Using Differential Diagnosis To Identify Engine-Vacuum Leaks - High Performance Pontiac Magazine ...

An engine with a good, broken in cylinder seal will show 2- to 3-percent leak-down, while 6 to 10 percent is acceptable for an engine with unseated rings.

What to do: Verify fuel pressure using a fuel pressure gauge. With the vehicle running, pressure should increase when the regulator’s vacuum source is disconnected and plugged.

One of the reasons your engine light came on might be because of a vacuum leak. Here's how to check if one occurred in your vehicle's engine.

[JustinN1] developed both a boost/vacuum gauge and an oil pressure gauge, both useful for keeping an eye on what the engine is doing. Measuring boost is as simple as using an off-the-shelf analog ...