CARRIER 6Y3982 - Caterpillar

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Manual Override Signal, Timing Control In Electronic Timing ModeSent from Timing Control (pin-e) to CIS (pin-C, 10 pin Connector).The manual override signal should remain below 1 V when the system is in Electronic Timing Control mode. A 5 V signal on this line will tell the CIS to run the ignition at fully advanced timing. Ignition Pulses
The Ignition Pulse signal is the odd number bank's capacitor charge. The signals waveform indicates the discharge of the CIS and firing of cylinders. One pulse is shown for each number cylinder. This signal is used by the TCM to calculate ignition timing and some ignition diagnostics.
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Ignition Pulses Relative To Crank Angle TC Signal (Six Cylinder Engine)
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Close up Of Ignition Pulses Relative To Crank Angle TC Signal (Six Cylinder Engine)Sent from CIS (pin-A, 10 pin Connector) to Timing Control (pin-c).From TC to TC, this waveform should show one pulse for each number cylinder. The pulse is normally at 5 V and goes below 2 V when the CIS detects the ignition firing.Interaction Of The Interface Signals
The manual override signal is held below one volt, the CIS is placed in "Mag Cal" Mode. The TCM generates the Clock signal by squaring the Speed Sensor (TCMPU) signal. This clock signal is used by the CIS electronics in order to keep track of the rotational position. When the the Reset pulse is received from the TCM, the CIS counts nine Clock signal edges. The CIS will then signal to fire Cylinder Number One. The CIS continues to monitor the Clock. The CIS signals to fire the remaining cylinders through the rotation. When the CIS discharges to fire the cylinder, an ignition pulse is generated. The Ignition Pulse signal is a reduced voltage signal of the odd number bank's capacitor voltage. Ignition Timing is calculated by comparing the timing offset between TC from the Crank Angle Sensor and the Ignition Pulse for Cylinder Number One.When the Manual Override signal goes above one volt, the CIS operates in Manual (Standard) Mode. The CIS will no longer control ignition firing. The CIS will generate an ignition pulse at the most advanced ignition timing.The Ignition Timing is calculated in the same manner as in Electronic Timing Mode.
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Interaction Of Reset, Clock, Ignition Pulse And TC SignalWhen the CIS receives the Reset Pulse, the CIS generates a ignition pulse after 9 Clock Signal edges (both rising and falling edges). The CIS generates the Ignition Pulse for Cylinder Number One. This should occur before the TC signal of the engine.Ignition Pulse Firings
From TC to TC, this waveform should show one pulse for each cylinder. The pulses should go from 190 V to ground when the cylinder is signaled to fire.CIS Wiring Diagram
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G3612 Engine CIS Wiring
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G3616 Engine CIS WiringEngine Start-up
At engine start-up, the Timing Control performs some system checks not done once the engine is running. The Manual Override signal places the CIS in Manual Mode until the engine speed is above 500 rpm. The Timing Control