Cold Engine Control Pressure Test
- Install valve between pressure gauge and control pressure regulator. See TEST EQUIPMENT HOOK-UP in this article. Hang gauge from convenient point above level of units to be tested.
- Unplug electrical connector at auxiliary air regulator to avoid overheating unit. Unplug connector at mixture control unit. Turn ignition on. Open 2-way valve for flow-through operation and check fuel pressure. See Fig 1.
- If fuel pressure reads too low, warm-up regulator is defective and should be replaced. If fuel pressure reads too high, regulator is defective of fuel return flow is insufficient of restricted. Turn ignition off.