Isuzu Problems

My experiences with the very latest turbo-diesel engines available suggests that DPF burn offs are being programmed to happen much more often. It’s likely to be a manufacturer response to the problems associated with DPFs that become clogged and then require manual cleaning or even costly replacement. By programming the DPF to burn off more often, the theory is that this will lead to fewer DPF blockages and other problems, making life easier for the car’s owner and reducing customer complaints.

Perhaps another aspect of this is that the DPF burn usually takes several minutes and kilometres of driving to complete. If the vehicle is stopped before the burn is complete, it may try again for a complete regeneration (burn) as soon as possible, which could be why you’re seeing these frequent notifications on the dashboard.

There’s a bit to unpack here. The first is that the D-Max is rated to safely tow 3.5 tonnes, so it’s not as if you constantly have the vehicle overloaded in terms of what it’s towing.

But if you also have the tray full of gear as well as 2.3 tonnes of caravan on the hitch, you might find that you’ve been inadvertently running overloaded for most of the time. It happens more than you think. At which point, the Pedders specialist is right; you need a suspension upgrade.

Even then, however, you still need to stay within the manufacturer’s maximum GCM (Gross Combination Mass) and the GVM (Gross Vehicle Mass) to stay legal. You can sometimes officially upgrade the GVM with a suspension upgrade that’s been properly engineered, tested and approved (which Pedders is a specialist in) but the GCM is generally not able to be upgraded according to the law in each state and territory.

But none of this explains why a vehicle designed to two 3.5 tonnes is wearing out its rear springs with 2.3 tonnes hitched up. Is the tow-ball down-weight within the legal limit (usually 10 per cent of the weight of the towed load)? Incorrect loading in this manner could affect the springs. Perhaps a fully-loaded visit to an accredited weighbridge might net more answers.

However, if it’s a simple case of the springs wearing out prematurely, then it’s possibly Isuzu’s problem to fix under warranty. Perhaps there was a bad batch of springs fitted at the factory that is affecting your vehicle and others built at the same time. Stranger things have happened.

Any time a diesel engine produces black smoke, it’s doing so because too much fuel is entering the engine. The danger then is that the engine will start to run hot and that can cause all sorts of meltdowns. But combined with a knocking noise, black smoke can also signal serious internal engine damage.

The best advice is to not drive it any farther and get a diesel specialist to look at it. Diesel engines often make a knocking noise as a normal part of their operation, but if this noise has changed, then something’s wrong.

This is an increasingly common complaint among car owners who are finding that modern driver safety aids such as autonomous emergency braking and lane-keeping assistance programs are too sensitive and don’t take into account the whole picture at the time. Examples include shrubs in a driveway causing the emergency braking to activate, and lane-keeping assistance trying to maintain a car in the centre of its lane despite a looming wide-load on a truck next to it.

I’m not sure what the solution is. But we can only hope that as cars get better and these programs more sophisticated, the errors won’t be as common. But while ever this tech relies on a computer and an algorithm, it will be doomed to (sometimes) fail. This is one of the reasons completely self-driving cars are not yet a reality on our roads; the tech is simply not foolproof yet.

Meantime, covering your car’s cameras with tape might put a stop to the false alarms, but it might also create new problems as the computer searches in vain for the camera’s input. And your concerns about insurance hassles are well founded, too. It’s not hard to imagine the owner of a car with disabled safety features being refused cover in the event of a crash.

Cars are often less than perfect and problems can show up once they are released on to a particular market with particular conditions. But every new make and model that hits the road and is eligible for registration has to pass a range of tests and certifications before the government will allow that to happen. So your question is really one for government, but the reality is that in many cases, nobody can see these problems coming.

Meanwhile, while I won’t speak for every `information’ source on the internet, I can say without fear of contradiction that no road tester or writer for Carsguide accepts payments from car importers for their opinion. Social media influencers may be a different matter, but I promise you that anything published on Carsguide is the truth and in no way influenced by the car maker or importer. We now live in an age where you need to be very careful where you source your information, but Cargsuide is one source you can trust. It’s something the writers (my colleagues) are very proud of.

