Kia Hatchback Range

That’s a crazy set of circumstances, but it wouldn’t be the first time an apparently unrelated component has thrown another into disarray. On the surface, there’s no way the climate control or headlights could affect the way a transmission works, but here we are…

The most likely explanation is that the electrical gear that’s locking the transmission into third gear is somehow affecting the transmission’s speed sensor that tells the computer the vehicle is travelling fast enough to select fourth (top) gear. The body computer could be the culprit, but there could also be a problem with the car’s wiring loom that is creating this havoc. A poor earth could also be causing the problem and is a more common cause of transmission problems than many people imagine.

Frankly, about a thousand different things. Poor idling and performance can be down to the ignition system, fuel system or mechanical wear or problems anywhere within the engine. And within those three things can lurk potentially thousands more reasons for poor running.

A mechanic familiar with this make and model is your best bet. They will probably start with the basics such as fuel supply and quality, spark strength and timing and a compression test to make sure all is well within the engine itself. This is a case where it’s important to go back to first principles of fuel, spark, compression and then start to look at the more intricate systems that control the engine.

Honestly, though, it could be anything from a dud sensor in the intake system, the same problem with the cooling system (not allowing the engine to reach full operating temperature) or even something mechanically fundamental like a blocked catalytic converter, dirty filter or slipped camshaft timing. Or a multitude of things in between. A good workshop will be able to sort it, however, without simply swapping parts that may or may not be the problem.

It’s important to differentiate smoke from water vapour when it comes to problems like this that may not be a problem at all. Given you’re also seeing water being emitted from the tailpipe, I’m tipping that this is all happening when you first start the car in the morning.

The fact is, this is perfectly normal behaviour from a conventional engine and is simply the engine doing what it does. The water and water vapour is visible on these colder mornings we’re experiencing right now in Victoria because the exhaust isn’t yet hot enough to turn it to steam (steam is actually invisible, water vapour is the white mist you can see). As the car warms up and the exhaust gets hotter, it will turn the water into steam and you won’t notice it.

But how does the water and vapour get into the exhaust in the first place? Believe it or not, water is a natural by-product of burning petrol in an engine. And until the engine and exhaust are hot enough to turn that water to steam, it’s visible to the naked eye. Which is when a lot of people start to get worried. But they needn’t, as it’s nothing to be concerned about.

The flip-side is if the tailpipe is actually emitting white or blue-ish smoke, at which point you potentially have a worn or damaged engine. This will happen regardless of whether the engine is hot or cold and it won’t go away once the engine is warmed up. If that’s the case, you need to have the engine compression tested by a mechanic as the first step towards finding the cause.