How to Disable the Car from Starting You will need to know this for several test Compression testing Starting tests Etc.

Older cars with external coil Disconnect battery power to the positive coil terminal. This prevents the coil from activating secondary ignition.

Older cars with external coils pic

GM With External Coil Remove the wires to the Coil.

External Coils Some of the other cars just find the coil and disconnect it.

Toyota

GM HEI On GM HEI disconnect the wire going into the Cap

GM HEI

Conventional Distributor Cap On vehicles with a conventional distributor cap, remove the coil lead from the top of the distributor cap and ground it. Caution: Failure to properly ground the wire may result in damage to the system.

EFI On some computer- controlled vehicles equipped with fuel injection, hold the throttle wide open while cranking the engine. The fuel injection system automatically disables itself because it assumes that the engine is flooded. If engine starts at first, shut it “off” and crank again, keeping the throttle wide open. General Motors cars do this.

EFI On a vehicle with throttle body injection (TBI) or central fuel injection (CFI) disconnect the fuel injector. This will disable fuel flow.

EFI On newer cars you can disconnect the CKP (Crank Shaft Position Sensor) that will disable the fuel and ignition. Look up the location of the CKP in Alldata or Mitchell.

EFI Remove the power to the fuel pump to disable fuel flow on any vehicle with electronic fuel injection (EFI) On some cars you will have to pull a fuse or pull a relay to disconnect the power to the fuel pump.

Inertia switch Fords This switch, is used on all vehicles with electric fuel pumps. This switch shuts off the fuel pump in the event of an accident. The switch consists of a steel ball held in place by a magnet. Upon sharp impact, the ball breaks loose from the magnet, rolls up a conical ramp, and strikes a target plate that opens the switch electrical contacts and shuts off the fuel pump. Once the switch is open, it must be manually reset before starting the vehicle. Thanks to Alldata For Picture and text

Inertia switch

DTC’s NOTE: If any DTC’s are stored, clear and ignore them. DTC - Diagnostic Trouble Codes - An electronic signal stored in an automotive computer, indicating the presence of a fault detected by that computer.

The End