760 L4-2320cc 2.3L SOHC Turbo B23FT (1984)
Wastegate: Description and Operation
Fig. 2 Turbo Control Components
Several devices are used to allow the engine to use relatively high boost pressures at mid-range Rpm without being overboosted at higher Rpm, Fig. 2.
A wastegate that begins to open at 6 psi to prevent excessive boost pressure is used. If the wastegate fails, an overload protection switch that senses boost
pressure in the intake manifold opens the fuel pump relay ground circuit at 10 psi boost. This momentarily stops the fuel and engine to reduce boost
pressure.
In order to enrich the air fuel mixture under acceleration, a pressure switch mounted on the firewall closes at 2.9 psi boost pressure. This switches the
oxygen sensor feedback system to a fixed cycle of 58.5° (when measured on a high quality dwell meter) to provide the needed enrichment. Finally, the
distributor is equipped with a vacuum advance/boost retard unit that advances timing up to 15° under light load conditions and retards timing up to 8° at
a boost pressure of 5 psi.