Let’s start at the start. The SVS light on your car stands for 'Service Vehicle Soon'. Fundamentally, it’s telling you that something is not right somewhere on the vehicle and the computer has logged the fault. That’s why a scan showed up the code PO661.

On this vehicle, code PO661 relates to the electronics that control the swirl valve inside the intake manifold. This valve works to create the maximum gas velocity inside the intake runners and, therefore, gain the cleanest, most complete burn of the fuel and air entering the engine. If this valve is not operating properly, you may find a loss of power as the turbocharger won’t be working at its most efficient. In some cases, the same fault code can show up because of a problem with the engine’s EGR valve which is also part of the engine’s intake system. This may require the manifold to be removed and manually cleaned.

However, it’s unlikely to be anything to do with the car’s air-conditioning system, which is more likely to be a coincidence. That said, if the engine is running hotter than normal because the intake system is not working properly, then the car may have an interlock that prevents the air-con coming on to help keep coolant temperatures at bay.

It sounds very much like the vehicle has gone into limp-home mode. This is a self-preservation system whereby the engine and drastically reduces the power it’s producing, limits top speed and often locks the transmission into a low gear. Something has happened that has caused this, and a common reason is that something in the engine, fuel system, or (more likely) the transmission has started to get too hot with the strain of towing.

With luck, full operation will be restored once the vehicle has been allowed to cool down. But you may need to visit a dealership to have things reset. It’s always a good idea to do a full engine and transmission fluid and filter change after any overheating event anyway.

Okay, here’s the bottom line: All engines use a little bit of oil. If they don’t there’s either something wrong with the oil pump, or the owner is kidding themselves and not checking the oil level correctly. Modern turbo-diesels also 'breathe' a little oil back through the engine as part of the emissions control system, and owners with an aftermarket catch-can system often find a bit of oil winds up in there instead of being burnt in the engine.

The question is how much is too much. I don’t think 700ml per 2000km is excessive and your dealer’s views will be based on the official figure from Isuzu. But in the real world, owners are reporting oil consumption of around a litre to 1.5 litres per 5000km. At which point, your engine is right on the money.

How you drive the vehicle and whether you tow a heavy load will also affect oil consumption, as will ambient temperature and the type of oil you use. It’s a fact that modern, lower-friction engines are designed to use a little oil in the name of saving fuel, and it’s something car owners need to get their head around. Keep an eye on that dipstick and you should be fine. Checking the oil on a regular basis will also tell you whether the engine’s drinking habits have changed; a much more valuable piece of knowledge to have.

The list of possible causes for a modern turbo-diesel engine not to start would fill a pretty large book, and there’s no point trying to guess the problem. If the engine is cranking but nothing else is happening, most mechanics will start by looking at the fuel system. There could be a problem with the tank pick-up, the fuel rail, the injectors, the filters and many more components. But a check of the fuel delivery pressure and volume is a good place to start.

But this is not a job for the amateur in their driveway. Modern diesels use super high injector pressures, and, if there’s any residual pressure in the system when you crack it open, that pressure is enough to remove fingers, just like a high-pressure water jet can cut steel.

This is probably a simple case of an automatic transmission doing what it’s designed to do. In order to keep the engine in its comfort zone (and making sufficient power and torque to haul the caravan at the speed you’ve chosen) the transmission will shift through its gears to achieve that happy balance.

Any time you encounter a hill or even a headwind (and it’s more so with a heavier caravan) the transmission will assess what speed you want to hold, and then (via changing gears) keep the engine at a speed that supplies the necessary performance. Even a hot day can cause a change in the shift patterns as the transmission aims to take the strain off the cooling system by giving the engine and easier time. Again, a big, heavy caravan will amplify this effect.

However, if the transmission is changing gears for no apparent reason, then you may need to have the calibration checked and perhaps even reprogrammed. Don’t forget, though, that a modern transmission is a pretty clever piece of gear that can even choose to shift down gears going downhill to take the strain of the vehicle’s brakes. Don’t confuse an active transmission with a dud one. And if you still think the behaviour is odd, then an electronic scan of the vehicle might provide more information.