Please help!! Nissan Sunny B310 fine tuning the carb

[mr.ahamed]

Hi there,

My dad owns a nissan sunny b310 and its been with our family for the last decade. The car all in all is quite alright and runs okay with a general mileage of about 12kmpl.

In recent times with the implementation of these eco tests, it has been failing miserably despite what adjustments i do. They ask me to clean air filters, adjust ratios, clean plugs. Im just so confused. 

Water literally drips from the exhaust so i don't really see it out of tune.

Even today i went to get an eco test done and they failed the first attempt saying the fuel flow is a bit too much and that i should clean my air filters. I have no idea how a car so smooth manages to fail like that. 

Please if anyone knows a place where i can have this properly looked at and tuned to pass these tests it would be great.

Preferably around kelaniya, kiribathgoda, kadawatha areas in general. 

If it's a real professional i don't mind going the extra mile. 

Thanks in advance. 

[bpcd]

It`s looks like you have a rich mixture at idler, turn your idler/air screw clock wise to reduce fuel intakes at idler speed. hope this will help you.  

[Twin Turbo]

Try replacing everything you were asked to clean.

and checking the dwell on the c/b points,..

 

TT.

p.s, The  idle mixture leans when you tighten (turn right) the mixture screw.

Edited December 26, 2017 by Twin Turbo

[Rumesh88]

At the ECO test they take readings at both idle and 2500 RPM. Which one of this is failing? Or is it both? 

Only adjustment of the Air Fuel (A/F) ratio that can be in this type of carb is that of the idle mixture as others have pointed out above. Provided the rest of the things like spark plugs, air cleaner, PCV valve,idle adjustment are OK, the  A/F ratio during cruising speeds mainly depends of the size of the main jet (which is fixed of course) and cleanliness of the emulsifying tubes (There are two of them but let's concentrate on the primary one). Emulsifying tubes can be cleaned easily by spraying an liberal amount of carb cleaner through it top air bleeder opening. Get someone to do it first. Usually you do not need to open up the carb.

Edited December 27, 2017 by Rumesh88