The VW CAY 1.6 TDI family uses a 1,598cc four-cylinder, 16-valve common-rail diesel with an intercooler, EGR and, in most applications, a DPF. The quoted bore and stroke are 79.5 × 80.5mm and the compression ratio is approximately 16.5:1.
Factory variants listed here are CAYA 75PS/195Nm, CAYB 90PS/230Nm, CAYC 105PS/250Nm, CAYD 102PS/250Nm and CAYE 75PS/around 225Nm, depending on application. Confirm the engine code and vehicle specification before using these figures for a particular car.
Applications include VW Polo, Golf, Golf Plus, Jetta, Touran, Passat and Caddy; Audi A1 and A3; SEAT Ibiza, Leon and Altea; and Skoda Fabia, Octavia, Rapid, Roomster and Superb.
The fuel system uses piezo common-rail injectors. The quoted low-pressure supply is around 5 bar, with rail pressure up to around 1,600 bar. Siemens/VDO injector identifiers include 03L130277B and A2C9626040080; part-number compatibility needs checking against the vehicle.
Injector faults can be electrical as well as mechanical. Hard starting, rough running, poor cylinder contribution, smoke, limp mode or an injector-circuit code require checks of the injector, wiring and ECU driver rather than immediate parts replacement. Poor combustion can also contribute to soot loading and DPF problems.
We can investigate the vehicle, assess supported injectors and test the ECU control side where indicated. Send the part numbers before removing injectors for bench work. Replacement requires the appropriate correction code in the ECU, renewed sealing components and the specified fitting procedure.
Resolve injector, EGR, DPF or other running faults before tuning. A performance calibration cannot repair an electrically failing injector or compensate for a damaged fuel system.
