A recent timing belt replacement on a Mk7 1.4L TSI engine resulted in random misfires across all cylinders, flashing check engine light, and an Auto Start/Stop error. Initially, the garage diagnosed the timing as being off by a tooth and corrected it. However, the problem reappeared after a short period of normal driving. Despite the garage’s reassurances and a VCDS timing check on their end, the issue persists. This article dives into using VCDS to analyze camshaft adjustment values and determine if the timing is indeed the culprit.
Using VCDS for TSI Engine Timing Analysis
After the initial repair, the car ran smoothly for approximately 50 miles before the misfires returned. The garage re-checked the timing, spark plugs, and coils, claiming everything was within specification. However, a personal VCDS scan revealed some questionable camshaft adjustment readings.
The following data was recorded using VCDS:
First Reading (After Initial Repair):
- Mileage: 79460km (49374mi)
- Repair Order: 220421
- Address 01: Engine (04E 906 016 DE)
- 10:12:05 IDE00178 Camshaft adjustment intake bank 1: specified value 17.492 °
- IDE00179 Camshaft adjustment intake bank 1: actual value 17.664 °
- IDE00182 Camshaft adaptation intake bank 1: phase position 0.00 °
Second Reading (After Misfire Recurrence):
- Mileage: 79460km (49374mi)
- Repair Order: 00001
- Address 01: Engine (04E 906 016 DE)
- 19:42:48 IDE00178 Camshaft adjustment intake bank 1: specified value 17.492 °
- IDE00179 Camshaft adjustment intake bank 1: actual value 17.336 °
- IDE00182 Camshaft adaptation intake bank 1: phase position 4.83 °
Two key observations emerged:
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Camshaft Adjustment Intake Bank 1 Actual Value Increase When Engine Off: The actual value increased by approximately 5 degrees after the engine was switched off, reaching around 22 degrees. This significant jump suggests a potential timing issue.
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Camshaft Adaptation Intake Bank 1 Phase Position Instability: The phase position initially read 0.00° but increased to 4.83° after running for a short period. In the first reading, it also increased from 0.00° to 4.42°. A stable phase position near 0° is expected. This fluctuation further points towards a potential timing problem. While the specified and actual values for camshaft adjustment are relatively close at idle, the other inconsistencies raise concerns.
Conclusion
The VCDS data, particularly the fluctuating phase position and the jump in actual camshaft adjustment value when the engine is off, strongly suggests that the timing may still be incorrect despite the garage’s efforts. Further investigation is necessary to pinpoint the root cause of the misfires. It’s recommended to consult with a specialist familiar with VW TSI engines and VCDS diagnostics to ensure accurate timing adjustment and resolve the issue.
