We received a call to confirm or deny diagnosis of the fuel pump on a common rail diesel Vauxhall Corsa. The owner was expecting the worst after diagnosis by the local main agent.
However using some quick serial data tests showed normal rail pressure, pressure regulation duty cycle and using the scope the pressure build and decay all looked to be with normal limits.
This was a good example of an all approaches diagnosis.
Good serial data, backed up by live scope readings, however the vehicle still had a miss fire once started from cold or after touching the accelerator if started from warm.
A quick look at exhaust manifold temps using an infra-red thermometer showed cylinder 4 to be the culprit. Suspecting poor servicing in the past an engine flush and service restored normal operation.
Much cheaper than a high pressure fuel pump!
