Need help with 1990 L98 vacuum line schematic...
Thread Starter
Heel & Toe
Joined: Apr 2026
Posts: 18
Likes: 5
From: Appleton, WI
Need help with 1990 L98 vacuum line schematic...
So I've been tearing into my 90' vette. Replaced intake manifold gaskets, egr valve, IAC, PCV, MAT, and fuel pressure regulator (pics to come this weekend). However, upon disassembly, half the vacuum lines broke because they're so brittle, and I plan on replacing all of the hard lines with rubber ones. I have a FSM, but it doesn't have any of the schematics for the vacuum lines. I apologize if this has been asked before, but I can't seem to find the full schematics anywhere. Had to order a new hvac check valve as one of the stems had busted off. Off of the large vacuum "bulb" in the front, there is a line that connects to a "Y" behind the driver wheel well. One goes to the cruise control, the other line (which is a bit lengthy) is just dangling there. So now I'm lost. Thank you in advance for the help.
Edit: there's also a "Y" fitting on the front of the lower intake - one line goes to the EGR solenoid, the other one looks like it goes towards the firewall, but it's missing. So I have no idea where it's supposed to go.
Edit: there's also a "Y" fitting on the front of the lower intake - one line goes to the EGR solenoid, the other one looks like it goes towards the firewall, but it's missing. So I have no idea where it's supposed to go.
Last edited by Stevo1975; Apr 30, 2026 at 06:19 PM.
Thread Starter
Heel & Toe
Joined: Apr 2026
Posts: 18
Likes: 5
From: Appleton, WI
Already checked - it's not there. In fact, the sticker for the belt routing isn't anywhere to be found. But at least I figured it out - eventually.
