Expert: Roland Finston - 11/11/2009

Question
I just purchased a 1994 New Yorker w/ the 3.5 at,  and on the way home, it just shut down on me.. like a motorcycle would if you were at speed, and then you hit the kill switch. I tried to restart it, and it acted like the battery was dead. we got it home I hooked it up to the charger overnight.  I tried to start it this morning and it started right up, but now I hear a bang or knock inside or around the motor. it shuts down after a coulpe min on its own, and the battery is depleted back down again.  oil level is good as is the coolant.  my line of thought is, since it drove perfectly fine before i bought it, the alternator my have had a terminal problem.  sugestions on what else?

Answer
Hi Lyle,
I would question the condition of the battery (approximate age compared to warranty, possibly a date of purchase tag on it?) and whether the charging light was 'on' while you were driving which would implicate the alternator, otherwise not.
Also, try to get any engine fault codes: turn the ignition key "on-off-on-off-on and leave on" doing that in 5 seconds or less elapase time. The watch the check engine light which remains 'on', to see if begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the count process to assure accuracy. Then group the counts in pairs in the order of appearance to form the 2-digit fault code numbers.
The write back or go to www.allpar.com/fix/codes.html for a code list.
Also listen to localize the sound source using a rubber hose as an 'ear horn'. Also check the current draw from the battery while the engine is running and when it is off using a high current range ampmeter, if you have one.
Roland