Automotive Fuel System Leak Testing

Pressure decay uses gas pressure and observes pressure loss; vacuum decay observes change after evacuation. A pressure-rise approach can be relevant to a sealed system where air entering through a leak is the condition to observe. The method pages describe these approaches; they do not substitute for defining the product requirement.

The AMS intake-manifold example shows a vacuum-decay production cell with poka-yoke functions. Read the air-intake-manifold application for that specific example, then use the fixture guide to scope a different fuel or fluid component.

Use the production requirement to define a sequence: locate the part, create the intended seal, fill or evacuate the defined cavity, allow the condition to stabilize, measure, vent and communicate the result. Each step is part of the measurement system. A short cycle is useful only when the fixture and process produce a repeatable decision.

Document the nominal part condition and the variables that can change it: temperature, material response, connection geometry, internal volume and the number of cavities. The fixture guide calls out these practical inputs because an added hose, seal or manifold volume can affect the test condition. A production review should make those inputs visible rather than relying on trial-and-error settings.

Plan a representative study before releasing the station. It should include good parts, known defects or a suitable reference where available, normal operator sequence and realistic environmental conditions. The goal is to understand the station result for the defined requirement; this content does not publish a universal leak limit, cycle time, gage R&R result or standard-compliance claim.

Keep traceability decisions separate from the leak method. The cell can retain the selected program and result through its configured interfaces; see the PLC and automation integration guide for the published interface matrix and station-architecture questions.