Exhaust burning/ Emission

[X2oo5]

So ive never had a car thats done this before and im not sure if its because of the emission law or whatever..

but i removed my oil cap when the vehicle is running and exhaust is coming out of where the oil fill cap is... soo im wondering is this vehicle like a double burning of exhaust fumes or something to keep down emission and aswell.

My gas mileage has drop from average of 745kms to about 494kms/ tank, what could be causing this

thanks.

 

[finch13]

Steam will come out of the fill cap when the engines hot, if you saw the "exhaust". If you felt it, you're probably feeling gases that travel through the PCV system.

The only possible way for actual exhaust gases to get from the combustion chamber to the fill hole would be to get past the valve guides, which is only theoretically possible on the compression stroke when all valves are closed.

 

[HondaLuver83]

Make a video and we will tell you if your blow by is excessive or normal. Any aging engine will have some blowby, some are more than others.

Or you might have a PCV valve coming from your valve cover to your intake manifold that needs to be changed. That can cause low gas miles and will cause your car to run poorly.

It also be wat finch said, bad valve guides as well.

 

[finch13]

Actual piston blow by would be seen in a compression test.

The crap coming out of the PCV hole or fresh air hole in the valve cover is pressure getting relieved from the crankcase from the pistons moving down.

 

[X2oo5]

Well I can try to get a video tommarow hopefully... I was thinking the PCV or EGR starting to plug up..

 

[finch13]

Change the PCV valve? It's a $4 part.

 

[rvangj]

Actual piston blow by would be seen in a compression test.

A leak down test is a better way of testing blowby.

The crap coming out of the PCV hole or fresh air hole in the valve cover is pressure getting relieved from the crankcase from the pistons moving down.

The pcv opens at ide to allow exhaust "blowby" in crankcase back to manifold for emissions control. Nothing to do with the small amount of pressure from down movement of pistons.

 

[finch13]

The pcv opens at ide to allow exhaust "blowby" in crankcase back to manifold for emissions control. Nothing to do with the small amount of pressure from down movement of pistons.

The PCV is working whenever the engine is running, not just at idle (when the lowest amount of blow-by is generated). Blow-by happens on the compression stroke, not exhaust stroke. Take the PCV valve off your car while it's running and feel the amount of gasses flowing out... do you think that high of a volume is all blow-by? You would have very low compression with that amount of blow by.

The fact is, the pistons moving up and down will create positive and negative pressures inside the crankcase, which the PCV valve helps keep at neutral level ALONG with venting blow-by gasses.

Here, read about it: http://autoshop101.com/forms/h63.pdf