Aftermarket June 2022

A waveform was captured from the vehicle with the starting concern and compared to a known good vehicle. Fig.2 and Fig.3 show the waveform for both vehicles. Fig.2 shows the pattern from a vehicle known to be good, while Fig.3 shows one known to be faulty. Yellow trace; Camshaft position sensor. Green trace; Crankshaft position sensor. NB: It must be noted that the amplitude and frequency of the traces will vary depending on whether the engine is cranking (no start condition) or idling. This is acceptable for this engine as it doesn't have variable valve timing. Engines with variable valve timing should be assessed under the same operating conditions. Closer inspection of the waveform shows a difference of 9 teeth. As there are 58 (plus two missing) teeth on the flywheel, each tooth represents 9°of crankshaft rotation. This equates to a difference of 54° of crankshaft rotation. Note; On this vehicle the crankshaft position sensor is inductive and the camshaft position sensor is Hall Effect. Please refer to Fig.4, the known good vehicle. Then refer to Fig.5, showing the faulty vehicle. Removal The Transmission, clutch assembly and flywheel were again removed to inspect this alignment of the flywheel. The alignment of the flywheel is a concern as this engine doesn't have a locating dowel to align the flywheel. Fig.6 shows a reference hole which must line up with a reference hole on the rear flange of the crankshaft. Once the flywheel was correctly aligned and the vehicle re-assembled the fault code cleared and the engine started and operated as expected. www.aftermarketonline.net JUNE 2022 AFTERMARKET 41 www.aftermarketonline.net Fig.1 Fig.2 Fig.3 Fig.4 Fig.5 Fig. 6 The amplitude and frequency of the traces will vary depending on whether the engine is cranking or idling ”