The systems use an individual injection pump mounted on the engine block for each cylinder so it is primarily designed for OHV or "cam in the block" engines.[3] The fuel pumps can be either driven by an extra camshaft lobe or by an electrical supply where each pump unit is connected to the injector via a short precise length high-pressure fuel line as opposed to unit Injector systems which combines both a pump and an injector element in a compact unit.
Both systems feature electronically controlled fuel solenoids for precise timing and the injection of fuel quantity is variably adjusted for each cylinder.
^R. Bosch. "UPS Unit Pump Systems". Retrieved 5 December 2009.
^Diesel Fuel Injection. Germany: Robert Bosch GmbH. 1994. p. 147. ISBN 1-56091-542-0.
^Delphi. "Delphi electronic unit pump". Archived from the original on 20 April 2016. Retrieved 5 December 2009.
^Liebherr. "Liebherr Diesel engine D934 L A6" (Web). Retrieved 17 March 2014.
^Freightliner Trucks. "Freightliner business clas M2 line of trucks" (PDF). Freightliner LLC. Archived from the original (PDF) on 17 January 2009. Retrieved 5 December 2009.
^Freightliner Trucks. "Freightliner Columbia" (PDF). Archived from the original (PDF) on 11 June 2009. Retrieved 5 December 2009.
^Detroit Diesel. "MBE 4000 engine". Retrieved 5 December 2009.
^Western Star Trucks. "MBE400". Retrieved 5 December 2009.
^Freightliner Trucks. "Freightliner Columbia" (PDF). Archived from the original (PDF) on 11 June 2009. Retrieved 5 December 2009.