Black smoke when warming up the car

[Creative]

Hi there, my engine 4g92p have some problem recently, when the engine is cold, i start the car and the engine start to vibrate and black smoke comes out from the exhaust, after 30 seconds or 1 minute the engine back to normal and no more smoke, but then sometimes while driving at lower rpm it jerks abit, if i stop the engine and start again when the engine is warm it starts fine, i've sent to few mechanics and they also having hard time to find the problem, i've changed spark plug, tried to change the spark plug cable and distributor, changed the fuel injector and the problem still there, hope someone can help me thank you.

 

[xtremeleo]

either the cold start valve is out, or its need to be retuned sir

---------- Post added at 07:30 PM ---------- 6 hour anti-bump limit - Previous post was at 07:28 PM ----------

ohh, and is the thermostat still in? how is it?

 

[Creative]

i guess the thermostat is still in there. guess it is fine, just that when i start .. it feels like 1 spark plug not working..

 

[xtremeleo]

please check dat and report back sir..

although i dont think so, as the engine performs well when it has warmed up

 

[Creative]

It performs well but it still consume alot of petrol

 

[xtremeleo]

hmm, does it warms up fast tak in the morning? we may be looking at multiple problems ni..

 

[Creative]

yeah it does warm up fast.. temp will go to normal in about 2 minutes

 

[huakenny]

plz diagnose it wit diagnostic tool.....maybe o2 is gone

 

[^pomen_GTR^]

check tps position at throttle body?over adjusted maybe?

 

[Creative]

ok i've checked it with the tool.. it shows airflow sensor and throttle body problem.

 

[huakenny]

ok i've checked it with the tool.. it shows airflow sensor and throttle body problem.

airflow will caused the problem....change/cleanthis 1st n diagnose again....

 

[D7zul]

black smoke = too much petrol..

u need more air..

change/clean ur air filter..

 

[Creative]

D7zul, airfilter is new, just replaced recently :)

 

[^pomen_GTR^]

how about your MAF???

visual inspection???look clean or blackie dirty???

 

[Creative]

The errors are

12. VAF CIRCUIT
55. IAC VALVE POSITION SENSOR
25. BARO CIRCUIT

So most probably my MAF gone? do i need to change it or can just service it?