Grounding the Electrical System
Block Grounding
One of the leading causes of abnormal ignition and gauge problems is a bad or improper ground. Just because the negative cable is ran from the battery to the frame doesn't mean the engine is getting that ground. The starter, alternator, and most distributors are grounded through the engine block. If you have rubber, polyurethane, or painted motor mounts and no ground strap, you may not have a sufficient ground supplied to these electrical components.
Common symptoms caused by an improper ground
- The engine missfires at a high RPM
- The tachometer reads erratically
- The engine cranks slowly
- You've tried a known good ignition and the problem still exists
The fix is simple!
Make sure to run a battery cable from the battery to the frame and a ground strap from the engine block to the frame. The battery cable should at least be the same gauge size as the starter since it will supply the ground to it. Also make sure the distributor hold down clamp and bolt are not painted to ensure you have a good connection between the block and the distributor. For good measure you might consider adding a ground strap from the frame to the body of the car.
