Vacuum hose mystery
 

Could someone please help me with a Grand National vacuum hose question? I have two vacuum hoses going to the passenger side fender, one is coming from the vacuum block for the boost gauge sensor, I was able figure that one out. I have another one that "tees" off of a vacuum line near the transmission dipstick and comes over to the passenger side fender as well, for the life of me, I can't figure out where it should go to. Where does that vacuum hose plug into? Please help, thank you!!

This may be helpful. Easy to find info, my problem is I keep forgetting it's at fingertips. http://ww2.justanswer.com/uploads/am...40601_vac1.jpg

Thank you Rich, it's a hose that "seems and feels" like it should go to the passenger side because it's contoured in the shape of the heater box, I feel it's for the HVAC. Is there a nipple on the passenger side that this would plug into, I look and look but don't seem to see any. Thanks again for your help.

Your welcome Chris, here's a photo that may show something Photobucket. Interesting, I believe the boost gauge is a vaccum gauge that is showing boost as vaccum just goes to nil when gas pedal is depressed fully. This would show full boost and be 0 vaccum condition, clever.

Would it be feasible that at wide open throttle with GN's the A/C shuts off for extra HP? A vaccum actuated switch would make sense for that then. Seems I read someplace of doing that years ago. Also shows something on hose routing diagram to this effect.

Thank you so much Rich, you've been a great help. Is there a chance you can take a photo of the cruise control unit on the driver side inner fender (if you still have one)? I think I have tracked it down to the cruise control unit, but I just need to make sure. The ball under the inner fender didn't have a vacuum line going to it. Although I've wanted and GN since it was new (I actually test drove a brand new one in 87 when it was new and I was young), I finally bought one last year before Christmas, it has 100100 miles on it, so I'm going through it to detail the engine and changing out all the hoses, oils, sensors, etc. I have been taking photos as I've gone along but didn't take photos of the vacuum line, there's a thick vacuum hose that's within the wiring harness going to the cruise control, but there's also a smaller nipple too on the unit, I believe the vacuum line in question goes there, but what about the vacuum ball under the fender? Thanks again!

Your welcome Chris, didn't do anything. Nice to see forum move along even though only two participating lol. Photo was from a selection on Safari, don't have a GNX but a big fan of them. Remember them new through the 80's also, nothing could catch up. Still see one in a blue moon.

Was thinking maybe to work diagram backwards. Check off what's known for certain and might narrow down through elimination? Sounds like maybe something maybe a prior owner didn't want connected. Is end capped off on hose, would indicate purposely secured for one reason or another. Vaccum must be a sealed system to function. Also try stretching hose out and by experimenting with different routings may give clue.

Nice project, now that's a Buick worth working with. Note: A check valve and A/C does show with cruise control circuit, concur. Oh too, hopefully correct diagram. May have one under hood someplace, used to. Ball under fender may relate to charcoal canister and line to fuel tank, egr recirculation? Test check valves also, may be defective. Can just blow air through those one direction only.

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Thanks again for all your help, I did find this diagram after search all over the web. I think I've narrowed it down and figured it out. I'm just happy to finally have a GN :).

Attachment 906

This might open better...

Nice find Chris not expecting that lol, thanks too on post follow ups. I'm in learning mode with Buicks and all their ideas outside the norm of thinking. For cruise control, wow. Servo would operate as cable control accelerator pedal. Put a cruise control in my '84 Daytona- way different from this though (many years ago).

Nothing like the whine of a turbocharger, almost like listening to a clock tic-toc. Hope to hear more on your project coming up.

Regards, Rich