🔍 Key Concepts

• Relationship between compression pressure and sealing of valves/piston rings • How combustion timing or quality affects exhaust gas temperature • Differences between air supply problems and exhaust flow problems on cylinder temperature and compression

💭 Think About

• If compression pressure is lower in one cylinder, what kinds of leaks or defects would cause that, and where would they be located? • Which condition would most likely cause hotter-than-normal exhaust gas from that cylinder, and why would incomplete sealing affect temperature? • Compare which answer choices would change the air going into the cylinder versus the gases going out of the cylinder, and how each would affect compression readings.

✅ Before You Answer

• Be sure the option you choose can both reduce compression pressure and raise exhaust gas temperature at the same time. • Verify whether the condition would occur in a single cylinder or would normally affect all cylinders equally. • Confirm that your choice directly involves a leak path or restriction that could cause hot gases to pass where they should not, increasing that cylinder’s exhaust temperature.