The cylinder power balance test is a way of measuring the ability of each cylinder to contribute an equal share of the total power output of an engine. On modern engine analyzers it is performed by depressing a series of switches that automatically short any one or a combination of cylinders while a tachometer indicates the drop in engine rpm. The speed drop variation among cylinders should not exceed 5% at idle. This test will point out a cylinder that is weak and not contributing its share to total engine output. The cylinder power balance test should be performed in conjunction with a scope test, when it becomes an ideal procedure for spotting cylinders that have compression problems. Ways of rectifying any imbalances are described. Leaking carburetor base gaskets that allow enough air to seep into the air-fuel mixture to cause a leaning out of some of the cylinders is discussed. Computerized engine analyzers and accurate exhaust gas emission testers can measure variations in total hydrocarbons (HC) as each cylinder is killed. This indicates the distribution and combustion efficiency. It is pointed out that before performing a power balance test on a car with an engine computer, one must put it into open-loop mode.

  • Corporate Authors:

    Hearst Books

    Motor Books Department, 224 West 57th Street
    New York, NY  United States  10019
  • Authors:
    • Cerullo, B
  • Publication Date: 1984-2

Media Info

  • Features: Photos;
  • Pagination: 6 p.
  • Serial:
    • Motor
    • Volume: 161
    • Issue Number: 2

Subject/Index Terms

Filing Info

  • Accession Number: 00391329
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: HS-037 093
  • Files: HSL, USDOT
  • Created Date: Dec 30 1984 12:00AM