If there are vacuum leaks, then the computer must shoot for a “fuel rich” condition to prevent running lean, which could damage the motor with pre-detonation.

Sometimes vacuum leaks will whistle or hiss and make itself obvious.

But oftentimes, a vacuum leak will disguise itself as an ignition or fuel problem that defies diagnosis. Either way, an engine vacuum leak is bad news because allows “unmetered” air to enter the engine and upset the air/fuel ratio.

So, The effects of vacuum leakages can be summed up to three:

  • Poor fuel efficiency
  • Loss of power
  • Engine damage

Poor fuel efficiency happens when your car engine is having difficulties maintaining a good air/fuel ratio. The leaking of unmetered air into your vehicle sets this air/fuel ratio off balance.

Symptoms of a vacuum leak

A vacuum leak will cause the engine to run lean. In other words, there will be more air entering the engine than is needed to balance out the air/fuel ratio. This can result in the following:

  • Engine stalling
  • A rough running engine
  • Too fast of an idle
  • Hesitation
  • Increased emissions
  • Poor fuel economy
  • An illuminated check engine light

Finding Vacuum Leaks

Another way to find an elusive vacuum leak is to pressurize the intake manifold with about three lbs. of regulated air. This can be done by attaching a regulator to your shop air hose, then attaching the hose to a vacuum fitting or the PCV valve fitting on the intake manifold, carburetor or throttle body. Do not apply too much pressure or you may create new leaks!

With the engine off and air flowing into the manifold, spray soapy water on suspected leaks. If you see bubbles, you have found the leak.

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Vacuum Leaks
Vacuum Leaks

In conclusion, Just remember, locating and fixing vacuum leaks is easy if you do it in a systematic manner. Just be patient, and everything will go smooth and stress-free!