Detonation Control System Test (200 Models Only) - Mercury 150 EFI Service Manual

FUEL INJECTION

Detonation Control System Test (200 Models Only)

a -
Purpose: Determines whether the detonation sensor and circuit located in the ECM is functioning.
1. Place outboard in water, connect Digital Diagnostic Terminal (DDT) to engine.
NOTE: If either knock sensor is not functioning, #4 LED indicator light on DDT will be illumi-
nated.
2. Start engine, allow to warm up. Using SPECIAL FUNCTIONS portion of DDT, access
KNOCK OUTPUT LOAD TEST.
Results: As throttle is advanced and engine is under load (in gear), numerical value on DDT display should
increase. As throttle is retarded, numerical value should decrease indicating knock sensor/circuit is
functioning. If numerical value does not change as throttle setting and load on engine varies, knock
sensor or knock circuit in ECM is defective.
Page 3B-32
149
140
131
122
113
104
95
86
77
68
59
50
41
32
14
5
a
Knock Sensor
65
60
55
50
45
40
35
30
25
20
15
10
5
0
–10
–15
a
2083
2488
2986
3603
4370
5327
6530
8056
10000
12493
15714
19903
25396
32654
55319
72940
58893
90-883728 JULY 2001