Stock Vacuum Line Routing
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Teching In
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Stock Vacuum Line Routing I have spent a couple of hours on Google and searched this site but have not found what I am looking for. Just to let you know I did use the Search function. I have a 2002 Firebird Formula with an LS1 and I recently removed the intake to replace the oil pressure sensor. In the process one of the plastic vacuum lines broke and I can't find the opposite end of it so I can replace it. I know there are 3 vacuum connections on the rear of the intake - one for the power brake booster, one that goes to the air diaphragm thingy that is attached near the driver side fuel rail, and then then is another vacuum connection that the line goes off somewhere on the passenger side of the engine compartment. From what I have read, I believe this goes to the HVAC system. So, about 5 inches of the vacuum line is still connected to the back of the intake but it broke off and I have searched near the firewall and on the passenger side and I can't find where that line goes. Does this go through the firewall somewhere? I need to replace the line. Please tell me where this line goes. Thanks in advance.
BTW, all the diagrams I found online or videos on YouTube show the connections on the back of the intake but none of them show me where that line goes on the other end.
BTW, all the diagrams I found online or videos on YouTube show the connections on the back of the intake but none of them show me where that line goes on the other end.
You should find a small vacuum junction connector toward the back near the A/C pipes, one line from there is for HVAC, the other I'm not sure about, the line from the intake hooks to that.
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Thank you. I finally found what I was looking for yesterday. The hard plastic line had broken when I removed the intake but I could not find the opposite end so I could replace the entire vacuum line. Yesterday, after feeling around I felt a hard plastic nub right near the firewall, on the passenger side. It was the vacuum line where it had broken and it is wrapped in the large wire loom that runs on the passenger side next to the intake. So I will be able to connect a rubber vacuum hose to that and then to the back of the intake so I should be good. I still couldn't find where the hose ends up but now it doesn't matter and I don't want to have to take the flex tubing off the wire loom and trace the vacuum line to its origin.
All should be good now. Thanks!
All should be good now. Thanks!
when you turn the **** on your HVAC control to decide where you want the air to go, your feet, the windshield etc, the HVAC doors open and close to accomplish this, but they run off of vacuum pressure to do this. they get this vacuum from the intake. the reason you cant find the other end of the broken piece, is because this hose disappears and runs inside the big wire loom that runs to the ECU connectors.
so once it goes inside the loom, it runs toward the ECU and comes out around the AC box and comes to a T. one end of the T disappears inside the firewall/ac box, and the other end runs along the top of the passenger side fender to the canister that i assume stores the vacuum so that its built up when you want to use your controls, i guess similar to how the power brake booster works. running this line back inside the loom will be a pains, so the easiest way to repair this would be to go get 5 feet of 9/32 vacuum/emissions hose from advance, and go over to the T fitting. find the end that runs to the intake, and pop that boot off, but its goona be really tough so twist it as u pull to get it off......then once you get it off, pull it out of the wire loom, and cut the plastic tubing, but keep like 6 inches attached to the boot end so the boot can be reinstalled. now slide your 2 plastic tubes into each end of the 9/32 line and reinstall into the intake and the T. i dont think its necessary to clamp. seems decently snug and i dont think a ton of pressure flows through this.
so once it goes inside the loom, it runs toward the ECU and comes out around the AC box and comes to a T. one end of the T disappears inside the firewall/ac box, and the other end runs along the top of the passenger side fender to the canister that i assume stores the vacuum so that its built up when you want to use your controls, i guess similar to how the power brake booster works. running this line back inside the loom will be a pains, so the easiest way to repair this would be to go get 5 feet of 9/32 vacuum/emissions hose from advance, and go over to the T fitting. find the end that runs to the intake, and pop that boot off, but its goona be really tough so twist it as u pull to get it off......then once you get it off, pull it out of the wire loom, and cut the plastic tubing, but keep like 6 inches attached to the boot end so the boot can be reinstalled. now slide your 2 plastic tubes into each end of the 9/32 line and reinstall into the intake and the T. i dont think its necessary to clamp. seems decently snug and i dont think a ton of pressure flows through this.
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Thanks Floorman. I never could find the T connection at the AC box and thought I would have to start tearing all apart today but as I wrote above, I found the plastic line in the wire loom. Woohoo!. I had replaced part of one of the other vacuum lines the last time I removed the intake, but this is the line that goes to the driver side to the air diaphragm thing (not sure what it is Called). That line has a check valve in it. I did exactly what you proposed - I put a 9/32 rubber line on the T connector at the back of the intake and on the air diaphragm and then took the check valve, with a little bit of hard line still attached to each end and plugged each of those ends into the 9/32 hose and it worked great. I plan to do the same with the hose in the wire loom. I will cut a piece of the 9/32 rubber hose and leave lots of slack so I can plug it into the back of the intake and then have plenty of hose so after I install the intake I can reach back and slide the other end of the 9/32 rubber hose over the hard plastic line in the wire loom. What a pain!
Thanks for your help. I am new to General Motors stuff so this is a little frustrating.
Thanks for your help. I am new to General Motors stuff so this is a little frustrating.
