WHOA THERE KIDS! If a battery cranked a motor for 5 mins at normal speed the battery is fine! The battery DOES NOT make the engine fire, it merely turns it over to start the combustion process! If a motor is turning over at correct speed but NOT FIRING, than something in the IGNITION circuit is at fault. 3 things make a motor work; air, fuel and spark. NONE OF THEM ARE BATTERY RELATED!!! The battery is a reserve power source to TURN the motor over, NOT TO RUN IT!! Check the 3 things in the reverse of the order above to find a problem! Pull one plug wire and check for spark...is it 'hot' (deep blue and strong) or is it weak? If you have NO fire at the plugs, ck for fire at the coil. None there, ck for 12v INPUT from the ignition circuit. Nothing? Bad ignition switch probably. If you ARE getting spark, ck fuel delivery...you may have a clogged fuel filter. In any event, IF THE MOTOR IS TURNING OVER AT NORMAL SPEED THE BATTERY IS FINE!!!!! I can't tell you how many customers have come into my shop for batteries because a car wont FIRE and get p/o'd because their diagnostics were faulty! If the motor has been sitting for awhile, you may ck compression..you might have lost ring seal..if compression is down squirt a LITTLE Marvel Mystery
Oil in the cylinders, wait about 10 mins and fire it up. Sorry to rant, but this is a sore topic in the automotive business!
