Cylinder Balance Test

WARNING: This page is about a different car, the 1995 Lincoln Mark VIII. However, it is still accessible from the selected car via links, so may be relevant.

This test helps identify a weak or non-contributing cylinder in engines with SFI fuel systems. PCM shuts off fuel supply to each injector and measures RPM drop. It computes variation between cylinders and identifies weak ones.

This test mode is entered from KOER SELF-TEST after all codes have been displayed. Within 2 minutes after codes have been displayed, lightly depress throttle (a 2-3 degree throttle angle is required, not a wide open throttle). After a brief stabilizing period, PCM will activate test procedure.

Test will be repeated if throttle is depressed within 2 minutes of final code output. During second and third test sequences, percentage of allowable variation between cylinders is reduced. Service codes displayed during this test identify weak or non-contributing cylinder. See CYLINDER BALANCE TEST DIAGNOSTIC TROUBLE CODES table.

If Code 90 is displayed during this test, system has passed test. If Code 77 is displayed, repeat cylinder balance test. If throttle is moved during this test, Code 77 will appear, indicating test is not complete. Repeat Cylinder Balance Test. Total test time is about 3 minutes.

CYLINDER BALANCE TEST DIAGNOSTIC TROUBLE CODES

Code	Application
90	Pass
10	Cylinder No. 1
20	Cylinder No. 2
30	Cylinder No. 3
40	Cylinder No. 4
50	Cylinder No. 5
60	Cylinder No. 6
70	Cylinder No. 7
80	Cylinder No. 8
77	Retest