Mitsubishi Problems

Running on after the ignition is switched off is more of a problem in petrol engines than diesels. But you haven’t told me which engine your Triton has, so maybe it’s the 2.4-litre petrol we’re dealing with here. If so, you may find that the running-on is being caused by poorly timed ignition which could suggest a problem with the physical bits that make up the ignition system, or even a problem with the computer that controls it all. Worn or leaking fuel injectors could also cause this problem.

If your engine is the turbo-diesel, then another potential cause of running on is a worn or stretched timing chain (the petrol engine uses a toothed timing belt which shouldn’t stretch) that has allowed the camshaft to get slightly out of phase with the crankshaft. In both these cases, the fault could easily be enough to trigger the check-engine light and keep it on to alert you to the problem. Have the vehicle scanned to see if there’s an ignition fault or what’s called a camshaft deviation, indicating a worn timing chain.

This is an older car now, and although it’s a simpler device compared to most newer cars, there are still thousands of things that can go wrong and cause a loss of performance. A full service and tune would be the first thing to do, as you may find the car is simply not running as well as it should be due to blocked filters, old spark plugs and possibly even stale fuel. A service and tune will rule out that sort of thing.

From there, you need to work out whether it’s the engine that’s the problem, or the transmission, or a poorly adjusted park-brake, or even something in the chassis like a binding brake or perhaps under-inflated tyres. All these things can make a car feel sluggish.

If you (or your mechanic) do decide that it’s the engine at fault, don’t rule out things like a blocked exhaust system, a dud sensor that controls the fuel injection or something simple like a vacuum leak as a result of a missing or burst rubber hose.

The answer depends on which particular engine your car is fitted with. In 2005, Mitsubishi gave the Lancer a facelift, at which point the ES version could be had with the original 2.0-litre engine or the newer and more powerful 2.4-litre unit.

If your car has the 2.0-litre engine, then it is fitted with a timing chain which should last the life of the car. If it’s the 2.4-litre unit, then it has a rubber timing belt which needs to be changed at regular intervals.

The general consensus seems to be that the belt-change interval for this engine is every 90,000km or six years, whichever comes first. Mechanics also recommend you replace the water pump and the various pulleys and tensioners at the same time to avoid having to disassemble the engine a second time when the pump starts to leak six months from now.

A dirty or clogged fuel filter will stop a modern turbo-diesel engine dead in its tracks. In fact, it’s one of the first things a switched-on mechanic will check on vehicles like yours. So if the mechanic has changed the filter and restored to car to full health, then I reckon he or she has probably nailed the cause and fixed it very simply and cheaply for you.

Let’s be honest; there are literally thousands of things that could go wrong that might make your vehicle stop. Modern cars are very complex things, but you need to have faith that sometimes, simple problems occur and can be fixed simply.

Transmission fluid should be quite red in colour and very translucent. Any time it’s not, you almost certainly have something going on inside the transmission. When transmission fluid turns brown or black, that usually indicates wear inside the transmission from either being overheated or from what’s called slippage.

The bands and clutches that create the flow of power in the different gears of the transmission are covered in friction material that gradually wears out (like a conventional car’s clutch plates or brake pads). These bands and clutches get hot enough to either 'burn', or slip when they should grip. In the case of overheating, the transmission fluid gets 'cooked' as well, turning it a darker colour. And if there’s slippage inside the unit, the friction material on the bands and clutches can be shredded (like sanding a piece of wood) and the abraded material (sawdust) collects in the fluid, turning it black.

Overall, black transmission fluid suggests internal wear and that a change of fluid and a transmission service is required immediately. This should return the fluid to its correct colour, but you need to monitor it over time to ensure the same problem isn’t continuing.

Fluid will darken over time (as the bands and clutches wear normally) but if the fluid has suddenly gone from normal to black, then you very possibly have internal wear starting to make its presence felt.

I’d agree that 13.3 litres per 100km is a bit of the high side, but to put it into perspective, you need to forget about the factory claim of 8.0 litres per 100km. That figure is determined by a laboratory test, not real-world driving and rare indeed is the vehicle that can match its test figure with its real-world number.

I would expect a number closer to 11 litres per 100km for this vehicle, but there are a lot of variables at work here. For instance, does the vehicle have a roof rack? Have you fitted a bull-bar? Does the vehicle roll on standard sized wheels and tyres, or are they taller, aftermarket tyres which increase rolling diameter and throw the standard gearing out?

The latter – in particular – can affect fuel consumption in a huge way, as can how you drive the car. High speeds or urban driving will also rapidly increase fuel consumption. If you’re still concerned, have the vehicle tuned to see if that makes a difference.

This has been an ongoing problem for many owners of many different makes and models of cars fitted with Diesel Particulate Filters (DPFs). The process of dumping fuel into the engine is designed to get the exhaust system hot enough for the DPF regeneration (self-cleaning) to take place. But a car that travels 500km per week really shouldn’t need this as the exhaust system should be getting hot enough in the normal course of things.

Either way, if you constantly have excess fuel being dumped into the engine, some of it will find its way into the sump (as you’ve discovered). That’s when the check engine light signals the problem, but in the meantime, you’re also driving around with engine oil diluted by the extra fuel. And that’s when engine wear can occur because diluted oil isn’t able to protect the engine’s metal parts as well as it should.

It could be that the car’s sensors are giving the computer the wrong information on how hot it’s getting, and/or how dirty the DPF is. Perhaps the DPF itself is damaged to the point where it won’t regenerate fully. A diesel specialist would be a good place to start, as this problem is hardly unknown these days.

That’s pretty outrageous fuel consumption and equates to about 30 litres per 100km when 10 to 15 litres per 100km is a more realistic expectation from a vehicle like this. And that points to something seriously wrong with the way the on-bard computer is supplying the fuel to the engine.

You need to start by running some checks including the fuel delivery pressure, as well as the various sensors around the engine that determine the fuel mixture. It could be as simple as a dud engine temperature sensor which is telling the computer the engine is stone cold, even though it’s not. But equally, you could have a problem with an oxygen sensor, a throttle position sensor or even a simple vacuum leak. Even a throttle body that is not adjusted properly or a dirty mass-air-flow sensor can throw things out of kilter and cause over-fuelling.

The danger is that, if you continue to drive the vehicle as it is, you’ll not only go broke putting petrol in it, but you might also damage the engine through the excess fuel causing damage to the cylinder bores.

The simplest answer is that the engine’s idle speed is set too low. I think these engines used a stepper motor to control the throttle at idle, and if this fails the engine will run with some throttle applied, but will stall at idle.

If that’s not the cause, you need to look a bit deeper into things like fuel pressure at idle and whether there’s some kind of problem with the fuel-injection system. It could even be something as simple as a dirty fuel or air filter. A good mechanic will know how to alter the idle speed to prevent this happening, although it may involve a new stepper-motor unit.