THE T-HP KIT - HIGH PRESSURE DIAGNOSTICS FOR DFP3 COMMON RAIL PUMPS

The T-HP diagnostic kit (YDT465) provides workshops with the ability to carry out in-depth mechanical diagnostics on Delphi’s range of DFP3 Common Rail pumps.

DFP3 pumps are the latest generation of Delphi Common Rail pumps, providing a higher pressure capability and more stable pressure control than its predecessor, the DFP1 pump. In order to achieve this improved performance, there have been a number of changes to the pump, including the move from a single-cylinder to a multi-cylinder design. This means that each pumping plunger has its own non-return valve and hence a faulty DFP3 is still capable of producing a high pressure.

Therefore the conventional Sealed Rail kit cannot identify 100% of failures on a DFP3 pump. It will still diagnose faults that lead to an engine not starting. However when there is a fault but the engine does start, a new diagnostic approach is required for the pump.

The T-HP diagnostic kit (YDT465) has been designed to allow workshops to diagnose DFP3 pump faults occurring when it is possible to start the engine. This is achieved by checking the pumps under high delivery using the following procedure:

1. Fit the T-HP between the pump and rail (as shown in the diagram overleaf)

2. Use DIAMAND to run a dedicated routine in the ECU that requests a 1600 bar pressure

3. Measure back-leakage of the pump against a minimum volume (volume specific to each application. Data will be provided on a CD supplied in the kit)

4. If back leak does not reach the minimum limit, the pump can be classed as faulty

The above diagram shows the operation of the T-HP kit within the Common Rail system. The T-HP (YDT466) works by limiting the pressure through the system to 1450 bar and thus generating a certain level of back-leakage in the measurement bottle (YDT377). The actual measurement back-leakage can then be compared against the stated volume for that pump to determine whether a fault is present.

The YDT467 is a flexible high-pressure pipe suitable for use on all Delphi DFP3 applications.

As previously stated, the T-HP kit should be used for diagnostics in conjunction with the Sealed Rail kit. Workshops should also use DIAMAND to run the dedicated ECU routine required for T-HP diagnostics.

The T-HP diagnostic kit (YDT465) contains the following components:

YDT466 - T-HP with pressure limiter

YDT467 - Flexible high pressure pipe

YDT472 - Adaptor (M12 x M14)

YDT277 - Protection caps

YDT377 - 500ml back leak bottle

YDT411 - High pressure pipe (M14 x M14)

DDRX113B - CD containing manual & test data

All of the other elements required during the T-HP test (YDT269, YDT270, YDT271 & YDT423) are included within the standard Sealed Rail kit (YDT278).