Diagnostic warning light.....diagnostic done at kia dealer... no obvious but told it might be mixture problem as they had seen same before. Any ideas?
Mixture problems can be caused by a number of factors and faults. A computer module, the PCM, determines the mixture using data from different sensors. Re-circulated gas is also used to determine the mixture.
If the problem only happened at cold, then check the MAF (mass air flow) and (IAT intake air temperature) sensor, and also have the vacuum system tested for leaks, hat can affect the mixture and make a difference, particularly when idling.
If the problem reported by the error code was mixture related, then a common cause is often the EGR valve, that regulates gas re-circulation.
In this case the engine will be running rough at idle and when driving.
More problems that can return mixture related codes can concern:
Fuel injector problems (voltage , leaking injector, dirty injector). In that case more codes may be returned.
Excessive or insufficient fuel pressure due to fuel lines, pump problem, or bad fuel pressure regulator.
Gas recovery system, vacuum leaks and EGR valve.
Air leaks from air intake mainfold (after sensor), or defective MAF, IAT. If sensors are faulty, then you will get more codes.
If the car recently runt out of fuel, or if the fuel cap is defective you can also get an error related to mixture.
Exhaust leaks before reaching the O2 sensors.
If the only problem was a mixture related problem, then wait to see if the code comes back. The engine warning light will turn on. In that case check for additional codes and report the code here.
Things are different if there are more codes. Also there are differences if the mixture is too rich or poor.
Feb 04, 2010 |
2004 Kia Rio