87 GMC Sierra R3500 7.4L TBI vacuum diagram

[DieselSJ]

Originally Posted by Captain J

Excellent, thank you very much
The AIR system is removed,
there is a 2ed PCV on the second valve cover do you know where the hose go to?
Additionally there is a valve behind the TBI (F port) from the manifold sticking out with its port capped, do you know where if it should be capped or what

PCV valve is in passenger side valve cover. Driver side valve cover should go to base of air cleaner to provide fresh air for PCV - it is just an open connection with no valve. Unless the previous owner of mine reversed it... Basically one side with PCV should go to vacuum source, and other side is fresh air supply.

Fitting sticking up out of the manifold behind TBI provides vacuum to A/C controls and modulator on automatic transmission.