caterpillar For CAT Caterpillar 3406 Fuel Injection Line Kit 6 Pcs 1917941 1917942 1917943 Posted on December 16, 2023 by admin 1 qty – #1 Fuel Line (OE # 7C3421, 4P9661, 1917941, 4P3921). 1 qty – #2 Fuel Line (OE # 7C3422, 4P9662, 1917942, 4P3922). 1 qty – #3 Fuel Line (OE # 7C3423, 4P9663, 1917943, 4P3923). Perfect Compatibility? This item fits a wide range of Caterpillar engines. caterpillar fuel injection line