With the growth of new technologies, such as hybridization and active safety systems, the electronic content will only continue to increase. If independent garages are going to be able to repair these vehicles efficiently, the scope and power of the diagnostics tools and test equipment they use must match the complexity of these systems.

Workshop Solutions

Support and services for Delphi Partners

About Us

With a presence in more than 150 countries, and a global network of over 2750 service centres, Delphi Technologies aftermarket provides OE specification end-to-end solutions from components to sophisticated software solutions.

Tech tips resource banner
Resource Center 4 min read

Hard or non-start problems due to fuel injection system

Share Resource:
Diagnostics & Test Equipment Fuel Injection Diagnostic Technical Tip DIYers Technicians 4 min read

Resource Highlights

In this article, you will find out about Hard or non-start problems due to fuel injection system.


Some 2.0 HDi vehicles may develop hard or non-start problems which can be attributed to the fuel injection system.

This may be due to failures in either the low pressure feed to the high pressure pump, or the high pressure pump itself.


The fault codes should be first read using the DS diagnostic kit and if pressure related faults are recorded the following process will aid repair.

For the low pressure system a feed pressure of at least 2.5 bar is required at the high pressure pump inlet. This can be measured with a low pressure gauge on a “T” connector fixed to the HP pump inlet under cranking conditions.

If the pressure is low or non-existent then the low pressure system must be repaired first. Common reasons for failure are:

  1. Blocked fuel filter / fuel contamination
  2. Failure or blockage of the low pressure supply pump
  3. Wiring issues to the low pressure pump

If the reason for failure is fuel contamination then the whole system must be cleaned out, and this may include major service of the high pressure components as well.

If adequate pressure is available from the low pressure circuit then the high pressure circuit should be checked for efficiency. A minimum pressure of 117bar is required to affect an engine start. This can be checked through the diagnostic port and by reviewing the dynamic data referring to rail pressure.

It may be possible that the data supplied is inaccurate due to a failure of the rail pressure sensor, but not necessarily creating a rail pressure sensor fault code in the process. It is also possible that low pressure is attributable to a leak in the system which is not visually detectable.

In order to confirm the high pressure pump efficiency in a ‘stand alone’ condition the Delphi sealed rail kit (YDT278) can be used to determine the pumping efficiency of the high pressure pump. If a pressure issue is found on the pump, then this is a serviceable item via the local Diesel Centre or Technical Partner. Note the pressure parameters in the information pack supplied with the sealed rail kit.

If the pump sealed rail test is okay then further investigation into possible leakage via the rail, high pressure valve, or injectors will be necessary. For Injectors a back leakage check using the sealed rail kit is possible, and again these are serviceable items via the Technical Partner.

If both low and high pressure requirements are met, poor and non-start situations should be avoided.

Tools & Equipment

Part Number




Diagnostic tool

Fault code reader


Sealed Rail Kit

Check HP pump pressure and backleak of injectors


The specified form no longer exists or is currently unpublished.

Related article resources and products

    Diagnostics & Test Equipment OBD Diagnostic

    Heavy Duty DS Diagnostic Software

    Our DS diagnostic software for trucks, trailers and buses is packed full of powerful features, functionality and applications for a truly heavyweight diagnostic capability. Available as a stand-alone VCI, DS150E or DS450E tablet, the intuitive software provides seamless diagnostics of the key vehicle systems across a wide range of heavy duty makes and models. On top of the standard programmes such as reading and erasing fault codes, it lets users reset adaptations for key systems such as EGR, air mass meter and EBS, perform dosing tests, regenerate the SCR system and calibrate suspension levels. Better still, an ever-expanding range of functions built-in to the software and VCI allows you to do all this and more with ease.
    Diagnostics & Test Equipment OBD Diagnostic

    DS Software-Car/Light Commercial Vehicle

    Our DS car and light commercial vehicle software is the brains behind our diagnostics. With just one licence , you can access in-depth diagnostics and advanced technical information for an extensive range of makes and models. Available as a stand-alone VCI, DS150E, or DS450E tablet, the simple, easy-to-use software provides fast and accurate diagnostics of the key vehicle systems. As well as the ability to read and erase fault codes, recode/activate components and reset service lights, the software is packed with intuitive features such as full system scans, VRM lookup, technical data, help files and a report function. Combined with the added capabilities built into the VCI, you’ll be able to perform even the most complex of jobs with ease. From the right equipment to the right diagnosis, DS Series diagnostic tools offer the options, performance and support that today’s shops are searching for.
    Diagnostics & Test Equipment Fuel Injection Diagnostic

