Hyundai Repair: Hard to start in cold weather, coolant temperature sensor, fuel pressure regulator

Question
What could be the problem when the car turns over fine but does not want to start when the temperature drops to around 30 degrees or below. The car will eventually start after several tries and long cranking times. I do all recommended maintenance, tried adding water remover and gas treatment. 1999 Hyundai elantra, 2.0L engine  Thanks

Answer
I'd first recommend checking the battery.  Battery voltage sometimes gets low enough that the engine will crank slowly but there isn't enough voltage to operate the computer or enough engine speed for the engine to actually start.

Another common problem on long cranking is a faulty fuel pressure regulator.  If it allows the fuel pressure to bleed off while the car is not being driven, the car will need to be cranked considerably to build the fuel pressure back up.

Since the problem is temperature dependent, you might also check to be sure the coolant temperature sensor is working properly.  If not, you may not have a fuel mixture that will enable the vehicle to start.

As long as the battery checks out, the most instructive thing you can do is to try to narrow the problem when it's occurring.  You'll want to know whether the check engine lamp illuminates during the bulb check.  You'll want to know whether you have spark from the spark plugs.  The idea is to figure out what's missing from the necessary ingredients to run the engine and then start searching the things that could cause that problem.