Need help identifying the function of these VSV's
 

Hello everyone.

Does anyone know what function these valves (Red and Blue) serve?

https://imgur.com/a/ooCKaQT

They are located on the passenger side wall of the engine compartment (1992 Pickup 3vze), right behind the fuse box. I thought that they were part of the EGR system, but despite being connected via vacuum line to the other valves of the EGR system, they aren't listed on any diagram of the EGR system.

Any help is appreciated, thanks!

ADD (automatic differential disconnect). http://web.archive.org/web/201204242...26addcontr.pdf

Your's is plumbed slightly different than mine, but should work. The other end of the blue/white check valve should go directly to the "gas filter" (3 outlet fitting on plenum), possibly shared with cruise control.

These VSVs do NOT connect to anything in the EGR system.

Thanks, Scope!

Believe it or not, I was thinking about reaching out to you directly about an issue I've been dealing with. I've seen you as an active voice on EGR related threads and am chasing an issue with mine.

Not to be unnecessarily unfriendly, but most questions like that don't benefit from a PM. Just start a thread and post it here. If I don't know the answer, there are lots of people who do! (And if I DO know the answer, it might benefit other people if the answer is posted in the forum.)

Yeah, no worries. It's a good point.

Vsv
 

On my 91’ the red is fuel pressure regulator valve green is EGR and blue was pair! I did full EGR/pair delete and hard line delete so I only use the Red now!