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Author Topic: Electrical: Charging and Starting Problems  (Read 20478 times)

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Reggie

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Electrical: Charging and Starting Problems
« on: February 19, 2008, 17:45:19 »

Causes of Charging and Starting System Problems

Note: Dirty or corroded contacts cause more starting and charging problems than anything else. Dirty contacts will slowly drain a battery - even a brand new one. Things to check if your car is not charging or starting properly:

Slow or No Starting

  • Engine will not crank (turn over)
    • Battery cables.  Battery cables must be clean and tight.  If the ends on the cables have been replaced, THROW THE CABLES AWAY and get new cables. DO NOT try using replacement cable ends.  They are junk, and they are a problem waiting to happen. Most auto parts houses sell inexpensive battery cable cleaning tools with male and female wire brush ends. When you get the cable cleaner, you should also pick up a set of felt "anti-corrosion" pads. A package usually contains two felt washer shaped pads that go over the battery terminals before installing the battery cables.  Each pad contains a chemical that helps to prevent corrosion.  You can also spray a light coat of lithium or equivalent grease, or Permatex dielectric grease on the post after you attach the cable to the battery terminal. DO NOT put grease on the terminal contact surfaces.
    • Quick disconnector on the positive battery cable. This spot can corrode and break contact when put under any kind of load. Problems with the quick disconnector have been known to cause the entire car to shut down - sometimes, even while driving.
    • Loose or dirty starter contacts. Starter contacts must be clean and tight.  Clean contacts with a fine wire brush. Always disconnect the positive battery cable first before cleaning starter contacts.
    • Dead battery.  The battery could be discharged enough to cause the car not to start.
    • Defective (bad) battery. Sometimes, a battery can have a bad cell that works fine except when under a load.  Have the battery load tested to be sure.
    • Engine to body ground strap.  These must be clean and tight since the engine itself sits on rubber mounts and does NOT ground to the body/chassis.  There are at least two of them and possibly three.  One runs from the back of the passenger side of the engine to the firewall. The other one is part of the negative battery cable, and bolts to the front of the engine on the driver's side. Some models may have an additional strap running from the passenger side of the transmission to the underside of the frame rail.
    • Bad starter Relay
    • Bad starter
    • Loose or bad connection to neutral safety switch, or bad neutral safety switch. The starter relay (located on the driver's side of the firewall), must receive a ground signal from the transmission neutral safety switch to allow the starting system to work. The engine will not turn over at all if there is a problem.
  • Engine cranks slowly or just makes a ticking sound
    • Battery cables. (see above)
    • Loose or dirty starter contacts. (see above)
    • Low (discharged) battery.  The battery could be discharged enough to cause the car to crank slowly.
    • Defective (bad) battery. (see above).
    • Engine to body ground strap. (see above).
    • Bad starter

Undercharging

  • Battery cables.  (see above).
  • Quick disconnector on the positive battery cable. (see above).
  • Loose alternator belt.
  • Loose or corroded connections at the alternator.
  • Loose or corroded connections at the terminal block.
  • Loose or corroded chassis to ground cable. Make sure that the frame connection for the negative cable is clean. Remove it and hit the cable end and the frame location with a fine wire brush.
  • Engine to body ground strap.  See above under "Slow or No Starting".
  • Alternator ground. The alternator housing must be properly grounded to charge the battery, so make sure that the mounting bolts are tight. NOTE: Heavy duty cop car alternators have a separate ground wire which must be clean and tight.
  • Broken wires or bad contacts leading to the voltage regulator.
  • Voltage regulator not grounded properly. Remove it, hit the firewall and back of the regulator with a fine wire brush and reinstall it.
  • Loose or corroded connections at bulkhead disconnect (at firewall).
  • Bad voltage regulator.
  • Bad Alternator.
  • Defective (bad) battery.
  • Also check for signs of previous repairs anywhere in the charging system.  Unsoldered or improperly soldered repairs can cause charging problems.

Overcharging

  • Grounded alternator field wire, field terminals or connections.
  • Alternator field grounded internally - probably a bad alternator requiring a bench test.
  • Voltage regulator sensing circuit open.
  • Broken wires or bad contacts leading to the voltage regulator.
  • Also check for signs of previous repairs anywhere in the charging system.  Unsoldered or improperly soldered repairs can cause charging problems.

With any of the above conditions, always check the easy stuff first.   Also, if you decide to take your car to a garage to check out the system, make sure that you clean ALL contacts very well first.

Voltage Chart

Using a DC voltmeter with your engine running and your charging system working properly, you should get voltage readings in the ranges listed for the ambient temperatures below:

Ambient Temperature Near       Voltage Range
Voltage Regulator       
-30*C or -20*F       14.9 to 15.8
27*C or 80*F       13.9 to 14.4
60*C or 140*F       13.0 to 13.7
Above 60*C or above 140*F       Less than 13.60

Batteries

A car battery is designed with thin plates for extra surface area.  The extra surface area provides a very large amount of current for a short period of time to crank the engine during starting. After the engine starts, the alternator takes over to provide all of the power that the car needs.  The battery no longer provides power, and just goes along for the ride. A car with a properly functioning charging system can be driven indefinitely with the battery removed. Typically, a quality car battery can last for several years as long as it is not regularly discharged by a significant amount.

