Engine Issue

[aknight_sa]

Good day guys,

we ahve been having some strange issue with my wifes car, its a 2008 Kia Optima 6 Cylinder. the issue is for no reason the car’s engine just dies off. when we crank it it doesnt start.

this happened three times over a period of 2 years, the first time it happened i was trying to figure out the reason so i was checking the fuel lines, spark plug connectors and all was fine. but when i removed the intake Air filter cranked the engine.. and it worked with no problem at all.. put everything back together and it was like nothing happened..

second time it happened i pulled my scan tool to see if the cars computer caught anything.. and there were no codes at all.. so i just removed the air filter and it worked normally..

after the third time which was yesterday i took it to the Kia service center.. and they started throwing causing for the issue at the cars computer, or at one of the sensors (MAF or IAT).. the car will be taken in there the coming Wednesday.

as it seems that for some reason the air filter stopped the air from going into the engine…

Topic

[Grayfox]

The air filter is not the issue, their may be a blockage down the air line and when the airfilter is on it restricts airflow just enough to stall the engine.

Could be one of the sensors that controls air flow

[aknight_sa]

if the MAF is bad it will give a rough unstable idle, which didnt happen.. the IAT wont stall the engine

also, there are no sensor around the air intake filter/box…

i will take air intake kit apart as i do agree that there must be something inside that’s blocking air flow

[Grayfox]

I am no mechanic and i have very little exp with this sort of thing so i am thinking logicly.

[380]

what kind of filter is it stock, basic, performance, etc and how old is it? Have you confirmed that a clogged filter is not the problem? more specifically how old was the filter at the time of these events? since its only happed 3 times over the last 2 years im thinking that maybe the filter is starting to get clogged causing low air flow and as a result it dies you then eventually change the filter based on your maintenance schedule and then don’t have any problems for awhile until the filter starts to get clogged again. just a thought

One last question at the times this happens were you in park idling, coming to stop, or accelerating. If you were accelerating then i would go with filter or air system being clogged. because with sudden acceleration the engine’s demand for air would suddenly increase and if a blockage of some sort was restricting the airflow then the engine wouldn’t be able to meet demand for air and die.

[aknight_sa]

Quoted From 380gb:

what kind of filter is it stock, basic, performance, etc and how old is it? Have you confirmed that a clogged filter is not the problem? more specifically how old was the filter at the time of these events? since its only happed 3 times over the last 2 years im thinking that maybe the filter is starting to get clogged causing low air flow and as a result it dies you then eventually change the filter based on your maintenance schedule and then don’t have any problems for awhile until the filter starts to get clogged again. just a thought

One last question at the times this happens were you in park idling, coming to stop, or accelerating. If you were accelerating then i would go with filter or air system being clogged. because with sudden acceleration the engine’s demand for air would suddenly increase and if a blockage of some sort was restricting the airflow then the engine wouldn’t be able to meet demand for air and die.

for your first question, the first time it happened was one week after the car was serviced and had a new filter installed..

second was almost a year later.. not sure if it was the same filter or not..

third time was with a 4 month old filter..

for the second question, it happened all three times while the car was running, twice on the highway and once near my house (accelerating)

[aknight_sa]

yes, and it was is a stock filter

[BigC]

Hi aknight_sa,

I would double check the connections at the battery. I believe the battery is in very close proximity to the air filter. Just want to make sure that in removing the air filter, the jiggling involved does not affect the connections at the battery.

The MAF sensor is located in the air duct between the air filter and the throttle body. It should be easy enough to remove for inspection. Some MAF sensors also have an air temperature thermistor as well. This thermistor can get coated with pollen and debris, causing an inaccurate air temperature reading. If your scan tool displays live data, it would be good to see what this thermistor is registering during start up and while in operation.

Were any particular events occurring when the vehicle just died? (raining outside, went over a bump, went through a large puddle of water, etc)? Keep us posted.

[aknight_sa]

i will check the battery connections and clean them if they do need cleaning, but i dought this is the issue as the engine cranks normally when the issue happens and there is no sign of a bad battery..

nothing was happening when the engine stalled, no rain, no bump, nothing!

[dreamer2355]

Next time the engine stalls, i would be checking for fuel and spark and see which one is missing. That will hopefully start you on the right diagnostic track.

When you removed the plastic intake, did you disconnect the MAF too to in aid restarting the vehicle?

[EricTheCarGuy]

Something that I think has been overlooked is any air leaks in the tube from the air filter housing to the engine and given that every time you moved it it seems to work I think it’s worth looking into. ANY leaks you find after the sensor or before the engine can cause performance problems or stalling.

[Author]

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