You're guessing all over the place. First of all, due to the many computers' memory circuits, the battery can only be counted on to start the engine after sitting for three weeks, if it's a fairly new one. Older batteries don't last that long. Second, it is REAL common to have poor contact with the jumper cables making them ineffective. I watch the head lights or dome lights on the car with the dead battery. You'll see them brighten just a little after wiggling the jumper cable clamps until they make good contact. Once the lights brighten, let the battery charge a while before trying to crank the engine.
Be aware that dead batteries will not start to charge right away. It takes about 10 - 15 minutes for the acid to become conductive, THEN it will start to recharge. If you use a battery charger instead of jumper cables, charge it at the lowest rate for at least an hour, then measure it's voltage. Fully-charged it should read 12.6 volts. If you find 12.2 volts, it's good but still discharged. If it's closer to 11 volts, it has a shorted cell and must be replaced.
Once you get the engine started, it is likely not going to stay running unless you hold the gas pedal down 1/8". The Engine Computer lost its memory and has to relearn "minimum throttle" before it will know when it must be in control of idle speed. It also might not give you the normal "idle flare-up" to 1500 rpm when you start the engine. To meet the conditions for the relearn to take place, drive at highway speed with the engine warmed up, then coast for at least seven seconds without touching the brake or gas pedals.
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Monday, October 29th, 2012 AT 3:49 AM