86 GL-10 turbo wagon. I picked it up a while ago and it had already been sitting at least a couple of years. Put some MMO in to free up the HLAs and checked the oil. Pulled into the driveway with the engine running (engine warmed up) and opened the oil cap to top it off, and the thing almost died. Curious, I put the cap back on, and the revs came right back up (750-800). I pulled the cap off again, and the same thing happened again. Anyone have a similar experience?

motor must be pretty worn out. do you have alot of blow by?

Weird vaccumm leak or blockage that causes the manifold to be pressurized?

I assume when you pull the cap, is there much air blowing and sucking through the filler neck?

Thats about as far as I go.. This thing is turbo, I shudder to think what else could be going on..... I'd try cleaning all vaccumm lines.

I'm sure some more knowledgeable folks will be of more help.

The turbo's are a closed system. Anytime you open a air passageway it will drop the idle.

check/replace the entire PCV system, from the valve on the back of the throttle body to all the hoses. I bet they're clogged full of crap.

 

I've the best place to get the PCV valve is at the dealer. I believe they call it an 'air control valve' or such (just make sure you get the right part, I got the 'T' part once by accident)

The turbo's are a closed system. Anytime you open a air passageway it will drop the idle.

 

+1!

The turbo's are a closed system. Anytime you open a air passageway it will drop the idle.

 

+2

 

This should be true of any engine with a closed PCV system, if you open the cap and the idle doesn't change that means the air was already getting in somewhere else or the rings are so bad they are alowing a lot of air by at idle... not good.

 

Gary

this is normal....worry when the rpm wont change....my 2$ worth

Thanks. You've put my mind at ease. I'll take it out and thrash it a little tomorrow and see how it behaves.

My turbo cars would do the same thing... my EA81 carby's never have.