1989/04/03 Caterpillar

Be Sure Electrical Components Are Correctly Grounded{1408}

Usage:

3176 Truck Engines

The electronically controlled 3176 Engine makes extensive use of aluminum as a means of saving weight. Correct grounding procedures MUST be utilized. Incorrect grounding may result in an electrical component malfunction or galvanic corrosion of the aluminum components.

Single point grounding for engine and vehicle electrical systems is necessary for satisfactory performance and reliability. All electrical sensors and switches on the engine MUST be an externally grounded, two wire design. Internally grounded or case grounded sensors or switches MUST NOT be used. Illustrations 1 and 2 show single point grounds for the engine, starter-to-battery negative and chassis/vehicle frame ground.

The following components are part of the ground system on the 3176 Engine.

CYLINDERHEAD GROUND STUD: This is provided as a central grounding point for all components on the 3176 Engine. An M8X1.25-6g thread stud with washers and nut is supplied with the engine. All engine related ground wires from OEM's (original equipment manufacturers) should be attached to this stud. Follow the same procedure for early 3176 Engines that may have a fastener in this location rather than the stud. See Illustration 3.

ALTERNATOR GROUND WIRE: This is installed by Caterpillar ® to the cylinder head ground stud. The OEM should attach the free end to the alternator. This ground cable is AWG No. 2 cable and is routed to the alternator through the harness clip located on the front lifting eye. A continuity lamp (or ohmmeter) can confirm if the alternator is connected by the wire to the ground stud.

PATH TO BATTERY: Illustrations 1 and 2 show the recommended paths to the battery ground. An AWG No. 0 cable (or larger cable that is capable of carrying any possible current) must provide a ground path from the cylinder head stud location to the negative post on the battery.

Illustration 1. Cylinder head-to-battery (-) ground path.