Compression loss after injector change???


Jo Bu needs a refill!
Feb 14, 2002
Dealing with a 92 Typhoon with roughly 97k miles, appears stock with a dead miss determined to be in #5 ylinder. Compression test showed all cylinders ranging from 155-170 psi...So, after replacing #5 injector engine still has the same miss....and now compression only shows about 50 psi on #5. How is this even possible and what are we overlooking?
You should probably post this over on where everyone can see it and help you becuase I can't think of any reasons why an injector change would kill cylinder readings
I do not see how that is possible. Swap back in the original and retest. Are you running the engine after each cylinder? If you run the engine after each test then it possible that fuel is pooling in the cylinder and the greatly affects compression readings. Alternatively you can disable ALL fuel injectors to prevent them from affecting the reading.
Put compressed air in the cylinder and observe the leakage. That will definitely show leakage somewhere. Probably past a valve.
I would bet that it's a broken ring land or ruined piston!!!! Could get lucky and just have to replace that???