🚗 Classic Fault — Mercedes-Benz W115 (1968–1976)
Points ignition misfiring under load
💰 Estimated Repair Cost
$10 – $40 USD
Parts and labour estimate
🔧 Tools Required
Feeler gauge, dwell meter, timing light, screwdrivers
📋 Overview
Engine misfires particularly under acceleration or at higher RPM. Points ignition systems require periodic adjustment. The W115 uses a Bosch distributor with contact breaker points that wear and require adjustment every 10,000-15,000 km.
🩺 Symptoms
- Misfiring under acceleration
- engine stumbles at specific RPM
- backfiring
- reduced power
- rough running at high speed
🔍 Possible Causes
- Worn or incorrectly gapped points
- faulty condenser
- distributor cap carbon tracking
- rotor failure
- incorrect ignition timing
- old HT leads
🛠️ Diagnosis Steps
- Check points gap — should be
- Check dwell angle — should be 50-54 degrees.
- Test condenser with multimeter.
- Inspect distributor cap for cracks.
- Adjust ignition timing to 10 degrees BTDC.
✅ Most Confirmed Fix
Replace points and condenser as a set. Set gap to 0.4mm. Set timing to 10 degrees BTDC.
88% of users confirm this fix worked (31 reports)
🏷️ Parts Needed
Bosch contact breaker points set; Bosch condenser
🩺 Related Symptoms
🔗 Other Mercedes-Benz W115 Faults
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