when i remove my oil filler cap while the car is idleing is a lot of air supposed to get sucked in there? same thing with my oil dip stick. i dont remember ever hearing it before.
i do have a checkvalve and i am also running a catch can between pcv hose and intake. but no pcv valve.
anyway when i put my hand over the oil filler i feel a strong suction.

 

TTT

I don't know, but that certainly sounds like a problem, probably with the PCV system.
Maybe someone who knows will speak up.....

 

actually, yes, u should feel vacuum. thats the pcv system doing its job. a little strong, but yeah, you should feel a vacuum

 

I never noticed anything. Hmmm, maybe I'll go see.........

 

are you sure you have the right sized PCV valve? if its sucking enough for u to hear it clearly, that may be the problem. a too big PCV valve.

 

blkz28spt, its not going to suck your hand up like a carburetor would, it'll be slow, like 10-15 secs with your hand against the oil fill port, you'll feel a slight, slight vacuum.

 

i dont have a pcv valve, i have a check valve, (mcmaster-carr). if the check valve is bad would it to that,? or maybe the pcv system is not getting fresh air? but i can bearly take out the oil fill cap when the car is idleing.
wierd.
another thing i noticed the plug that i put in on the t.b. was gone.(where the pcv hose used to hook up, now its on the ati inlet hat) fixed that
still same problem.

 

I checked. It is a slight vacuum. Nothing I'd ever be able to hear (especially over the noise my car makes). It is there though.

 

thanks for checking man,
anybody else ever heard of this?

 

i forgot to mention i am reading 20hg of vac. at idle. is this too high?
anybody?

 

Samething here, I asked that same question ... in another thread
Mine is a 1998 Z... .. Noticed this when the car is idling.... at normal operating temperatures... and I open the oil cap .. The Car stumbles slightly ... You can hear a change in idle speed.


Then If I put my hand on the oil cap hole,
it creates a suction.. If I remove it it stops.... ( Changes in Idle Speed again)

Is this normal.. . Or Does this means BAD RINGS..??

My Brothers 99 Vette Does not do that.. I tried it on his..
( Had his car Idling ,then I proceeeded to take the oil cap off.
and his car did not stumble.)

Thanks

 

It's not normal, but I don't know why it does it. My Z28 doesn't, but my DD Mazda does and I've been wondering what causes it.

 

It should be able to hold a racquetball.

 

I legitimately fear putting my hand over the oil fill neck on my DD.

 

Lol! Why is that?

 

It sucks that hard, which I'd say some of the guys in this thread have that prob with their LS1s. Can you say instant hicky, or worse? lol

I watched the true duals video in your sig. How much water was in them pipes man It never stopped spitting!!!!!

 

I Tried it in my 05 silverado... It did not do it either..
Could not hear a change in idle speed. ,

on the Z .. It definitely changes the idle speed .. ( As soon as
you release your hand it goes back to normal.

It creates a suction too.. If you leave your hand long enought.

Anymore Help Appreciated..

 

That was a "dew-liscious" morning!

 

worried about the Vaccum It creates
when I put my hand in the oil cap.. and why it stumbles too..


BTW... My PCV is stock...

It tends to ilde at at about 1000-1100. ( Manual)

Someone...

Can you all check to see if you all's car does this while idling
at normal operating temps

Check to see if stumbles or creates a vaccum with the oil cap off.

 

We had the exact same problem eith my moms Buicj Park 3800 series 2. You take off the oil cap and the car idles erratic kinda and a lot of suction? In our case it was a small crack in the Intake manifold.