1989 Lincoln Town Car ALTERNATOR OR BATTERY

Tiny
KRISTAKAPP
  • MEMBER
  • 1989 LINCOLN TOWN CAR
Electrical problem
1989 Lincoln Town Car Automatic

WITH GOOD BATTERY CHARGED THE CAR STARTS AND RUNS FOR 1/2 HOUR THEN DIES. ALTERNATOR AND BATTERY TESTED GOOD. WHEN RUNNING IF YOU DISCONNECT THE BATTERY CABLE IT DIES?
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Monday, August 23rd, 2010 AT 11:17 AM

4 Replies

Tiny
WRENCHTECH
  • EXPERT
The charging system is not working and you need to determine why.
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Monday, August 23rd, 2010 AT 11:35 AM
Tiny
KRISTAKAPP
  • MEMBER
That is what we are trying to figure out. Any ideas of where in the charging system? Where else should we look?
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Monday, August 23rd, 2010 AT 1:52 PM
Tiny
CARADIODOC
  • EXPERT
AGGHHH! Do not disconnect the battery with the engine running! That was a poor man's trick done many years ago by mechanics who didn't understand how charging systems worked or how to diagnose them. The battery is a key component in regulating system voltage. You are lucky your generator isn't working. If it was, and you raised engine speed, it is possible for the output to go to over 30 volts. Computers can not tolerate that kind of voltage and the voltage spikes that are normally dampened by the battery. While a 1989 model might not suffer irreparable harm, newer cars can have up to 47 computer modules. If enough of them are damaged, the car may be not worth repair.

The place to start is by measuring battery voltage with the engine running. You must find between 13.75 and 14.75 volts. Based on the symptoms, expect to see less than 12.6 volts verifying the dead charging system. How was your generator tested? Also, can you describe the connectors on it? Do you have a plug on the side with two fat black wires with orange stripes, or do you have a single fat black wire bolted to a terminal on the back?

Caradiodoc
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Monday, August 23rd, 2010 AT 2:45 PM
Tiny
LEE.WILKERSON
  • MEMBER
Apparently there is a wiring modification for the alternator on this car. Ask your friendly parts supplier.
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Saturday, October 30th, 2010 AT 10:18 PM

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