I have black smoke coming out of my Volvo 940...i have changed the air mass flow..the air filter....the coolant temp sensor and the control box...it idled well for about 15mins then it went back to the same black smoke problem....could it be wiring

Year,make, and model. Which temp sensor you looking for coolant or air?

ok lets start with the codes they say your getting. P??? which 1's and how many. there are few o2 sensors, are they next to the Exhaust next to the converter? MASS AIR FLOW -MAF use this, for now i am guessing, until i see the correct codes your are getting. this could be the 1 you may have below, please read it........

• P0103
  Mass Air Flow Sensor Circuit High Input
• Possible causes
• Faulty mass air flow sensor
  - Intake air leaks
  - Dirty mass air flow sensor
  - Dirty mass air filter
  - Mass air flow sensor harness is open or shorted
  - Mass air flow sensor circuit poor electrical connection
• Before replacing the mass air flow sensor, try replacing the air filter and cleaning the air flow sensor with low compress air or mass air flow sensor cleaner. Reset code and drive vehicle. If the code comes back, it may be necessary to replaced the mass air flow sensor.
• possible symptoms Engine Light ON (or Service Engine Soon Warning Light)
  - Engine stall
  - Engine running rough
  - Excessive fuel consumption
  - Excessive smoke
• the code is generated when An excessively high voltage from the sensor is sent to Engine Control Module (ECM).

2003 NISSAN Altima Sedan OBDII Codes List

Keep in mind the fuel strategy of the fuel injector is what the call PWM(pulse width modulated) so low fuel pressure can cause rich black smoke.coolant temperature sensor that is reading under temperature can cause black smoke and so can the MAF (mass air flow sensor) use carburator cleaner or brake cleaner and clean MAF outside of the vehicle and see if that helps

P0103 - Mass or volume air flow circuit high input.

Symptoms: Engine stalls, running rough, excessive fuel consumption, excessive smoke from the tail pipe, check engine light on.

Possible Causes: Dirty mass air flow sensor, dirty mass air filter, mass air flow sensor harness is open or shorted, mass air flow sensor electrical circuit poor connection, intake air leaks, faulty mass air flow sensor.

P0116 - Engine coolant temperature circuit range/performance.

Symptoms: Check engine light on.

Possible Causes: Low engine coolant level, ECT sensor harness open or shorted, ECT electrical circuit poor connection, faulty engine coolant temperature sensor (ECT), faulty engine coolant thermostat.

Black smoke points to unburnt fuel. I would start by replacing the spark plugs and wires if you have not done so in the last couple of years.

I had a 1995 nissan pick up with a similar problem, may want to try cleaning out or replacing the EGR valve.

It does indeed sound lika an air flow sensor. I would actually try a salvage yard one, "because" these do not go bad as often as other components of this engine. However some yards will let you try one and return it if that isn't the problem. You should never spray any fluid containing petroleum disstalates, because they eventually will deteriate the hair anchors(wire supports) within the unit. This could also be an intermittenantly sticking injector.

Check the fuse to the injector. If it is out or got wet, it could mimic these conditions. let me know what happens. I have an 85 model.

Change the the O2 senor on the catalytic convert. Its probably dead.

Ok. Black smoke, mean fuel system too rich.
1 of the problem related come if the car is hard to start in the morning, If is the case, you need to check the coolant sensor and the harnes,
But if the car start normally in the morning or when the car is cool. You need to check for air leak in the intake.
check the hose from the air filter to the throthe bady for crack.
pinched. If evrything is OK. you need a MASS Air Flow Sensor.