Tandem Pumps

A tandem pump can be simply described as a low pressure fuel pump in a diesel engine which also includes a vacuum pump. They are used on engins with unit injectors and supply the fuel to the units.

A number of lorries on the road today use unit injectors, but smaller commercial vehicles and some cars use unit injectors – particularly cars in the VW group.

The use of tandem pumps is diminishing in the industry because of tighter emission regulations.

It is called a tandem pump because it has two functions: the first function is to act as the vacuum pump for the brake servo and the control circuits for the turbo and EGR, the second function is to supply fuel at approximately 8 to 8.5 bar to the galleries in the cylinder head and to the fuel injectors. The injectors are there to pressurise the fuel to very high pressure (2200 bar approx).

It is a complex and relatively expensive unit to manufacture and was ultimately replaced by the common rail system that has an external delivery injector system replacing the cylinder head galleries and all the other major engineering associated with the manufacturing process.

At Darwen Diesel we supply tandem pump repair kits, whereas original equipment manufacturers do not. They want you to simply purchase the pump. Our range includes vacuum tandem pump repair kits as well as all of the gaskets and seals you would need for Audi, Seat, Skoda and Volkswagen EUI diesel engine systems fitted to 1.2, 1.4, 1.9, 2.0, 2.5 and 5 litre diesel engines.

Our range includes complete repair kits as well as metal gaskets, oil seals and torx screws which are available separately.

If any part associated with vacuum tandem pumps that you are looking for does not appear in our range, please do not hesitate to contact our technical or sales team and we will be only too happy to try to source the part or parts for you.