    Electronic Injector Test Kit

    With today’s Common Rail injector technology, it’s no longer sufficient to just measure resistance to check a coil’s health – you also need to measure inductance for an immediate and accurate assessment. Previously separate tools would have been needed for this. Not with our Electronic Injector Test kit. Otherwise known as the ‘buzz tool,’ or part number YDT720, you’ll be able to quickly test the electrical integrity of all makes of solenoid Common Rail injectors on vehicle. The simple,hand-held tool measures the injectors core criteria, allowing you to quickly compare values and identify if any are not within a comparable performance range, or confirm specific electronic failures which may indicate an unrepairable injector. You can also use it in conjunction with our solvent cleaning kit to resolve early-stage lacquering. All with just one tool, saving significant time and cost for the garage.
    Diagnostics & Test Equipment Fuel Injection Diagnostic

    HD3000 High Pressure Diagnostic Tool

    Designed for specialist workshops, our patented HD3000, part number YDT840, simplifies the diagnosis of faults with current and future-generation diesel and gasoline high pressure fuel systems, on all vehicle types. With one tool users will be able to safely set and electronically control any pressure testpoint , up to 3000 bar, in order to investigate the full range of pressures and analyse the performance of the fuel injection system – previously this level of flexibility, accuracy and pressure capability could only be achieved with a system-dedicated test bench. Containing an electronic control device, hydraulic block and electrical device, it incorporates multiple dedicated test routines, as well as an IMV cleaning procedure. All this can be achieved without changing any ECU parameter, dismantling the fuel injection system, or taking the vehicle out on a road test – helping workshops save valuable time and deliver faster service turnarounds.
    Diagnostics & Test Equipment Fuel Injection Diagnostic

    LP35 Low Pressure Diagnostic Tool

    Designed for the garage technician, LP35, part number YDT810, is a highly precise, ultra-fast, affordable hand-held tester for the low-pressure side of light, medium and heavy duty vehicles. With a single tool, you can perform quick and accurate pressure analysis across a wide range of positive and negative pressures, from minus one through to positive 35 bar -that’s why we called it the LP35. Unlike other entry level equivalents, it’s also compatible with most low-pressure circuits, as well as different fluids, so you’ll no longer need separate negative and positive pressure tools, saving both time and money. Add to this its static and dynamic functionality, and you’ve got a highly versatile, highly capable low-pressure tool.
    Diagnostics & Test Equipment

    Fuel Injection Diagnostics

    Due to the design of today’s advanced fuel injection technology, electronic diagnostic tools require additional support to accurately trace faulty components – the ECU diagnostic software  can often go no further than failure mode identification, which does not always pinpoint the particular part of the system that has failed and can result in the unnecessary replacement of complete systems. That’s where we come in. We know exactly what is required when diagnosing this technology – after all, the chances are we designed and manufactured it in the first place. So, we’ve developed a range of simple, low-cost, on-vehicle diesel diagnostic tools to help you and your customer save time and money.
    Diagnostics & Test Equipment Fuel Injection Diagnostic

    Sealed Rail Diagnostic Kit

    Because Common Rail systems operate at extremely high pressures, any loss in pressure will have a knock-on effect on the vehicle – causing a progressive reduction in power and even a complete engine shut down. It is therefore imperative that any such issues are identified and resolved as early as possible. We have just the answer. Our Sealed Rail diagnostic kit, part number YDT850, provides simple, low-cost on-vehicle capability for all makes of Common Rail pumps and injectors. Consisting of a sealed rail pressure tester and injector back leakage measurement equipment, users can check the pressure being generated by a Common Rail pump and identify individual injectors that fail, meaning only faulty components will need to be replaced.

      Contact Us

      Visit our Contact hub to find a range of enquiry types suited to help you find the exact support you are looking for.


      Find your nearest Service & Diesel Centres