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Common Rail and E.U.I./P.P.D. Spares


  • Electronic Unit Injector (EUI) Parts

    Darwen Diesels stock a range of parts for Electronic Unit Injectors (EUI’s), but we also have a stock of the Injectors themselves. If we don’t have the EUI you particularly require, we are very happy to recondition any unit you have. If you send it to us, we aim to have it reconditioned within a day and back to you within 48 hours, depending on our volume of work and the availability of parts.

    Core to the construction of an EUI is the plunger pump. This allows for low-pressure fuel delivery and return to all injectors, but at the same time provides extremely high- pressure atomisation and injection of diesel to a cylinder during an engine’s power cycle.

    There are four phases in a EUI’s operation:

    1. The fill phase is where there is a retraction of the plunger pump and diesel fuel is then drawn into the pump.
    2. The spill phase is where the plunger pump starts to descend and the spill valve is open with diesel going back to the return line.
    3. In the Injection phase the solenoid is activated, closing the spill valve. This occurs partway through the pump stroke; the diesel is forced through the nozzle creating a spray pattern in the cylinder.
    4. Finally, in the pressure reduction phase, the spill valve is re-opened, almost at the end of the pump stroke, and diesel is allowed to recirculate again, ending the injection phase.

    Electronic Unit Injectors, were designed mainly for use in commercial vehicles and large HGV’s, but they were used by Land Rover and Volkswagen for some passenger car diesel engines. EUI’s have been manufactured primarily by Bosch and Delphi, and we have appropriate parts for those EUI’s in stock.

    Over time, and particularly since the advent of new tighter emissions standards, the use of Electronic Unit Injectors has declined and Common Rail has become the main system used for most diesel engines. It is also true to say that a small handful of manufacturers such as Scania and Volvo still use EUI’s for their trucks and heavy commercial vehicle.

Showing 1 - 11 of 11 items
Showing 1 - 11 of 11 items

We are one of the UK’s largest stockists and suppliers of common rail diesel spare parts, we stock a very broad range of tools and test equipment as well as Electronic Unit Injection (EUI) and Piezo Pump Deuce (PPD) spares. Fundamentally, our spares range covers the parts required needed to rebuild and recondition Common Rail pumps and Injectors. We also stock some pre-common rail parts too. In total, we have over 20,000 different part numbers available for next day delivery.

Our range includes cap nuts, seal kits, nozzles including Firad nozzles (as we are the UK agent for Firad), injector seating washers, pilot valves, high pressure seals and leak-off connectors. In terms of pre-common rail parts, we have conventional type diesel pumps and diesel injectors such as Simms inline pumps, Bosch in line and VE rotary pumps, CAV DPA and DPC rotary pumps, Denso pumps, Zexel pumps and Bryce single cylinder pumps. We also have Corona diesel test equipment (as we are also the UK agent for Corona Diesel) and spares in stock.

Probably just as importantly, we have the technical expertise, knowledge and experience to be able to advise our customers on the correct part to use for a particular application and particular engines. Please call us to discuss your specific needs. We will even try and source a part for you if we don’t have it in stock.

Our website has a database of items that we stock, but not all of them, so contact us if you can’t find it on 01254 53545. Our sales and technical staff will be only too happy to help.

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We can source virtually any diesel part!

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  • We hold vast stocks of OE and quality replacement parts
  • We can source virtually any diesel part
  • The largest UK independent distributor of Diesel Fuel Injection components
  • We export our products to worldwide destinations
  • Next day delivery

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Overseas Orders

For orders to be delivered outside of the UK, please contact us or send us a message so we can quote for delivery.