Automotive Forums  Where Car Enthusiasts Go to Discuss Cars Online

A few weeks ago we'd had a problem on my son's Mercury Sable with it not starting due to a dying battery. So I replaced it. Everything has been fine since then. Then last night I sent him out on an errand. He drove about 8 miles to the store, with one stop (where he didn't shut off the engine). He spent 15 minutes in the store. When he came out the car wouldn't crank at all, just a click. There seems to be plenty of battery power since the lights are bright, but I tried to jump start it anyway with my RAM 1500. No amount of jump starting was able to change the symptoms or results. I'm about to head out again, in daylight, with my tools to check battery voltage to confirm my belief as well as to check fuses and some other things I found online.

What are the likely culprits and how much should I expect to pay to get this fixed?

--Chip  
--Chip

it is totally possible that the starter is bad....    i would start with disconnecting the battery cables and cleaning them at the starter relay with a wire brush...

you did not post what year....   when starter brushes go bad... it will just click... it won't engage as the starter solenoid on some years of starters are grounded through the brushes...

the small bodied starter with a solenoid on top are permanent magnet starters... tapping the cases like was done on earlier models..   usually breaks the magnets... and the parts stores will refuse to refund a core charge is dents are obvious...  

OK. More info now.

I got to the car and decided to try a start first. It started right up. The battery acted like it was less than 100% but still started on the first go. So we drove the car home and parked it. We left it alone for 5 minutes and then tried to start it. The battery acted like it was too weak, the engine cranked but didn't start and quickly got weaker. So now I'm wondering if it was the alternator all along (might explain the first bad battery too). We're charging the battery right now with a slow charger I have and we'll see how that goes. I'll also check the starter. I think the Mercury is a 98, but I'll have to check.

I'm pretty certain the problem is electrical. It might be the alternator. It shouldn't be the battery (it's only a couple of weeks old). It could be dirty contacts. The car seems to start better when it's cold then when it's hot/warm. Perhaps that's just perception.

--Chip  
--Chip

since you are charging the battery....   when you disconnect the charger... set your digital volt meter to 20 volts DC..

a fully charged battery should read 12.65 volts  after you have the head lights on for one minute.. then turn them off and measure...


12.65 volts... = 100%
12.45 volts    =  50%
12.25 volts    =  25 percent of charge...

when the engine is running and you have close to a 100 percent charged battery..

you should see between   14.1 volts.. and 14.6 volts... sometimes a little more..  never less...

if you have less...  check the belt tension...  check the belt tensioner.. that it is free to move full stroke with the belt off...  i have had others that would not move freely when the belt was off....   with the range of motion limited.. when the belt wears slightly... the belt cannot get properly tensioned..    the alternator does take over 5 horsepower to turn...  so belt tension is critical...

why would the car not start  after running for half an hour...  if the alternator is not charging.. the car is still drawing power..

the fuel pump.. about 7 amps.. the ecm... and injectors 6 to 9 amps... the ignition system.. 14 to 17 amps...  the interior fan.. yes this runs all the time the key is on.. another 5 to 10 amps..       without the alternator charging ... the battery in most cars will not start the car after about half an hour...  it may allow the car to run for an hour.. or at least till you step on the brakes... then the antilock pump can cycle on.. 30 amps... and the tail lights..  5 to 8 amps...depending on how many bulbs..



with the engine running... read the battery voltage.. with your digital volt meter...  (new digital volt meters start at 5 bucks.. and you never need to spend more than 25 on them for basic stuff)  DO NOT !!!!!  pull the battery cable off to test the charging system...   the loss of the load the battery has on the system lets the alternator build up significant voltage for a split second.. this shorts out the diodes.. and possibly many other electrical parts on the car...

post what you find...   i will be floating around today.. its pouring rain hard outside.. flash floods expected...  

OK. I tried starting the car later. It cranked briefly like it had a dying battery but didn't catch. Then it would only click. So I tried jumping it. I gave it a good long charge, read 13vDC while jumping. Still nada. Took it to a garage (had to have them pick it up). They said starter. We replaced. Now it cranks great but still not catching. They did a number of checks and the bottom line is that it now appears as if the fuel pump is bad. They say good voltage to the fuel pump but no output pressure. They checked inertia switches and the like.

So my question now is. Two failures at once? Which came first? Is there still another problem to be found? How much more am I likely to sink into the car before all is solved? This is an older car, a third vehicle so the kid can commute to college. I'd really not like to break the bank to fix it. The starter was ~$530. The first guess last night on the fuel pump was probably in the $600 neighborhood (he's supposed to call this morning with an estimate).

Thanks for the help.  
--Chip

just to get it home....

have someone pound on the bottom of the gas tank.. while someone else cranks the engine... that will most of the time  get the fuel pump to spin...  this works about 90 percent of the time...


it is totally possible that both have gone bad at the same time..  

So know we're having the same problem again. What are the chances we'd have the same problem with the starter twice within a year after having the first replaced. I am really anxious to be able to dump this piece of junk. It's been nothing but a headache.  
--Chip

do you have a digital volt meter...


do a voltage drop test... takes about 5 minutes..

set meter to 20 volts DC...

1.  test from the negative battery post to the engine block...

have someone crank the engine...   you should see less than 0.5 volts while the engine is cranking..


2..  turn on  the headlights... turn on the ignition switch..

test from the negative battery post to the body...

a reading of 0.02 volts is expected...

log in... check your messages to the left of where you log out at...