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How to test for bad PCV?

edwardnese

Passed Driver's Ed
Hey guys i did some research and there seems to be multiple ways to test a bad PCV but i am still confused as to what signs to look for. So far i tested by:

  1. Start engine leave it idling, remove engine oil cap, engine starts sputtering and vibrating pretty hard.

Does this mean that my PCV is still good?
 

GroceryGTIer

Drag Racing Champion
No one really has a clear cut answer on this imo. It's supposed to throw a code for multiple misfires... mine didn't, however, it is possible that the pcv is unable to handle elevated boost levels and not be "bad". IE. I had read a forum where a company tested several own pcv's (few years old now) and every one of them failed above 17 psi. Under normal boost conditions, I think it would be less of a problem.

I also just took mine off to check the diaphragm, which I found to no longer be just a thin piece of rubber, it was beefier, sort of looked like a piece of fiberglass or something? Perhaps bad example, but it looked woven.

Which version do you have?
 

edwardnese

Passed Driver's Ed
No one really has a clear cut answer on this imo. It's supposed to throw a code for multiple misfires... mine didn't, however, it is possible that the pcv is unable to handle elevated boost levels and not be "bad". IE. I had read a forum where a company tested several own pcv's (few years old now) and every one of them failed above 17 psi. Under normal boost conditions, I think it would be less of a problem.

I also just took mine off to check the diaphragm, which I found to no longer be just a thin piece of rubber, it was beefier, sort of looked like a piece of fiberglass or something? Perhaps bad example, but it looked woven.

Which version do you have?


I will check which version i have when later but the diaphragm you're talking about is the orange looking thing?



or is it the circular disc shape area

 

BudgetPhoenix

Autocross Champion
Ive had a couple issues with my PCV. One time I had no symptoms except p0507 and slight surging idle. Pulling dipstick and oil cap caused it to run rough. The other time the diagraphm under the cap tore causingbig vacuum leak causing engine to shake violently and misfire on evey cylinder. There was so much vacuum it was very difficult to remove oil cap when car was running and you could feel lots of air being sucked through the breather hole on the side of the diagraphm cap.
 

GroceryGTIer

Drag Racing Champion
Ive had a couple issues with my PCV. One time I had no symptoms except p0507 and slight surging idle. Pulling dipstick and oil cap caused it to run rough. The other time the diagraphm under the cap tore causingbig vacuum leak causing engine to shake violently and misfire on evey cylinder. There was so much vacuum it was very difficult to remove oil cap when car was running and you could feel lots of air being sucked through the breather hole on the side of the diagraphm cap.

They are junk
 

bart2278

Go Kart Champion
I just want to jack this thread a bit, is it possible to throw an africa plate without the catch can to fix this problem?
 

corydd

Go Kart Champion
Whatever you do, don't get a cheap Chinese knockoff replacement PCV. If you replace it, go OEM.
 

QuitersLOSE14

Ready to race!
It's not the same, loose science of shaking and rattling. You can still do that. Watch this video though and you'll get some good "modern tech service" advice that actually applies to newer cars.

https://youtu.be/z9IG9GwKDrc

There's a company that makes adjustable ones, but they're primarily for V8's and would need special adapters for some cars. I think that company is M-E Wagner.


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QuitersLOSE14

Ready to race!
Honestly I'd cut it out and purchase a catch can though. You'll get true protection that way and easier and more reliable service intervals.


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