Excessive Smoke is Caused By ....

Turbo Steve

Top Post Dawg
Joined
Jan 11, 2000
Location
.
All diesel engines will have some smoke due to their inherent design. However, EXCESSIVE smoke is not normal and is basically caused by incomplete combustion due to one or more of the following:

* Low Quality Diesel Fuel
* OK Diesel Fuel with Low Cetane Rating
* Injection Timing is Improperly Set
* Dirty, Leaking, or Faulty Injectors
* Faulty Injection Pump
* Leaking or Faulty Turbocharger
* Excessive Exhaust Back-pressure
* Too Much Fuel for ECU Software to Handle
* Too Little Air / Intake Air System is Clogged
* Faulty EGR System
* Faulty CCV System
* Wornout Valve Guides Suck Oil into Combustion Chamber
* Faulty ECU
* Faulty N-75 Convertor Valve
* Use of Wrong Engine Oil
* Oil is too Contaminated or Dirty to Adequately Seal Piston Rings
* Broken or Stuck Piston Rings
* Glazed Cylinder Walls
* Burned or Bent Valves
* Bad or Incorrectly Installed Head Gasket
* Low Compression
* Improper Camshaft to Crankshaft Alignment
* Badly Worn Timing Belt or one that's Skipped a Tooth
 

Turbo Steve

Top Post Dawg
Joined
Jan 11, 2000
Location
.
The color of smoke emitted from the tailpipe of a modern TDI diesel engine can denote specific indications of problems or lack thereof.

For example:

White smoke during a cold start is usually indicative of a little condensation / moister in the engine or exhaust system. In most cases this is somewhat "normal" according to VW, even though most of it can be corrected with a good additive and cetane booster.

Blue smoke usually indicates oil that gets into the combustion chamber and is burned (for one reason or another). It is also considered "normal" for a diesel engine to burn a little bit of oil, including the TDI with tighter piston to cylinder bore clearances, which naturally reduces the amount of oil consumption.

Black smoke indicates too much fuel or too little of air within the combustion process. This could also result from poor injection timing as well or from a Forum member rapidly stepping on the accelerator pedal to give a tailgator a "smokey!"


No smoke at all indicates that you are probably doing many things right and should stay with your outlined maintenance plan that appears to be working. Furthermore, the quality of diesel fuel plays a large role in the color of smoke or lack thereof during a cold-start.

Now back to "white smoke," which also can occur when there is not enough heat to burn the fuel. The unburned fuel particles go out the tailpipe and typically produce a rich fuel smell. It's not unusual to see white smoke in the exhaust during cold weather until the engine warms up.

Moreover, with very littly heat and white smoke, bad glow plugs or a faulty glow plug control module can cause somewhat excessive white smoke on engine start up. Low engine cranking speed may also produce white smoke on occasion too.

If white smoke is still visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timing, a worn injection pump, or coolant is somehow getting into the combustion chamber. Low compression producess less heat than normal and can also be a source of white smoke. And finally, according to my local Bosch Injection Center, air in the fuel system can cause extra white smoke as well.

In conclusion, a puff or two of white smoke during a coldstart is normal. Very little or no smoke is rare and confirms your engine is close to performing at peak efficiency. Blue or black smoke can be warning signs of inefficiency or a TDI'er moving with a purpose!


[ December 20, 2001: Message edited by: Turbo Steve ]</p>
 

Dorado

Veteran Member
Joined
Jun 24, 2001
Location
Pittsburgh, PA
TDI
New Beetle TDI, 2002, Cool White
Thanks for the post. What about smoke (apparently white) that is only seen (a) at night under the lights of the car directly behind and (b) when accelerating from a standing stop unto highway speed. That's the only smoke we've seen.
 

peter pyce

Veteran Member
Joined
Nov 6, 2001
<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Dorado:
.......What about smoke (apparently white) that is only seen (a) at night under the lights of the car directly behind ....<hr></blockquote>

My smoke is black, but in the night as described by you, looks white ..... I guess every color of smoke in that situation will look kind of white as you have close to white color lights behind.

peter
 

Dorado

Veteran Member
Joined
Jun 24, 2001
Location
Pittsburgh, PA
TDI
New Beetle TDI, 2002, Cool White
Indeed, we have started blending in 1/2 gal of SoyPower Biodiesel with every tank (that's 3.5%). This immediately had a positive effect in terms of lubricity, as we could tell from the engine sound. But we can still see the smoke at night etc. when accelerating hard. We'll try a higher dose of BD with the next tank and see. Unfortunately, for the time being we don't have access here to good petro-diesel.
 

garrettp

Former Chip-Monk
Joined
May 23, 2000
Location
Oconto, WI
TDI
2000 JEDI
i used to be the soot king (along with VDubTDI) and i started to use 47-summer/50-winter fuel locally and 16oz. of Power service each tank. now i cannot get the dang thing to soot at all
. i actually miss it
 

a32e5s7

Veteran Member
Joined
Mar 28, 2010
Location
Saint Louis, Missouri
TDI
None
There is more information that can be added to this subject, I wish people who are very knowledgeable could pitch in a bit of their knowledge.

Could someone explain why a faulty injection pump can cause excessive smoke? What goes wrong with ip that it causes smoke?
 

Bob_Fout

Oil Wanker
Joined
Sep 5, 2004
Location
Indiana
TDI
2003 Jetta - Alaska Green (sold) / 2015 GTI 2.0T
There is more information that can be added to this subject, I wish people who are very knowledgeable could pitch in a bit of their knowledge.

Could someone explain why a faulty injection pump can cause excessive smoke? What goes wrong with ip that it causes smoke?
I'm no expert but: wrong injection timing, as well as injection quantity, can cause smoke. (different color smoke, though). IP can affect both of these.
 
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