ZR1 Full Power Issue

[Paul Workman]

FYI, this is the vacuum circuit for the secondaries (see FSM). This diagram is from a 90, and the "SWITCH, DIFFERENTIAL PRESSURE" is attached under the ECM bracket. But, the switch is located UNDER the plenum on 91-95s.

NOTE: Normally, the vacuum reserve canister is charged by plenum vacuum when the engine runs. The vacuum pump & reservoir supplies vacuum to hold the secondaries open when vacuum drops at WOT.

However, if one chooses to delete the secondary vacuum system all together (as many have - running with the secondary throttle plates fixed open or removed entirely) you need not worry about any of that secondary headache and run on FULL ENGINE POWER 100% of the time (except at idle only).