Hi there Customer (name blocked for privacy),

It sounds to me like something is wrong with either the battery or charging system. When you charged the battery that day and left it sit overnight, was it still connected to the car or not? If it was, sounds like you might have another electrical problem. If not, might be a bad battery. In any case, you can take the car to most parts stores (if it will make it that far) and they will be able to test your battery and alternator usually for free.

Could have a parasitic drain somewhere.. These are sometimes hard to figure out. Have you had made any changes to your car lately (changed radios, CB, radar detector, cell phone charger)... If not, it may take awhile... But you could try charging the battery disconnected from the vehicle, and see if it will last overnight. If it does, good. Then hook it up to your car, and pull a couple fuses (keeping track of which ones you have pulled).. See if it will hold charge. If it does, put the fuses back in. See if it will hold charge. If not, remove half of what you did before, see if it will hold charge, and so on.. You should be able to narrow it down to which circuit is draining the battery that way and go from there. Also, if your battery has caps on them, pull them off and check the water level. They should be about 1/8" from the top or, the bottom of the plastic tube that goes down. If it's a maintenance free battery check to see if it has a clear indicator window usually circular a little smaller than a dime. Make sure you have good light on it and see if it is green. If it is not, the battery is dead. Hope this helps.

-James

Hi Customer (name blocked for privacy),

I think you are on the right track. Here is some information I've got on your vehicle's distributor and testing...

Description And Operation

The General Motors HEI system is a pulse-triggered, transistorized controlled, inductive discharge ignition system. The entire HEI system (except for the ignition coil) is contained within the distributor cap.

The distributor, in addition to housing the mechanical and vacuum advance mechanisms, contains the electronic control module, and the magnetic triggering device. The magnetic pick-up assembly contains a permanent magnet, a pole piece with internal teeth, and a pick-up coil (not to be confused with the ignition coil).

In the HEI system, as in other electronic ignition systems, the breaker points have been replaced with an electronic switch — a transistor — which is located within the control module. This switching transistor performs the same function the points did in an conventional ignition system. It simply turns coil primary current on and off at the correct time. Essentially then, electronic and conventional ignition systems operate on the same principle.

The module which houses the switching transistor is controlled (turned on and off) by a magnetically generated impulse induced in the pick-up coil. When the teeth of the rotating timer align with the teeth of the pole piece, the induced voltage in the pick-up coil signals the electronic module to open the coil primary circuit. The primary current then decreases, and a high voltage is induced in the ignition coil secondary windings which is then directed through the rotor and high voltage leads (spark plug wires) to fire the spark plugs.

In essence then, the pick-up coil module system simply replaces the conventional breaker points and condenser. The condenser found within the distributor is for radio suppression purposes only and has nothing to do with the ignition process. The module automatically controls the dwell period, increasing it with increasing engine speed. Since dwell is automatically controlled, it cannot be adjusted. The module itself is non-adjustable and non-repairable and must be replaced if found defective.

HEI SYSTEM PRECAUTIONS

Before going on to troubleshooting, it might be a good idea to take note of the following precautions:

Timing Light Use

Inductive pick-up timing lights are the best kind to use if your truck is equipped with HEI. Timing lights which connect between the spark plug and the spark plug wire occasionally (not always) give false readings.

Spark Plug Wires

The plug wires used with HEI systems are of a different construction than conventional wires. When replacing them, make sure you get the correct wires, since conventional wires won't carry the voltage. Also, handle them carefully to avoid cracking or splitting them and never pierce them.

Tachometer Use

Not all tachometers will operate or indicate correctly when used on a HEI system. While some tachometers may give a reading, this does not necessarily mean the reading is correct. In addition, some tachometers hook up differently from others. If you can't figure out whether or not your tachometer will work on your truck, check with the tachometer manufacturer.

HEI Systems Testers

Instruments designed specifically for testing HEI systems are available from several tool manufacturers. Some of these will even test the module itself. However, the tests given in the following section will require only an ohmmeter and a voltmeter.

Diagnosis and Testing

The symptoms of a defective component within the HEI system are exactly the same as those you would encounter in a conventional system. Some of these symptoms are:

• Hard or no Starting
• Rough Idle
• Fuel Poor Economy
• Engine misses under load or while accelerating

If you suspect a problem in the ignition system, there are certain preliminary checks which you should carry out before you begin to check the electronic portions of the system. First, it is extremely important to make sure the vehicle battery is in a good state of charge. A defective or poorly charged battery will cause the various components of the ignition system to read incorrectly when they are being tested. Second, make sure all wiring connections are clean and tight, not only at the battery, but also at the distributor cap, ignition coil, and at the electronic control module.

