Chatter Test

Chatter for new and used injectors may vary. With some used injectors, chatter is difficult to detect during slow actuation of tester lever. Some injectors may chatter louder than others. As long as there is chatter, the injector is acceptable.

1. Close tester shutoff lever at pressure gauge. Slowly depress lever and note whether chatter can be heard. If no chatter is heard, increase speed of lever movement until it reaches a point where injector chatters.
2. At fast lever movement, injector may emit a "hissing" or "squealing" sound rather than normal chatter. This is acceptable.
3. These sounds indicate that injector needle moves freely and that injector seat, guide and pintle have no mechanical defects. Replace any injector assembly which does not chatter.