Manuals through 2025 now available!
Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.
LEMON is the spiritual successor to CHARM, I recommend you try it!
Link:
lemon-manuals.la or
lemon-manuals.org.ua
(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)
Or, hide this message:
temporarily or
permanently
Operation
The PCM uses a
KS in order to detect abnormal vibration in the engine, such as detonation, or spark knocking. Mounted in the engine block, the KS produces an AC signal at all engine speeds and loads. Next, the PCM adjusts the spark timing based on the amplitude, and on the frequency of the KS signal. The PCM calculates a normal level of engine noise, also known as the noise channel, from the KS signal. The noise channel consists of an upper and lower region. A normal KS signal should vary within the noise channel as shown in the Knock Sensor Signal - Normal. A KS signal outside the noise channel, as shown in Knock Sensor Signal - Knock Present, indicates spark knock. The PCM will then adjust the spark timing to eliminate the engine knock.