GENERAL WARNING ABOUT CAR BATTERIES:

  • BATTERIES CAN EXPLODE AND CAUSE SERIOUS INJURY, INCLUDING BLINDNESS.
  • WORK IN A WELL-VENTILATED AREA.
  • DO NOT smoke, or have any type of flame or sparks around a car battery.
  • BATTERIES CONTAIN SULFURIC ACID
    • SULFURIC ACID CAN CAUSE SEVERE SKIN BURNS.
    • SULFURIC ACID IS ALSO VERY CORROSIVE TO ANYTHING IT COMES IN CONTACT WITH, INCLUDING METAL, WOOD AND FABRIC.
  • ALWAYS disconnect the negative cable first, and then disconnect the positive cable.
  • DO NOT lay tools on the battery. Tools can make contact with both terminals, causing sparks and a possible explosion.
  • DO NOT lay the battery on its side.
  • When loosening and tightening a battery cable, support the cable end with one hand to prevent the wrench from breaking the battery terminal. Apply pressure in the opposite direction of the wrench.  If you are loosening a cable, apply an equal amount of downward pressure on the cable end with your free hand.  If you are tightening a cable, apply an equal amount of upward pressure on the cable end with your free hand. You can also use a battery terminal puller.
  • If a battery terminal can be moved, it is broken and the battery should be recycled.
  • RECYCLE old batteries. DO NOT throw them in the trash.  Sulfuric acid is highly toxic, and can cause severe injuries to anyone who unknowingly handles a discarded battery improperly.
  • It is a good idea to wear safety glasses and use latex work gloves when working on batteries.

Battery Selection

The following battery specifications are recommended for M-bodies by Chrysler Corporation:

Application   Load Test  CCA *   
RC *
Standard  200 Amps  400 Amps  100 Min.
Heavy Duty  250 Amps  500 Amps  110 Min.

  • * CCA (Cold Crankings Amps):  CCA is measured as the current that a battery can deliver for 30 seconds at 0 degrees F (or -18 degrees C) while maintaining an operating level of at least 7.2 volts (1.2 volts per cell).  DO NOT buy a battery with a CCA rating below the recommended specifications above.  Also don't buy anything with a CCA rating over 200 amps higher than the Heavy Duty rating above.  It is usually not worth the extra cost to go any higher.
  • * RC  (Reserve Capacity). RC is the length of time that a battery can deliver 25 amps and maintain a minimum terminal voltage of 10.5 volts at 80 degrees F (or 27 degrees C). In other words, it's battery "staying power."  Try to find a battery with the longest RC that you can find.  It might allow you to limp home if your charging system fails.
  • Date Codes: Batteries usually have a date code that will tell you when it was manufactured.  Buy the freshest battery that you can find and avoid any battery that is more than six months old.
  • Warranties: Batteries will usually have a total warranty period and a free replacement period.  After the free replacement period, the replacement cost for a failed battery is prorated to increase the longer that you have owned the battery.  Try to get a battery with the longest free replacement period, as well as a good warranty period.
  • Inexpensive Batteries: Cheap batteries are a waste of time and money. Buy a quality, name brand battery and you will thank yourself later.  The cheap off-brand batteries that you find will not last as long. The old adage; "You get what you pay for.." is very true when it comes to car batteries.
  • Deep cycle Batteries: Deep cycle batteries are typically used in RVs, boats, golf carts and even solar power systems.  Like regular car batteries, deep cycle batteries are lead-acid batteries, except that they have much thicker plates. Deep cycle batteries are designed to provide a steady amount of current over a long period of time. They are not designed to provide the instant power surge that a car battery can. The thicker plates of a deep cycle battery allow it to be deeply discharged over and over again, which would quickly ruin a regular car battery. Typically, a deep cycle battery will have two or three times the RC of a car battery, but it will only deliver one-half or three-quarters the CCAs. In addition, a deep cycle battery can withstand several hundred total discharge/recharge cycles, while a car battery is not designed to be totally discharged.  If you decide to use a deep cycle battery for any reason, make sure that it meets AT LEAST the minimum CCA and RC ratings listed above as recommended for M-bodies by Chrysler Corporation.   NOTE: A deep cycle battery is NOT the answer to a charging system problem.  It just treats the symptom and doesn't correct the problem.    If your car is not charging properly, a deep cycle battery might last longer than a regular battery, but it will eventually fail.  Chrysler has been building these cars for years, and if a deep cycle battery was needed for a proper charging system, they would have used them.  Identify and correct the problem and the system will charge properly.

Source:
 
« Last Edit: June 20, 2009, 09:39:15 by Reggie »
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