Have Subaru Questions? Ask a Subaru Mechanic and Get Answers ASAP
Thank you for your question!My name is ***** ***** give me a moment to review your question and respond with the assistance you need!
50 psi on a cylinder would explain a misfire, but only on that cylinder. It shouldn't affect all of the cylinders. With compression that low it's either a stuck valve. bent valve or broken compression ring on the piston.
It's an odd issue you are having, I think I would next check the fuel pressure, since it's affecting all the cylinders, however if you only have 50 psi on one of the cylinders, you have a bigger issue to contend with first to try and find out why.
Sometimes you can put some oil in the cylinder and retest compression. I know its a pain on this engine, but if the compression comes up with the oil, then the rings are the problem, if not, then it's a valve issue.
Ok, I'm sorry, I didn't realize that.
All 4 like that is almost always timing, The only other thing I can think of would be worn out cams causing that or catastrophic failure of the belt which we know didn't happen. I suppose all the rings could have gone bad, but I have never heard of that. Surprised it will even run with compression that low. I think the min on this engine is about 120 psi
Please let me know if there is anything else I can do to help.Also, please remember to rate my answer.Thanks so much!
Technically it shouldn't be affecting the compression. Because all the valves should close to build the compression and the engine isn't running when you check it.
I think the same for the vacuum hose, but, if there is a vacuum leak when it's running perhaps that's causing the misfires on all cylinders.
With it running spray some carb cleaner along the intake and the turbo and see if the idle smooths out. If it does, then you have a vacuum leak. It could also speed up.
Not saying you did the compression test wrong, but perhaps the tester has a problem. To get the exact same compression on each cylinder is pretty unheard of
Seems like the next best step, but I am puzzled by that compression my friend.