Black Star Diesel Generator

Generator set manufacturer and model number of this diesel genset would be helpful.

What advice does the operations manual offer?

It is highly unlikely that the bias signal out of range is the cause of the engine cranking but not firing. Fuel in the correct amount and timing and compression are the two things needed to make a diesel engine work.

The bias signal is likely linked to droop operation, but without further information, it is a useless troubleshooting tip.

Cranking with no combustion on a diesel comes down to fuel quantity, fuel timing or compression – the bias signal is almost certainly a red herring, since it sits in the speed/voltage droop loop and cannot stop the engine firing.

On a set that has been standing, work the fuel path first:

• Confirm the fuel shut-off solenoid / rack actually pulls in during cranking.
• Check the low-pressure side for a clogged or air-leaking element. A blocked or water-loaded fuel filter water separator is the most common cause of crank-no-fire after storage, and a weeping filter-head gasket or drain lets air in so the transfer pump never builds pressure.
• Bleed the system properly, then read transfer-pump pressure at the injection pump inlet.
• Only then check rack travel and injection timing.

As a quick confirmation: if it cranks at normal speed and you get no exhaust smoke at all, that points to zero fuel being delivered rather than a timing fault. If you do replace the element, fit a genuine coalescing type (fuel water separator filter) rather than a plain screen strainer, and re-bleed to the injectors afterwards.