NMDesertRat

1986 4runner, 22re.

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.

thanks in advance!

92ehatch

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.

NMDesertRat

Sounds about right. The a/c idle up is definitely on the front. Where should it plug into? Ideas?

Co_94_PU

iTrader: (-1)

These are color coded and have part numbers on them. Get it clean and snap another photo.

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maco35

Just follow the red and green vacuum lines on the fuel pressure regulator VSV blue connector.

NMDesertRat

Omg. That schematic is the best thing ever. Thanks so much for that!

As for cleaning, that's happening when I adjust the valves next week.

RAD4Runner

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:

Manually Opening Fuel Pressure Regulator Vacuum Line to Atmosphere.

Fuel Pressure Gage Piggybacked On CSI Mod is very handy. Someday I'd like to upgrade to an electric sender to read-out on dash.