Won't start in cold weather

#1

I have a 1998 dodge durango and any time it gets under about 30 degrees,it takes about 10 to 20 times trying to start before it starts. One morning when i knew it was not going to start I popped the hood and I pulled a plug wire off a spark plug and plugged a spark plug into the wire and when my wife tryed to start the car it had no spark until she tryed starting 10 or 15 times and then all of a sudden it had spark. So what could be causing it to not have spark in cold weather??? One mechanic told me that it might be the crank sensor,but usually when the crank sensor goes bad the tach doesn’t work,and mine does.



#2

How old is the battery? Any codes?

It takes a lot of juice to turn over a cold engine. A weak battery may not have enough additional juice to also provide a strong enough spark to jump the plug gaps. While I agree that this cause usually means it just slows down cranking until it dies completely, it needed asking.

Have you checked your battery cable connections? There is theory that current running through a cold corroded connection could warm it up a bit and might provide less resistance in the connection. Resistance means voltage drop, and less resistance means more voltage left over to start the engine. Others here will now begin to jump on that and we’ll debate the theory, as we always do (we enjoy doing this), but the bottom line is that you should clean and reconnect your battery cable connections, or at least check them.

By the way, I’ve heard of an internally broken battery post doing weird things like this too.