Look on the injector itself. Most diesel injectors carry their part number laser-etched, stamped or printed on the body, often near the electrical connector, on the upper body below the fuel inlet, or on the flange of a mechanical nozzle holder. You may have to clean away oil and carbon gently to read it, and on some engines you’ll only see it once the injector is out.
The number on the injector is the one that matters. A parts lookup by year and model is a good starting point, but it can’t tell you whether your engine received a running change, a previous replacement or an injector from a different calibration.
What you’ll find on the injector
Many injectors carry more than one set of characters. Record all of them.
- The injector maker’s part number identifies the design and calibration.
- The engine maker’s part number, sometimes on the same body or a label, identifies the part in the engine manufacturer’s catalog.
- A trim, correction or calibration code on many common-rail injectors. This isn’t a part number. It describes how that individual injector performed when tested and is programmed into the engine computer. See diesel injector coding.
- A serial number or date code unique to that injector.
By manufacturer
Bosch common-rail injectors. Bosch common-rail injector part numbers begin with 0 445 1, followed by more digits. Look on the injector body, typically on the upper portion near the connector.
Bosch mechanical nozzles and holders. Nozzles often carry a type code beginning with letters such as DLLA or DSLA, which describes the nozzle’s construction. Holders carry their own number.
Denso common-rail injectors. Denso injector numbers commonly appear in forms such as 095000-xxxx or 295050-xxxx, often alongside the vehicle maker’s number. Many Denso injectors also carry a QR code used for correction data.
Delphi injectors. Delphi light-duty common-rail injectors often carry numbers beginning with EJBR. Delphi heavy-duty unit injectors, such as those on Volvo D13 and Mack MP8 engines, are usually identified by the engine maker’s part number as well as Delphi’s.
Ford 7.3 Power Stroke HEUI injectors. These carry a two-letter code that identifies the injector type and application, such as AA, AB, AD or AE. The code matters: some are single-shot and some are split-shot, and some 1999–2003 trucks use a different injector in cylinder 8, so record each code by cylinder.
Caterpillar, Cummins and Detroit injectors. Heavy-duty injectors typically carry the engine maker’s part number, and remanufactured units may carry a separate reman number. Record both if present.
Superseded numbers
Injector designs get updated. A superseding number may replace your original in the catalog, sometimes with improvements. That’s normal, but it’s one more reason to start with the number on your injector: it gives the supplier a reference point from which to confirm the correct current replacement.
Mixed sets are more common than you’d think
If an engine has had injectors replaced individually over the years, you may find different numbers or different makers’ reman units in the same engine. Note which cylinder each came from. That history matters when diagnosing balance problems, and it matters when deciding whether to replace a set.
Tips for reading worn markings
- Wipe the area with a clean rag and a mild cleaner. Avoid wire brushes and abrasives, which can erase laser etching.
- Use a flashlight held at a low angle to bring up shallow characters.
- Photograph the marking with your phone and zoom in.
- If the number is unreadable on one injector, the others in the set may be legible and identical.
When you can’t find a number
Record the engine make, model and serial number, the vehicle VIN or equipment serial number and any engine data plate information, such as the CPL number on Cummins engines. Photograph the injector from several angles, including the connector and nozzle tip. A specialist can often identify the injector from those details, though testing may be needed to confirm its calibration.
Further technical reference: Bosch Aftermarket: diesel test benches and tools. Use the exact engine/injector/pump service information for applicable procedures and limits.
Send the numbers before the parts
Diesel Control Technicians works with injectors from all the major manufacturers. Send DCT the numbers from your injectors, with photos if they’re hard to read, and the engine details. We’ll help confirm what you have and the service options for it before you ship. For a full walkthrough of the process, see how mail-in diesel fuel injection repair works.
Discuss injector testing: Request a mail-in component review with the complete injector number, original cylinder, symptoms and any existing measurements. Confirm the supported test and repair path before removal or shipment.