5.0l vacuum lines high idle ?

[pajeep]

Engine was running rough and rich. Solved by connecting fuel regulator & MAP to tree, w/ brake to large intke vacuum line. These connections were in the rear side of the intake.front side of intake 1 copper line for Trans (c6 auto trans) and other vacuum line (large) leads to rear of engine block. This cured the very rich condition but the idle is high. Idle screw is backed down all the way. What can I do to cure this?

 

[DirtDonk]

Is the line going to the rear of the block/manifold hooked up to a proper PCV valve by any chance? Just checking, because if there is no valve then you would have a pretty serious vacuum leak that would lead to wierd idling issues.

Other than that, I'm not sure. There is an Idle Air Bypass or Idle Control Valve, or whatever it's called, that's designed to help regulate the proper flow during idle, when the throttle valve is closed. Don't know how to check it in your case though.
Hopefully someone has run into this before and can help.

Good luck.

paul

 

[scsm76]

The Idle Air Bypass (IAB) could be bad, try disconnecting the power lead to it and see how much your idle changes. Also check for any vaccum leaks.
You are running speed density and not MAF right? If not you need to disconnect the MAP sensor from the vaccum and leave it open to outside air (becomes a BAP sensor.)

 

[pajeep]

no pcv valve

there is no valve I will install one, then go to the AIB valve. It's really running shitty now, breaking up alot. I will keep you posted. Thanks for your help.

 

[ransil]

vacuum leak will cause high idle and running crappy.