Tech Tip: Diagnosing a Slow Cranking Starter or No Crank at All
A slow cranking starter or no crank at all may be caused by a faulty ground that prevents full voltage to the starter motor. Most people assume the starter is grounded because it is bolted to the engine. However, that does not mean it’s grounded properly. The combination of road dirt, salt corrosion, engine heat and vehicle age can prevent a good starter-to-engine ground (metal-to-metal contact).
Tech Tip: Diagnosing a Crunch or Popping Sound During Low-Speed Turning
Some vehicle owners may experience a crunch and/or popping sound during low-speed turning. This can be caused by the lower control arm striking the steering knuckle during full-turn type maneuvers, causing the crunch sound. Slight movement between the steering gear attaching bolt threads and the frame rail inboard steering gear attaching holes may cause the popping sound.
Tech Tip: Diagnosing a Sinking, Low or Spongy Brake Pedal
To diagnose a sinking, low or spongy brake pedal, begin by isolating the master cylinder. Remove the lines from the master cylinder and insert blocking plugs into the ports. Press on the brake pedal. If the pedal is firm and hard, the master cylinder is good. If the pedal still drops, either air is in the unit or it is bypassing internally. Bleed the unit or replace as necessary. Reconnect and bleed the system.
Tech Tip: Restore Driveability and Performance after Power Disconnect
Many computer-controlled vehicles memorize and store operation patterns that are lost when battery power is disconnected. The computer will use default data until a number of drive cycles have been memorized. To correct this problem the computer must go through a relearn procedure after the battery is disconnected. For the specific relearn procedures, refer to OE service bulletins or a repair manual for your vehicle. If a specific relearn procedure is not available, the following procedure can be used.
Tech Tip: When to Change the Automatic Drive Belt Tensioner
While CARDONE water pumps, alternators, smog pumps and power steering pumps all do different jobs, they all have one thing in common: they are belt-driven. Without a properly functioning belt-drive system, these units can’t work as designed. Most late-model vehicles use an automatic belt-tensioning device of some design.
Tech Tip: Nissan Optical Distributor Test
Many Nissan vehicles have a power transistor controlling the coil (or igniter). The power transistor is a separate unit on optical distributors. It allows the signal sent from the ECU (low current) to activate the primary circuit in the ignition coil (higher current). This induces high voltage in the secondary windings of the coil, providing spark to the distributor cap and plugs.
Tech Tip: Radio Hum or Whine Continues After Replacing the Alternator
After replacing the alternator, a hum, whine or buzzing noise is heard through the speakers of the vehicle radio or two-way radio when the fuel pump runs. The in-tank electric fuel pump may be the cause of the electrical noise. In August of 2002, Ford Motor issued TSB 02-16-4 addressing this issue.
Tech Tip: Excessive Starter Voltage Drop Prevents Proper Operation
Most people assume the starter is grounded because it is bolted to the engine. However, that does not mean it’s grounded properly. The combination of road dirt, salt corrosion, engine heat and vehicle age can prevent a good starter-to-engine ground (metal-to-metal contact). A good ground path should measure zero voltage loss (no voltage drop).
Tech Tip: GM Power Steering Gear Pop or Crunch Noise
Some GM vehicle owners may experience a crunch and/or popping sound during low-speed turning. This condition is caused because the lower control arm may be striking the steering knuckle during full-turn type maneuvers, causing the crunch sound. Slight movement between the steering gear attaching bolt threads and the frame rail inboard steering gear attaching holes may cause the popping sound.
Tech Tip: Is Caliper Replacement a Wheel of Fortune or Does it Sometimes Cost a Fortune?
Have you ever looked for something in the shop only to be frustrated when someone else comes by (usually the boss) and reveals the item right before your eyes?