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I have been having start issues in the mornings. I need to start with a bit of gas pedal and hold it for as or 30-45 secs or it dies on me. once warm it runs fine. I thought, maybe it's a vacuum issue. I started digging around and found this possible cab. It's harnessed and missing one line and the other is disconnected. I have deleted vsvs, but I'm pretty sure this is not one of them, otherwise I wouldn't have left it plugged into the harness.
What is this and more importantly, where the heck does it plug into? I can't find any blanks.
I believe that one is the fpu vsv. Basically raises the fuel pressure for warm starts . It could be the ac idle up vsv but that one is normally mounted further towards the front of the valve cover.
Thanks for the diagram, maco35.
Yes, Fuel Pressure UP vacuum Switching Valve (VSV)
Here's a picture.
At normal operating temp, VSV connects FP regulator to vacuum line from intake manifold. FP sees manifold vacuum and that sets fuel pressure.
For warm starts (to prevent vapor lock?), the VSV blocks off vacuum line to intake manifold, and opens vacuum line to pressure regulator to atmospheric pressure, raising fuel pressure.
In video below, engine's at normal operating temp. I unplug the vacuum line to FPR to expose it to atmospheric pressure. Watch the fuel pressure gage reading: