Hyundai Repair: Ignition coil, coolant temperature sensor, hyundai scoupe

Question
I have a 94 Hyundai scoupe non-turbo that will not start when the weather is pretty cold.  I will turn and turn but will not start.  I have changed the plugs and wires as well as the cap and rotor but still same results.  Could my ignition coil cause the vehicle not to start when it gets cold?  Thanks for your help in advance

Answer
It's possible that the ignition coil is your problem, but there are many other possibilities as well.  You'll want to narrow the scope of things that could be the problem.  All checks below need to be done when the problem is occurring to yield meaningful results.

1.  Does your engine crank when it doesn't start?  Does it crank normally or slowly?  If it cranks slowly, suspect the battery.

2.  Does the check engine lamp come on for at least a few seconds when the ignition key is turned to the "on" position?  If not, you'll need to investigate why the engine control module (ECM) isn't powering up properly.

3.  Do you have spark?  If not, you should suspect the things the computer needs to see (such as the crank sensor signal) to fire the plugs and the ignition coil.

4.  Do you have proper fuel pressure to enable starting the vehicle?  If low, suspect the fuel pump.  If no fuel pressure at all, add to that a possible problem with the fuel pump control circuit.


One of my primary suspicions would be the coolant temperature sensor.  Mixture is very critical when starting a very cold engine.  A coolant temperature reading that's too cold or hot could cause the engine to flood or not have enough fuel to start.