hence black smoke. Just use an injector cleaner additive. Millers Diesel Ecomax gives good results provided you use it for several tanks - its quite gentle and so takes several tankfuls to finish cleaning bad cases, but that's good as you don't want to detach lots of carbon from your head and crowns all at once. Be prepared for the smoke to initially increase substantially when using a cleaning additive. If you want to speed the process, run a couple of tanks at double the normal dose.

 

At the same time give the girl several Italian tune ups to clear the exhaust system - I find the most effective method is driving at 1500 rpm in 3rd - then floor it and take it to the red line and immediately back off and slow down. Repeat 3 or 4 times. This technique ensures max turbo boost is developed, although it backs off when you approach max revs. If you check the rear view mirror you will see max smoke in the 2000-3000 rpm range. (don't spend too long looking in the mirror though!)

 

Repeat the Italian tune up every few days until you see an improvement.

 

IMPORTANT: Before you do any Italian tune ups - check your engine/cambelt is up to it (i.e. the belt or idlers are not overdue replacement and the oil is not past its change by date and all levels are correct) Also ensure your engine is up to temperature before any run.

PLEASE! Have consideration for other road users (drivers and pedestrians) and don't do any Italian tune ups in built up or residential areas! Only do tune ups when there is no traffic and its safe to do so and on roads that allow 70mph :)

 

 

Finally - change the engine oil as a smoking engine will have also loaded the oil with a much higher level of soot and all oils have a limit on the amount of soot they can suspend.

 

P.S. Check you air filter is reasonably clean. A blocked filter can lead to smoke under load - although the MAF is there to stop that happening.

Edited August 6, 2011 by seatkid

[pe3te]

The old money used to be on - Black smoke = fuel, Blue smoke = oil. Smoke from oil usually comes in at high revs and overrun so my guess is fuel. If you are new to these motors you will have no idea what they are capable of but I never needed to floor my old 98 110bhp in low gears and it would return 45mpg almost permanently. It could be that you are expecting too much or you have a problem. As a guide, mine would do 50 to 70 in fifth in around 10 seconds with no smoke (that I could see anyway) and it never used any oil right up to 250,000 miles. Try clean oil, as Greggers has said, run it low and fill up with good fuel, shell and not supermarket stuff and drive it gently. You should get 550 to 650 miles before the fuel light comes on on a run. They do get thirsty over 70. If the performance isn't there you could have a Turbo problem (that could explain the smoke) or a duff MAF (Look in the FAQs). If you can give a bit more info based on the above it would help to make sense of any advice.

 

 

i totally agree with every thing you said and just done 700 miles on a full tank of diesel (esso garage)whilst on holiday 360 motorway miles and the rest on a & b roads, i have not noticed any power loss and i only noticed the problem when pulling out onto a fast single carrigeway a road and happened to look in the mirror to see if any one was fast approching me behind.

Now i know of the problem i find myself just checking to see if its fixed itself.

[Scorpiorefugee]

It sounds like you don't have much to worry about. The only time I did see a bit of smoke from my old Gal was a couple of times when I accelerated hard after a bit of overrun when there would have been nothing coming out of the exhaust and nothing to drive the turbo. About a couple of seconds lag to get the turbo up to speed, just a wee bit of black haze and done. It may well have been something odd with all of the clever plumbing but it always went well, started on the button, even in winter with no glow plugs. (This was a problem I didn't know that I had until I found out that it was linked to something else that had always been odd but not enough to worry about.- faulty temperature sender causing the fan to come on after switching off)