Vacuum Leak

[JoshMcMadMac]

Recently I have noticed a hissing from inside the car while driving. I start the car, and the hiss is noticable from what would seem to be somewhere inside the dash. It gets slightly quieter if I put it in gear. But I have discovered that it disappears completely when the car is under load. When I am accelerating, the noise is gone. Any idea where this is coming from, and how difficult it will be to fix?

 

[CaptainZilog]

Well, there is the automatic e-brake release. Does that function work for you?

 

[SC_Steve]

spray some carb cleaner around the engine bay, when the engine surges, your close to the leak

edit: n/m just noticed inside the car part.... hmmm... good question. Was your A/C on?

 

[JoshMcMadMac]

It still works, but I think it is the vacuum line from the shifter. Unless anyone has a better idea or more information, it's getting a Duct tape fix.

 

[JoshMcMadMac]

spray some carb cleaner around the engine bay, when the engine surges, your close to the leak

Thanks man, but it's inside the car.

 

[CaptainZilog]

It still works, but I think it is the vacuum line from the shifter. Unless anyone has a better idea or more information, it's getting a Duct tape fix.

Well, if you have a way of sealing off a vacuum tee, look on the firewall by the MAP sensor. There should be a vacuum tee, shaped like the letter y. the smallest hose is the hose for the automatic parking brake release. Pull the hose off and block off the tee and get in the car and see if it still hisses.

 

[JoshMcMadMac]

Thanks, Capt. That should make it easier to troubleshoot than ripping into the console. And I rarely use the parking brake, so I can disconnect it until I have time to fuss with it. Where is the MAP sensor hiding?

 

[CaptainZilog]

MAP Sensor is on the firewall, next to the master brake cylinder, on the driver's side. It's a non-descript black box, about 2/3'rds the size of a pack of cigarettes. Has one vacuum line and one 3-wire harness going into it. You might have to hunt around a little to find the vacuum tee I'm referring to, but it's there.

 

[JoshMcMadMac]

Ok, I think I know what you are talking about. I believe I encountered it when I replaced intake and valve cover gaskets. I'll check it out, thanks!