Common rail injectors: bench testing and repair

A common rail injector works at over 2,000 bar and opens several times per cycle. When it fails, you feel it. Here is what types exist and how we repair them.

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[D-01·A]Types

Which injectors we repair

T-01

Solenoid

The most common. A coil opens the control valve and pressure lifts the needle.

Bosch CRI
Delphi
Denso
Typical faults: valve and nozzle

T-02

Piezo

Faster and more precise. A piezo crystal moves the valve in microseconds.

Bosch piezo
Siemens VDO / Continental
Denso piezo
Typical faults: piezo and nozzle

T-03

Unit injectors and mechanical

Pre-common-rail systems, such as VAG Pumpe-Düse (PD) unit injectors.

PD unit injectors
Mechanical injector holders
Opening-pressure setting

[D-01·B]Process

How we repair an injector

01
Incoming test
We run the injector on the bench to measure delivery, return and spray as it arrives.
02
Strip-down and cleaning
We take it apart and clean its components to see the real wear.
03
Part replacement
We replace what is worn: nozzle, valve, seals or whatever the diagnosis shows.
04
Adjustment
We adjust the injector so it delivers the right amount at every operating point again.
05
Final test
We run it on the bench again to confirm it passes before handing it back.
06
Calibration code
If your injector uses a code (IMA, QR, C2I), we give it to you to program into the ECU.

[D-01·C]References

Which injector do you have?

Check the reference engraved on the injector body and send us a photo on WhatsApp. These are the most common:

Maker	Common references	Technology
Bosch	0445110 · 0445120 · 0445115 · 0445116	Solenoid and piezo
Denso	095000 · 23670	Solenoid and piezo
Delphi	EJBR · 28xxxxxx	Solenoid
Siemens VDO / Continental	5WS40 · A2C	Piezo

Send a photo of the reference

[D-01·D]FAQ

What people ask us most

Can piezo injectors be repaired?+

In many cases, yes. The bench test tells us whether the fault is in the nozzle, the valve or the piezo stack itself, and whether a repair makes sense. If it doesn’t, we tell you.

Do I have to replace all four injectors at once?+

Not always. We test each injector separately and only repair the ones that need it. If one is badly worn, though, the rest are worth checking.

What is the calibration code?+

It is a code engraved on the injector that tells the ECU how to compensate for its small delivery differences. After the repair we give you the code to program.