1990 740 Turbo - Charged battery outside car, now car won't start

[Skonnie]

Ohdeargodpleasehelpme, I recently charged a relatively new battery,
reinstalled it correctly, and now can't get the engine or starter to
turn over. Power windows, locks, lights all work, but no discernable
sound comes from the car, save for a slight clicking. My thinking is
that I have unwittingly "reset" some of the sensors, or some such
thing. I just bought the car ($700, so there was bound to be problems)
and am unsure of the condition of the alternator. The battery drained
quickly after I bought it, but it might be due to several hours of
cleaning and having the doorlights on. Any advice, particularly of the
DIY variety would be greatly appreciated.

 

[zencraps]

Ohdeargodpleasehelpme, I recently charged a relatively new battery,
reinstalled it correctly, and now can't get the engine or starter to
turn over. Power windows, locks, lights all work, but no discernable
sound comes from the car, save for a slight clicking. My thinking is
that I have unwittingly "reset" some of the sensors, or some such
thing. I just bought the car ($700, so there was bound to be problems)
and am unsure of the condition of the alternator. The battery drained
quickly after I bought it, but it might be due to several hours of
cleaning and having the doorlights on. Any advice, particularly of the
DIY variety would be greatly appreciated.

 

[zencraps]

Are the cables neat and clean, especially where they hook on to the
battery terminals?

Is the battery in fact "good?" Perhaps it has a bad cell, and can't
put out enough power to turn over the engine, although there is enough
to run the accessories.

The fact that you hear a "click" would imply you are getting power to
the solenoid, so the starting circuit is OK.

If the cables are clean, the battery is good, the problem is most
likely with the starter / starter solenoid or its connections.

 

[Michael Pardee]

Ohdeargodpleasehelpme, I recently charged a relatively new battery,
reinstalled it correctly, and now can't get the engine or starter to
turn over. Power windows, locks, lights all work, but no discernable
sound comes from the car, save for a slight clicking. My thinking is
that I have unwittingly "reset" some of the sensors, or some such
thing. I just bought the car ($700, so there was bound to be problems)
and am unsure of the condition of the alternator. The battery drained
quickly after I bought it, but it might be due to several hours of
cleaning and having the doorlights on. Any advice, particularly of the
DIY variety would be greatly appreciated.

The starter circuit in the 740 is as simple and classic as they come - no
sensors or other mystery stuff. The battery should have lasted longer than a
few hours of the interior lights being on, so I think it's very likely to be
bad. One of the failure modes I've seen a lot in the last few decades is
what I believe to be broken connections inside the battery. When that
happens the car won't start and the headlights go out when you try the
starter. A shadetree diagnosis (and temporary repair) is done with a hammer,
around a 12 or 16 ounce is good. A few modest whacks, like driving a nail,
on each post often jams things back together and will get the car started.

Alternatively, just swap in a battery from another car if you can borrrow
one. After all, what are friends for?

Mike

 

[Michael Pardee]

Ohdeargodpleasehelpme, I recently charged a relatively new battery,
reinstalled it correctly, and now can't get the engine or starter to
turn over. Power windows, locks, lights all work, but no discernable
sound comes from the car, save for a slight clicking. My thinking is
that I have unwittingly "reset" some of the sensors, or some such
thing. I just bought the car ($700, so there was bound to be problems)
and am unsure of the condition of the alternator. The battery drained
quickly after I bought it, but it might be due to several hours of
cleaning and having the doorlights on. Any advice, particularly of the
DIY variety would be greatly appreciated.

Something I should mention, as you don't know how good the alternator is.
Believe the voltmeter more than the warning light. As long as you are
noticably above the red you are good. The most common alternator failure by
far in these is worn brushes, and I dunno for sure about the 1990 but in our
1985 the warning light does not come on when the brushes wear out. The
current to light the warning has to go through the brushes.... That
condition is also heralded by a real non-event; the "battery" warning light
does not come on in the "run" position of the ignition switch before you
start the engine.

When the brushes wear out (expect approx 150K mile life) they can be
replaced by replacing the regulator assembly they are built into and without
removing the alternator. The brushes themselves may also be available in the
Specialty Hardware section of Ace hardware stores (bring 'em in and match
'em up), but I'm not sure of that. Check back when the time comes.

Mike