Hissing noise, car can't hold idle...

iwannanSC

Registered User
Hey,

Just finished (or so I thought) working on the car, and started it up. There is clearly a hissing noise coming from the engine, and the car can't hold idle. If I keep on the gas it will run, but if I let off, it dies. I just did all kinds of work to the car. Some things are fuel pump & filter, alternator, belts, rear rotors & pads, one rear bearing, and "new" (junkyard) front hubs. Hoping to get the car inspected this week so I can get it on the road. If anyone has any suggestions PLEASE let me know.

Thanks for your time,

Matt
 
You've described a vacuum leak exactly. Look for any loose hoses, try to listen for exactly where the leak is coming from. You might have to replace a hose somewhere or something, but it shouldnt be that difficult.
 
It sounds like it's coming from the rear of the engine on the passenger side, like behind the supercharger. Do you think it's a regular hose or a supercharger tube? Also, that part of the engine feels VERY hot after only a few mins of run time, much hotter than it should be.
 
PCV Valve is back there. Work with a friend to fully isolate it by listening under the hood when the friend kills the engine. Typically the noise will continue a moment after the engine stops, but all the engine noises go away first so you can pinpoint it better.
 
There's a vacuum line that comes out of the fender that connects to the back side (where you can't see it) of the PCV valve hard line. But since you say it gets hot very quickly in the area I would be looking at the EGR valve and it's gasket for leaks of hot exhaust.

Vernon
 
Thanks!

Thanks guys,

I got a brand new boost-capable PCV Valve from the Ford dealer, and when I went to put it in today my friend and I found that the other end of that line that the PCV valve plugs into was unplugged from the back of the supercharger. That was my leak. Just bought the car a few weeks ago, so I don't know how long it's been that way. Anyway, thanks for all the advice.

Matt
 
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