Ask The Guide

I’m amazed that you managed to find such a convoluted reset procedure, even if it only provides a temporary fix. You may well be right that this behaviour is linked to heat build-up, especially if it happens after several hours of driving.

It’s interesting that you mentioned the engine sometimes goes into limp home mode, because the transmission’s behaviour sounds a lot like it’s going into limp home mode, too. Limiting the gears the vehicle will select is a classic symptom of limp-home mode, in fact.

The real question then becomes, what’s causing it to do so. Limp home mode can be initiated any time the vehicle thinks that continuing to drive at full power or speed will do further mechanical harm. As such, there’s a huge range of things that will cause limp home mode to engage, including a leak somewhere in the turbocharger’s plumbing, low coolant level, low oil pressure, low fuel pressure, a faulty sensor and many more.

So the first job is to scan the vehicle and see what fault codes are thrown up by the computer. From there, you can home in on the actual problem and fix it. But without those codes, you’re kind of flying blind.

On this model, the sensor in question is located on the crankcase (not the cylinder head as many are). You’ll find it on the driver’s side of the crankcase, below the intake manifold. Replacing it involves removing the old one by screwing it out, and screwing the new one in. But there’s a bit of a process for this, and if you’re not familiar with this type of job, it’s probably one for the experts.

The sensor is located between cylinders three and four and it’s located pretty close to the manifold. The good news is that you don’t need to remove the manifold to access the sensor; you can get to it by going into the engine bay through the wheel-well.

Don’t forget that you’ll lose some coolant in the process, so that will need to be topped up with the correct type afterwards. Remember, too, that the new sensor won’t work unless you correctly reattach the wiring plug that connects the sensor to the rest of the car. This area can be pretty grimy and muddy in a vehicle like this, so cleaning everything off first is a good idea.

This model Hyundai i40 had two different automatic transmissions depending on which engine was fitted. If you have the petrol engine, the transmission will be a conventional torque converter six-speed automatic. However, if your car has the turbo-diesel engine, the transmission will be a seven-speed dual-clutch unit. At which point things change.

These dual-clutch units (and not just Hyundai’s) have shown themselves to be a bit under-engineered in some respects. And when they start to develop wear in the clutch packs, they can definitely start to behave poorly including rough shifting, shuddering when moving off and other problems.

But either way, you are going to need the services of a transmission specialist to determine what’s wrong. Even if you have the conventional automatic version, you might still find it has serious internal wear or failures, but only a detailed diagnosis will tell you the whole story.

On the other hand, you might be lucky and simply have a transmission with low fluid level that will be restored to health by a top up of that fluid. You’ll still need to find from where it’s escaping, however, as this is a sealed system and should not lose fluid over time.

The 160Z was not a car we saw in Australia and, I believe, was more or less a South African-only model. Australia’s closest relative would have been the 120Y Coupe. As such, I’m not too sure about the way the fuel lines were routed from the fuel pump to the carburettors, but in the case of the larger 240Z Coupe which also used twin carbs, the fuel system in the engine bay consisted of a common fuel rail with rubber hoses leading to each carburettor.

So, for the pressure to be uneven in the two carburettors, you’d probably need to have a restriction or blockage in that rubber line or a problem with the needle and seat of the carburettor in question. The thing is, I’m not sure how you’d know you had a pressure differential unless you’d fitted an external pressure gauge to each carburettor’s supply line, as Datsun certainly didn’t provide such a gauge.

Perhaps you mean you have unequal vacuum at each carburettor and this is a much more common scenario. You can check for this with a vacuum gauge, noting whether one carb is `pulling’ more vacuum than the other with the engine running. From there, you can use the adjustment screws on the carburettor to match, or 'balance' the two carbs so they contribute the same effort in making the engine run.

This sounds simple, but it’s actually a job for a specialist who understands old carburettor designs and how to make them work properly. It’s a bit of a dark art, but rally workshops and mechanics that specialise in classic cars are a good place to start looking.

