2002 F150 XLT 4.6L V8

I have reason to suspect there is a vacuum leak somewhere. I have further reason to suspect that some of the hoses are either cracked or otherwise not up to par. How do I check to see whether there is a power leak?

 

Using a can of engine starter fluid spray the suspected hoses and connections. If the engine speeds up while you are spraying the leak is in that area. When the fluid gets sucked into the engine via the leak it casues the engine to speed up because it mixes with the air that is also being sucked into the engine.

JMC

 

Please take care though when using the starter fluid/carb cleaner/brake clean method. Yes, they work great for finding vacuum leaks, but they also work great for finding leaking plug wires. Ask me how I know.

 

Hey Quintin can you explain? I know where your headed I think, but would like to hear your story. (I think I had a similar exp.) I lost some facial hair!

 

i used the small propane torch and put the propane on a small amount and run it over the vacuum lines the propane caused the engine to idle up
antelope555

 

Well, there's two stories that stand out in my mind, one with me and one with a guy I worked with. First, me. Looking for a vacuum leak in a friend's '95 Mustang. Okay, no problem, start spraying around the intake manifold, got a little too close to the distributor and WHOOSH! Yes, eventually, my eyebrows did grow back.

A more recent one involved a guy I worked with. He was finishing up a 3.8L head job on a Taurus. Took it on a road test, came back and left the oil filler gap off, spraying oil all over the front of the motor. So, he leaves the engine running and takes off to spraying brake clean around the exhaust and spark plugs to clean the oil off. The whole building rocked with the concussion from the flame. He runs across the shop like a cartoon, smoke trailing from his head, blew his eyebrows off and singed all the hairs on his arms.

So do be careful when looking for vacuum leaks with flammable chemicals.

 

YES! Thank you! I am not the only one!!

 

I really like the method of attaching a vacuum cleaner to the exhaust pipe. After you have a good strong connection, and no leaks around the pipe, you can use some type of smoke device around the engine compartment. Anywhere that you see smoke going into the engine is a possible vac leak. Just using smoke is much safer than flammable liquid. Or if your not to hip on using smoke you can spray some water around the engine. A little water in the combustion chamber should not be a big problem.

Or you can just look for the obvious hose off. Not to many on these new ones. Unless you have a leak around the intake gasket. I just had one on my old 72 at the power brake booster. Seems it was the booster that was leaking.

Did I miss it or did you say what the motor was doing or not doing?