Adjusting the adjuster screw on a Vag Camshaft affects the pressure wave buildup and duration of fuel injection. This adjustment alters when the injector “pops” or sprays fuel, significantly impacting the engine’s timing. While a static timing setting provides a baseline, altering the screw renders the static timing marks on the mounting bracket and the timing gauge readings less reliable.
The factory static timing specifications are established based on a bench machine calibration of the pump. Once the adjuster screw is manipulated, the pump’s pressure and injection duration deviate from these specifications. Consequently, the static timing setting becomes meaningless because the pump is no longer calibrated to the original benchmarks.
Tampering with this screw can lead to significant starting problems, particularly in high-altitude environments like Colorado. Even minor adjustments can disrupt the timing enough to prevent the engine from starting cold. Attempting to use a timing gauge to correct this issue on an engine with an altered adjuster screw is often futile. This is based on 18 years of experience working with these engines. In regions like North Carolina, where this screw is typically untouched, the static timing setting remains a valid reference point for engine timing. However, in areas where adjustments are common, relying on static timing alone becomes problematic. A bench machine is necessary to recalibrate the pump and restore accurate pressure and injection duration, effectively resetting the timing to factory specifications.
