Big problem, I think

bestbiker

Member
:
2004 Mazda 6s Wagon
So I just cant leave stuff alone...

Ive been having problems for months with my engine sucking oil up through the PCV valve, mostly because its sitting in oil and goes directly into the intake so it has alot of vacuum pressure to it.

I thought to myself, If i reduce the vacuum pressure behind the throttle body it will make a big difference!

So I went to twist the idle adjustment bolt that controls what position the throttle/air flap is in when its 'closed' and as my luck would have, that bolt broke in half and out shot a spring and metal rod.

To compensate for that, I drilled a bit of a hole in the throttle plate, It might be just a bit too big because now it idles just below 1000rpm and when im driving the rpm will bounce from 1300-1600 only at that range if im coasting.

PROBLEM. I took everything apart to check the plugs and had gas, raw gas in the plastic manifold and down into the throttle body to the air filter.

HELP! I do know that there is a vacuum hose that goes from the intake manifold to the fuel rail, but I would assume it would suck up less now that the vacuum pressure is less inside the manifold..

3.0 liter v6 in a 2004 mazda 6s
 
Bump

Since the engine is a constant vacuum, how is it even possible for gas to go backwards up into the plastic intake and out the throttle body???????

Someone said one of the vacuum lines hooks up to the fuel rail on a pressure regulator. Does anyone know how that system might work?
 
Check 6crew.com (can I say that here?) or post this thread on that site. Most people here are Mazdaspeed6 owners whereas the opposite on the other site I mentioned. You might have better luck there. I haven't had any of the above experiences otherwise I'd be of more help. Believe it or not, their are alot of "homemade" mods that are reliable for the I4/V6 that don't apply to the Mazdaspeed6, so I can (sort of) see what you tried to do and why. Most people just replace the stock PCV valve as it's junk and gets stuck open.
 
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Thanks zoom. I have actually replaced the pvc 2 times and end up with the same problem because the top intake manifold has so much suction it almost leaves a bruise if you plug it with your finger.

The most logical explanation I have come across for that problem is the drain hole on top of the valves is clogged or something and is causing oil to pool up under the pcv valve.
 
I put a 2nd pcv valve inline with the oem one because they fail so often. In regards to your problem I would probably try and find a replacement bolt/spring/rod. I personally dont like drilling holes unless I am positive it is the solution. I agree with Zoom, I would post up on 6crew.com. There are some mazda 6 motorheads over there who are more willing to help then complain. This is honestly the first time I have ever check this section.
 
Thanks guys. I checked over there and got a prompt answer, most likely a ring problem because that would be the only thing to cause oil/gas to flow backwards at the intake point.

drilling the hole was a temporary solution so that I could at least drive home and get by for a few days until I got stuff figured out.
 

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