[geeks] car question

[geeks at sunhelp.org]

Got it! Sounds like you may have had the jumper cables backwards.

With NO battery to speak of, there was nothing to oppose the polarity
reversal. The engine didn't start because it was turning backwards.

Unfortunately, if this is what happened, it can do damage. The voltage
regulator, radio, electronic ignition and engine management system
(computer) might give you trouble. If the car doesn't run with a new
battery, I would start checking the computer (not easy) and ignition system
(easy). On the other hand, these devices (hopefully) have polarity reversal
protection, which isn't hard or expensive to include in manufacturing and
design.

I have reversed jumper cables before (twice). In my case one car (a
Cadillac) got very upset about it, and the other (a Ford truck) didn't care.
Each time the battery had some life left and let me know how careless I had
been (big sparks).

James Fogg, Network Engineer
Vicinity Corporation - New Hampshire
(603) 442-1751

~ -----Original Message-----
~ From: Amy [mailto:scoobydoo at ohno.mrbill.net]
~ Sent: Monday, March 11, 2002 3:46 PM
~ To: 'geeks at sunhelp.org'
~ Subject: RE: [geeks] car question
~ 
~ 
~ On Mon, 11 Mar 2002, Fogg, James wrote:
~ 
~ > Much too weird.
~ >
~ > I wouldn't run it until you check something. Start the 
~ engine and take a
~ > voltmeter and see if the polarity of the system is correct 
~ (red wire to a
~ > live fuse in the block, black wire to chassis, if the meter 
~ swings backwards
~ > you're in trouble.
~ 
~ hrm. i guess i'll need to buy a new battery to start the 
~ engine (the old
~ one wouldnt hold enough stuff to turn over)
~ 
~ > Unless the battery was stone cold dead and you reversed 
~ polarity on the
~ > battery when you jumped it?
~ 
~ what if the jumper cables were wired wrong, in reverse? is 
~ that possible?
~ 
~ > If that was the case the battery would have
~ > gotten warm when you ran the engine.
~ 
~ it never ran. it tried to turn over, but i guess it didnt have enough
~ power. it wasnt dinging (door sounds when its opened), even.
~ 
~ > It also means the starter would have
~ > turned the engine backwards. A modern engine shouldn't run 
~ backwards (but a
~ > diesel engine can run poorly in reverse, depending on design).
~ 
~ gak. now i'm really getting worried.
~ 
~ --a
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