Potential vacume leak on 3EFI

[BILWFURIOSIL]

I have read a lot of threads about idle problems on here with most knocking themselves out trying to correct it. This "find" may be stupid and common knowledge to all 62 owners but here goes anyway.

Today while my motor was idling, I decided to inspect the valve train for sludge through my oil filler cap. Once removed, the idle went to sh?t. Since this is a closed pcv system, apparently the oil cover removal allows unmetered air into the intake through the crancase ventilation and causes the idle to go away. Maybe if you guys cant locate your source of a vaccum leak, you can add checking the oil cap to your list for trouble shooting.

As I said, I just may be stupid but I figured I would post anyway.

Bill

 

[lowtideride]

Removing the the filler cap should not do anything at all. If you have not done so so far now would be a good time to replace all those vaccum hoses..

 

[dd113]

Good post
A well sealed 3FE will stumble or even die with the oil filler cap removed. Good thing to do is to replace the oil cap gasket to ensure a good seal.

It makes no difference on a 2F; Carb vs EFI

 

[bigbertha]

hmm

uhh... is Lowtide right?? or is DD??? LOL. Two adamant opposite answers...scary.

 

[euclid]

Lowtide ain't got no 3FE. DD's as right as he is ugly. Good post, Bill.

 

[lowtideride]

My buddy ran his 2f with no oil cap for while for no ill effects, nother cruiser head did not even notice a difference that the hose the runs from the valve cover to the air cleaner assembly was off. My rig also runs at a steady idle with the valve cover completly off. As for the 3fe ya got me there, its ssitting on the back of my house needing work. This sounded like a muffler bearing thread at first to me but i have not run a 3fe for a long time....just a 2f.

 

[BILWFURIOSIL]

Thanks for the responses

Thanks guys for the positive responses. I didnt want to feel like a dummy posting here.

Lowtide, the reason the 2F will run is that it does not have a computer that monitors air flow and makes adjustments to all aspects by the amount of air flowing over the throttle body. Once you introduce unmetered air, ( air after the air flow meter) it acts as a vaccum leak because the computer has no idea of the additional air flow and does not compensate for it.

This forum is great
Bill