Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1987 Mercedes Benz 560SLFACTORY OEM SERVICE PROCEDURE
Fuel Injection System - BOSCH Cis-E
- Description
- Operation
- On-Board Diagnostic Readout System
- Fuel Pump Relay
- Cold Start Valve Activation
- Fuel Enrichment
- Fuel Pump
- Diaphragm Pressure Regulator
- Fuel Distributor Unit (FDU)
- Coolant Temperature Sensor
- Electronic Control Unit (Ecu)
- Idle Speed Control Unit
- Idle Speed Air Valve: 190E, 260E, & 300E
- Idle Speed Air Valve: 420 & 560
- Voltage Protection Relay (VPR)
- Oxygen Sensor
- Lambda Control
- EZL Ignition Operation
- Diagnostic Testing: 420 & 560 Series
- Test 1: Testing Voltage Supply To Cis-E Control Unit
- Test 2: Testing Airflow Sensor Position Indicator
- Test 3: Testing Full Load Contact & Airflow Sensor Position Indicator
- Test 4: Testing Coolant Temperature Sensor
- Test 5: Testing Airflow Sensor Position Indicator
- Test 6: Oxygen Sensor Test
- Test 7: Testing TD Signal
- Test 8: Altitude Correction Capsule Test
- Test 9: On-Off Ratio Test
- EZL Ignition Testing: Engine Not Running
- EZL Ignition Testing: Engine Running
- Component Testing: 420 & 560 Series
- Component Testing: 190E, 260E & 300E
- Airflow Sensor Plate
- Cold Start System
- Fuel Delivery & System Pressures
- Electrical Components
- Fuel Pump Relay
- Coolant Temperature Sensor
- Acceleration Enrichment
- After-Start Enrichment
- Deceleration Shut-Off
- Full-Load Enrichment
- Overvoltage Protection
- Altitude Correction
- Lambda Control
- Oxygen Sensor
- Oxygen Sensor Heater
- Electronic Idle Speed Control
- Idle Speed Stabilization (Automatic Transmission Engaged)
- Idle Speed Stabilization (A/C Compressor Engaged)
- Throttle Valve Switch
- Trouble Shooting: 420 & 560 Series
- Wiring Diagrams
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.