Causes Of Lean Running

[DamirGTI 325]

AFM seems to be fine .. though there is a two white areas/spots on the track , also , checking the wiper track more precisely is better with an analogue multmeter (it's slower so the readings are more accurate)

 

If the volt readings measured by the lambda sensor are now good across the rev range , the whitish plug discoloration can then only be down to the fuel type , spark plug heat range grade , engine mechanical problem - oil consumption ( it leaves whitish/yellow deposits on the spark plug tip also when oil is burnt inside the combustion chambers .. mainly residue from burnt engine oil additives which color the spark plug tip white/tan/yellow ..)

 

Or cod be just the photo issue ?! gray/grayish is good , white - no !

 

Which plugs are you using ? also , does the engine "consumes" oil ?

 

D

[roccorich 16]

Plugs are NGK BCP7ES.

 

Fuel is shell vpower

 

Ive not really had the car long enough to be sure on oil consumption, might have a leak from the dizzy as its all wet down that side but the level hasnt drastically dropped.

 

I compression tested it when I first got it and it and it built up to over 10 by the 3rd crank. That was on a cold engine with the throttle closed as I didnt read the Haynes book properly.

 

Ill have another close look at the wiper track as I didnt see any white parts before may just be the video.

 

Ill try and get the plugs out in the daylight sometime.

 

Ill work out my miles per gallon after I fill up next to see how thats looking.

 

Cheers

 

Rich

[DamirGTI 325]

7 grade NGK is fine for that engine ..

 

Just for the sake of the "photo color" , this one is 1.9 8v exhaust valve so by position it's closest to the spark plug on the head (picture is taken with expensive professional camera ) :

 

 

.. it's taken from the engine which had good air/fuel mixture , color is the same on the valve head as on the under head - gray , and the spark plug tips where also gray to light brown/tan .

 

D

Edited November 18, 2013 by DamirGTI

[roccorich 16]

Well over the last 200 miles of motorway driving Ive had 30mpg so I dont think it can be running too lean.