Vacuum Loss?

[Prospeeder]

Well, i noticed when i give it too much gas, or pull a hill, or anything hard acceleration the vacuum is lost and Vents goes to the floor, and if i use the cruise, when it engages the Vents go to the floor and then it comes back, but if the cruise has to adjust itself u lose ur vacuum and the vents go to the floor. It shouldnt do this should it?

[GutlessSupreme]

You have a turbo.. of course vacuum is lost when you push on the gas boost = anti-vacuum.

 

That said, your vacuum check ball is bad. behind the driver's side fender, under where the battery is located. Good luck finding a good one.

[Prospeeder]

oh, that sucks, what causes them to go bad? how do they work? do they sell them genericly or GM only? and are the exspensive

[GutlessSupreme]

I dunno but they all do eventually. I've never looked into buying a new one, but don't waste your time with a junkyard one for sure.

[DaveFromColorado]

it's not actually a "check ball" there's a check valve in line that will only allow vacuum (so when you go into boost conditions the airflow doesn't reverse) - when the check valve goes bad, you see this problem - also if your vacuum canister goes bad you see this problem, whether you're N/A or Forced Induction.

 

You can get ANY vacuum canister to work, but first just make sure all your vacuum lines are routed properly and are not broken - then check that check-valve.

 

--Dave.

[digitaloutsider]

I still don't understand how/what that canister does.. You can ask me about most anything under a hood, but I don't even know where to start concerning the vacuum system. I don't even know what causes the vacuum! I'm an idiot

 

Care to explain?

[mfewtrail]

http://en.wikipedia.org/wiki/Manifold_vacuum

 

[paulo57509]

I still don't understand how/what that canister does.. You can ask me about most anything under a hood, but I don't even know where to start concerning the vacuum system. I don't even know what causes the vacuum! I'm an idiot

 

Care to explain?

 

Take a look at the diagram below (disregard the notes in red):

 

 

Under low vacuum conditions, the check valve isolates the HVAC and cruise control servo from losing vacuum. However, the HVAC and cruise controls still need vacuum. Vacuum under low vacuum conditions is provided to the HVAC and cruise control servo by the vacuum built up in the reservoir.

 

If you're losing the cruise and HVAC control, verify that the check valve, reservoir, hard plastic lines and hose connections aren't damaged/broken. There's part of the plastic line that runs near the battery and onto the reservoir that gets eaten away by battery acid and eventually gets brittle and breaks.

 

The check valve, vacuum lines and reservior are available from GM. I got my replacements from GM Parts Direct. The line assembly comes with the check valve. The check valve is also available separately.

[Prospeeder]

whats the part number for it, and how much are they?

[paulo57509]

whats the part number for it, and how much are they?

 

I'll try to dig up the invoice.

[DaveFromColorado]

Paulo - that's an awesome diagram!

 

anyhow, time for an education...

 

what causes the vacuum is the downward motion of the pistons when the intake valve is open (the intake stroke) this will create a vacuum in the cylinder, as long as the throtle is closed this vacuum is then also created into the intake manifold betwen the piston and the throtle plate (whether it be the butterfly of your throtle body, or the butterfly's of a carburetor, they all work the same) when you hit the throtle, vacuum is lost and more air is able to enter the cylinder, which in turn gives you your increased power/speed.

 

Diesel engines are different, as they have no throtle plate between the valve and the manifold, they are getting as much air as they are able to take in, they work a bit differently, to increase the power they add fuel, rather then adding air and fuel like a gasoline engine. Because of this way the diesel engines work is the reason why diesel engines need a vacuum pump to operate the HVAC systems, Transmission Detent systems, and some other systems. Most diesel engine'd vehicles will use the power steering pump as a hydraulic assisting method for the brake systems.

 

does that clear it up a lil' for ya?

 

--Dave.

[LukeZ34]

Make sure you don't have any cracked vacuum hoses or anything of the sort.

I just repaired the same problem you are having a month or so ago.

I was changing out the battery for a new one, and I found the vacuum line that goes to the check ball was cracked in 3 places, causing a huge vacuum leak, and resulted in losing air controls under boost. Replaced that small section of line and the problem went away 100%.

Check the lines and all of the vacuum connection before you start replacing stuff.

[cutty]

my cutlass does the same thing, but only when i have it set to cold. it all starts blowing to the floor at any thing above 2k RPM. ill have to check my lines out and the check ball thing also this weekend.

[paulo57509]

whats the part number for it, and how much are they?

 

I'll try to dig up the invoice.

 

Okay, I found the GM Parts Direct invoice and the part numbers.

 

10063145 - Hose assembly that runs from the engine to the one-way valve; List: $11.84, Net: $5.92

 

10192799 - Hose assembly that runs from the one-way valve to the tank (reservoir) under the front fender; List: $12.02, Net: $6.00

 

The one-way valve is included with one of the hose assemblies, but I can't remember which one.

 

14056624 - Tank (Vacuum Reservoir); List: $18.18, Net: $9.09

 

10456648 - Valve (One-way valve); List: $5.46, Net: $2.73

 

Handling: $9.78

Shipping: $6.59

 

Keep in mind that these part numbers are for a 1992 Lumina, 3.1L and the prices are 09/2002 prices. YMMV.

[Prospeeder]

haha 10$ for the thing, ill get a 20 and go to my dealer

[Prospeeder]

ahhhh Dealer wants 60$ fuck that, i go to gm parts direct, 10$, part # 14056624