SECONDARY SPARK TEST

Since the only change between electronic and conventional ignition systems is in the distributor component area, it is imperative to check the secondary ignition circuit first. If the secondary circuit checks out properly, then the engine condition is probably not the fault of the ignition system. To check the secondary ignition system, perform a simple spark test.

1. Remove one of the plug wires and insert some sort of extension in the plug socket. An old spark plug with the ground electrode removed makes a good extension.
2. Hold the wire and extension about ¹⁄₄ in. (.009mm) away from the block and crank the engine. If a normal spark occurs, then the problem is most likely not in the ignition system.
3. Check for fuel system problems, or fouled spark plugs.
4. If, however, there is no spark or a weak spark, then further ignition system testing will have to be done. Troubleshooting techniques fall into two categories, depending on the nature of the problem. The categories are (1) Engine cranks, but won't start or (2) Engine runs, but runs rough or cuts out.

Engine Fails to Start

1. If the engine won't start, perform a spark test as described earlier. If no spark occurs, check for the presence of normal battery voltage at the battery ( BAT) terminal in the distributor cap. The ignition switch must be in the ON position for this test.
2. If battery voltage is not present, this indicates an open circuit in the ignition primary wiring leading to the distributor. In this case, you will have to check wiring continuity back to the ignition switch using a test light.
3. If there is battery voltage at the BAT terminal, but no spark at the plugs, then the problem lies within the distributor assembly. Go on to test the ignition coil.

Engine Runs, but Runs Roughly or Cuts Out

1. Make sure the plug wires are in good shape first. There should be no obvious cracks or breaks. You can check the plug wires with an ohmmeter, but do not pierce the wires with a probe.
2. If the plug wires are OK, remove the cap assembly, and check for moisture, cracks, chips, or carbon tracks, or any other high voltage leaks or failures.
3. Replace the cap if you find any defects. Make sure the timer wheel rotates when the engine is cranked. If everything is all right so far, go on to test the ignition coil.

IGNITION COIL

Carbureted Engines

1. Connect an ohmmeter between the TACH and BAT terminals in the distributor cap. The primary coil resistance should be less than one ohm (zero or nearly zero).
2. To check the coil secondary resistance, connect an ohmmeter between the rotor button and the BAT terminal. Then connect the ohmmeter between the ground terminal and the rotor button. The resistance in both cases should be between 6000 and 30,000 ohms.
3. Replace the coil only if the readings in Step 1 and 2 are infinite.

   NOTE: These resistance checks will not disclose shorted coil windings. This condition can be detected only with scope analysis or a suitably designed coil tester. If these instruments are unavailable, replace the coil with a known good coil as a final coil test.

Fuel Injected Engines

1. Tag and disconnect the distributor lead and wiring from the coil.
2. Connect an ohmmeter as shown in Step 1 of the accompanying illustration. Place the ohmmeter on the high scale. The reading should be infinite.
   < cellSpacing=0 cellPadding=0 wid=400> <> < align=middle>Fig. 1: Fuel injected engine ignition coil test

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3. Connect an ohmmeter as shown in Step 2 of the same illustration. Place the ohmmeter on the low scale. The reading should be very low or zero. If not replace the coil.
4. Connect an ohmmeter as shown in Step 3 of the same illustration. Place the ohmmeter on the high scale. The meter should not read infinite. If it does replace the coil.
5. Connect the distributor lead and wiring.

PICK-UP COIL

1. To test the pick-up coil, first disconnect the white and green module leads. Set the ohmmeter on the high scale and connect it between a ground and either the white or green lead. Any resistance measurement less than infinity requires replacement of the pick-up coil.
   < cellSpacing=0 cellPadding=0 wid=400> <> < align=middle>Fig. 1: The pick-up coil is located inside the distributor

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   < cellSpacing=0 cellPadding=0 wid=400> <> < align=middle>Fig. 2: Testing the pick-up coil — coil-in-cap

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   < cellSpacing=0 cellPadding=0 wid=400> <> < align=middle>Fig. 3: Testing the pick-up coil — separate coil

   Images available only to Customers.
   
   

2. Pick-up coil continuity is tested by connecting the ohmmeter (on low range) between the white and green leads. Normal resistance is between 500 and 1500 ohms. Move the vacuum advance arm while performing this test. This will detect any break in coil continuity. Such a condition can cause intermittent misfiring. Replace the pick-up coil if the reading is outside the specified limits.
3. If no defects have been found at this time, and you still have a problem, then the module will have to be checked. If you do not have access to a module tester, the only possible alternative is a substitution test. If the module fails the substitution test, replace it.

I hope this is enough to get you going... Let me know if you need more help okay?

-James