It is all about getting it right first time…
A smoke test ensures there is no misdiagnosis
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Think of an engine as a big air pump. It requires air to run an gasps for it at each time a cylinder fires. Under normal driving the throttle valve is rarely fully open, as such the engine is forced to draw air through a partially closed throttle valve. This creates a vacuum in the intake manifold.
Breather pipes are a favourite for splitting as they age, due to the fact they go brittle with time. If one of these pipes split it can be very hard to diagnose as the inlet manifold obscures a visual inspection. This is where a smoke tester becomes the most valuable tool in the workshop as BMW’s are riddled with breather pipes.
When one of these hoses, pipes, fittings, CCV or joints start to leak, the problems can range from an erratic idle (as the ECU is constantly attempting to compensate) to a EML light.
A fault that is ignored can lead to more serious faults long term! Burned out engine valves are one of the more serious as the engines ECU cannot correct the air/fuel ratio.
The video below shows our smoke test machine in action. This Alpina B3s had issues idling, down on power and the EML light on. Simply testing the vehicle electronically to diagnose the EML light issue was not enough as it can only pick up a fault to the nearest sensor. Many vehicle repairers spend hours attempting to fix a fault by wrongly replacing various sensors (at your cost), this repair was as simple as a new valve cover gasket.