By the way, my information suggests that the carbs on your car are made by Hitachi and, therefore, are more likely to be a Japanese copy of the SU carburettor that has been turning motorists into mechanics for decades.

You’ve probably already figured out that the two codes mean you potentially have two separate problems, but either one of them could cause your car to switch to limp home mode. In any case, they both need to be fixed.

So, let’s start with the PO118 code. This suggests you have a faulty engine coolant temperature sensor. When this fails, the computer isn’t getting the information it needs to know whether the engine is cold or warmed up. As a result, the fuel-air mixture will be all over the place and the vehicle will possibly use more fuel and run poorly as well as being hard to start in the morning.

The other fault code you’re seeing, PO489, is to do with the engine’s exhaust gas recirculation valve. This valve channels some of the engine’s exhaust back through the combustion chambers to reduce tailpipe emissions by burning the same gasses twice. Your car’s computer will be constantly opening and closing this valve, but it’s an electrical signal (from a sensor) that tells it when to do so. If this sensor has failed, that information won’t be getting sent to the computer and the check-engine light will come on.

Both of these faults will probably be fixed by replacing the sensors in question, but until they are replaced, the car will continue to throw fault codes and switch to limp home mode.

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.

A quick test will tell you whether the alternator is sending charge to the battery. If it isn’t, then you need to start checking the wiring and things like the whether the car is earthed properly. Perhaps there’s a blown fuse of circuit breaker that is preventing the flow of charge from the alternator to the battery.

If the alternator is, in fact, charging the battery when the engine is running, then you’re looking for a problem such as an aftermarket alarm or a boot light or some other electrical gremlin that is draining the battery overnight. It would also be worth checking that the new battery and alternator for correct operation and capacity. It wouldn’t be the first time a brand-new component has been faulty, fitted to a car and then confounded the mechanic responsible.

Your mechanic is spot on. As far as the warranty laws in this country are concerned, there’s no difference in having the vehicle serviced by a Ford dealer or by a qualified independent mechanic. If there’s a problem down the track, it won’t matter who serviced the vehicle; a warranty claim is a warranty claim. Your peace of mind should be no different either way.

The only difference might be if Ford looks more favourably upon your case considering you’ve been a loyal customer and had the servicing done by your dealer. But don’t go to the bank on that, as it’s by no means a legal requirement, nor a widespread occurrence.

The only recall I could find for a Chery Tiggo (specifically the Tiggo 4 in this case) was for almost 2000 examples where the audible alarm for the autonomous emergency braking system was not activated and may not have sounded to warn the driver. The cars in question were, indeed, made in 2024, so your vehicle may well be one of the affected ones.

There's a list of affected VINs (Vehicle identification numbers) listed on the recalls site for you to cross-check, or a check with your Chery dealer will reveal all.

It’s not uncommon for owners of new vehicles with dual-clutch transmissions and throttle-by-wire to technology to feel a bit at odds with the way the car behaves. The feeling of a stilted, hesitant operation mirrors your experience to some degree. Over time, this sensation can be reduced. But it sounds as though your experience is a bit more dramatic than the norm.

In the first instance, give the dealer the opportunity to check the car out and make it right if there’s a problem. Modern vehicles like this can be scanned and the operation of their major functions graphed to show whether they’re within tolerance or not. There may be a software 'patch' in the works at Haval to address this.

If that doesn’t satisfy you, you can contact Haval Australia’s customer service department and lodge a complaint. Finally, if none of that does any good, you can contact the ACCC as a car sold brand-new that is not fit for purpose falls within the commission’s sphere of influence. You may find an independent test report of the vehicle’s behaviour would be a handy thing to have if you go down this route.

A $200 aftermarket throttle controller may, indeed, produce a vehicle you are happier to drive, but you should definitely check with Haval first to see if there are any warranty concerns in fitting such a device. Some advertisers of these devices claim there is no warranty issue, given that Haval would need to prove the throttle controller was the cause of any mechanical issues in the future. We’d still check with Haval before committing, however.