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High Crankcase Pressure

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2 years 5 months ago - 2 years 5 months ago #52145 by crossmf
2005 Mitsubishi Galant 2.4l 210000 miles.

I changed my timing belt and suspension parts when I had time to let my car sit. Well when I had the old belt off I was waiting on parts I decided to check vavle lash. When doing so I rotated my cam sprocket. Guess what? I bent the vavles. I found a used head at my local salvage yard it looked good valves look good ect. I know you need to have the head machined but I didn't.

New head gasket timing belt water pump. I put it back together and I have HIGH CRANKCASE PRESSURE. I have good compression across all cylinders 180 to 180 psi. I do have a p0421 and now a p0431 cat codes. The 421 been on for about 1 year. I have positive fule trims @ idle of about 12 car use to have maybe 2 at most before this. The fuel trims improve @ HWY speed. Car seems to sputter and shake while in drive especially when the ac is on at stops.
 Point me in the right direction. Thanks in advance. O yea spark plugs are new. And new PCV 
Last edit: 2 years 5 months ago by crossmf.

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2 years 5 months ago #52148 by Tyler
Replied by Tyler on topic High Crankcase Pressure
How high is the crankcase pressure, specifically?

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2 years 5 months ago #52150 by crossmf
Replied by crossmf on topic High Crankcase Pressure
Idk not really sure where to measure it. I guess I could put a gauge on my oil dip stick or my pcv? Hard enough to blow air about 3 or 4 inches out when the oil cap is off with my hand over it. And it sounds like a humming sound idk how to explain it.

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2 years 5 months ago #52161 by ksat22
Replied by ksat22 on topic High Crankcase Pressure
Excessive blow-maybe caused perhaps by a bad PCV valve or stuck/worn compression rings on piston(s)?

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2 years 5 months ago #52163 by crossmf
Replied by crossmf on topic High Crankcase Pressure
I have a new pcv on. And compression is all good every cylinder is reading 180 to 185 psi.

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2 years 5 months ago #52175 by crossmf
Replied by crossmf on topic High Crankcase Pressure
Can a restricted exhaust cause this?

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2 years 5 months ago #52184 by crossmf
Replied by crossmf on topic High Crankcase Pressure
I belive I found my rough idle low battery voltage @ idle 12.5 volts at best and it dips down to 11.7. Now for the blow by it still puzzles me. The car never had it before the head problem. Do yall think a restricted or even partial restricted exhaust can cause this?

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2 years 5 months ago #52209 by ksat22
Replied by ksat22 on topic High Crankcase Pressure
A leak-down test might be a better way to determine what shape the rings are in.

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2 years 5 months ago #52225 by Tyler
Replied by Tyler on topic High Crankcase Pressure

Idk not really sure where to measure it. I guess I could put a gauge on my oil dip stick or my pcv? Hard enough to blow air about 3 or 4 inches out when the oil cap is off with my hand over it. And it sounds like a humming sound idk how to explain it.
Don't worry, I know what you're talking about.

You can definitely use your vacuum gauge on the dipstick to measure crankcase pressure. A manometer would be better? But the vacuum gauge will show you obvious PCV problems. Restricted fresh air hoses, stuck PCV valves, like that. I know your PCV valve is new, but that doesn't mean it's good.

But, to be honest, it sounds like you have an appropriate amount of blowby for an engine with 210,000 miles that's just had a head put on.   It's possible that an exhaust restriction could cause that? But I tend to think it's just a function of age and internal engine repairs.

The charging voltage could definitely be part of the problem. What's the voltage drop across the alternator B+ and the alternator case?

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2 years 5 months ago #52228 by AJeep18
Replied by AJeep18 on topic High Crankcase Pressure
If you think that is bad just wait till you see the crankcase pressure on a 6.4 power stroke with 210,000 miles 

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2 years 5 months ago #52249 by Andy.MacFadyen
While 185psi is a good compressioin test compression pressure test results can be misleading. Smaller sized engines are more prone to cutting out at junctions  when high electrical loads are on if  the AC is on or the power steering is turned  if the throttlebody or IACV valve is carboned up.

" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)



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