Frustrating VW Golf R Diagnosis: The Insane Mystery of Why It Won't Start

Initial Diagnosis and Frustration

• 💡 The 2015 Volkswagen Golf R, brought to Rich Rebuilds Garage, wouldn't start despite having fuel pressure, a crank signal, and spark.
• ⚠️ The oil pan was smashed, but the engine bearings appeared undamaged, suggesting it wasn't run without oil.
• 🛠️ Initial checks included fixing the oil sensor, clearing codes (ABS, airbag), and verifying fuel pressure (2200 PSI) and crank signal.

Spark, Fuel, and Compression Checks

• ⚡ A physical spark test confirmed spark was present, but the spark plug remained dry, indicating potential injector issues.
• ⛽ While fuel pressure was verified, the injectors were not definitively confirmed to be opening, despite startup enrichment signals.
• 🧯 Attempts to start the engine with starting fluid (carburetor cleaner) yielded no results, ruling out fuel system issues.
• 📊 Compression tests showed good results across all cylinders, further deepening the mystery.

Mechanical Timing and Expert Opinions

• ⚙️ Experts Joe and Lee, specializing in VW and Audi, were brought in but also stumped by the lack of any engine cough or codes.
• 🔍 The possibility of mechanical timing being off was considered, leading to the removal of the front timing cover.
• ⚠️ A theory emerged about a broken micro-screen in the camshaft adjuster bridge potentially jamming a phaser, but inspection of the components didn't immediately confirm this.

The Breakthrough and Lingering Mystery

• 💡 The Golf R eventually ran when the spark plug wires were reversed and the firing order was flipped, a temporary workaround.
• 🔌 Further testing with the exhaust camshaft position sensor unplugged allowed the engine to run seemingly perfectly, albeit with a code for the sensor.
• 🤔 The exact cause remains a mystery, with theories pointing to the camshaft adjuster, a jammed cam, or a default engine computer setting when the sensor is unplugged.
• 🚗 The car was eventually moved to Joe's shop for further diagnosis, with the owner planning to return to help uncover the root cause.