Rep Power: 0

Like the title states, I have a 2005 Civic EX that isn't starting if it sits outside overnight. It's been extremely cold here lately, and half of our garage is taken up with woodworking machines so the Civic pretty much lives outside full time.

Here's a little bit of recent history on the car, as we have had a few check engine codes in the past two weeks. The first code was for the camshaft position sensor, so we replaced that and it ran great for a few days and then the check engine light came on again. This time, the code was p0420 for the catalytic converter. Our mechanic hooked up his sensor to the car and looked through some of the diagnostic info and came to the conclusion that we should probably replace the upstream and downstream O2/air-fuel sensors.

After buying the sensors, I went to drive it to my mechanic to have them installed but the car wouldn't start. It had been very cold and I tried putting a new battery in it because our battery is old but that didn't help so we had it towed. While trying to figure out the not starting issue, our mechanic noticed that the spark plugs were wet with fuel, so we went ahead and replaced those as they were very old anyway.

After replacing both of those O2 sensors and resetting the check engine light, It drove fine all the way home. But after sitting outside overnight it wouldn't start. We pushed it into our garage and after warming up a little bit it turned on.
So now we have a car with no check engine lights on, but the inability to start after sitting in the cold. I am not super mechanically inclined, so I thought I would ask you guys. Anyone have any ideas?

 
Rep Power: 211

Did the mechanic opine on what is causing fuel on the plugs?
Were all four plugs wet?

 
Rep Power: 0

I don't remember him saying anything, but I can ask him. I'll also ask if it was all 4 plugs.

 
Rep Power: 211

Are the new o2 sensors NGK, NTK or Denso brand?

 
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Yes they are. The camshaft sensor was not though. It was just one I picked up from the local Advanced Auto.

 
Rep Power: 223

Needs to be an oem cam sensor, does the car have a block heater?

 
Rep Power: 0

Okay, I heard back from my mechanic and he did say that all four of the plugs were wet and have been replaced. All he said about what was causing it was that it was flooded.

 
Rep Power: 0

The car does not have a block heater. At least not one that I'm aware of. Would the non-OEM camshaft sensor malfunction in incredibly cold weather?

 
Rep Power: 223

It could, they're a complete crapshoot. Plugs being wet from repeated failed start attempts is normal. However if the plugs are soaked then they need to be dried before trying to start again.

 
Rep Power: 0

I did try to start it several times so that probably explains the soaking wet spark plugs. I'm sure it's possible that there is some other underlying issue, but I imagine me trying to start it so many times was probably the culprit