Holden Colorado Problems

You really can’t afford to take any chances with a car’s steering system. The thought of this crucial system failing even at low speeds doesn’t bear thinking about, so if there’s any play or looseness in the system, it needs to be diagnosed and fixed properly with new parts if necessary.

Meantime, Loctite and other thread-locking products are designed to stop fasteners coming loose. These products are not designed to take up slack in worn parts and shouldn’t be used that way. Even if the thread-locker stops the fastening nut coming loose, it won’t do anything about the slack in the joint you’ve already noted.

I think you’re on the right track by concentrating on the information being conveyed by the crank-angle sensor. But the problem is more likely to be a stretched timing chain rather than a dud sensor. The V6 engine in your Colorado is notorious for this problem and, when it happens, it throws the camshafts out of synch with the crankshaft. When the crank-angle sensor and the camshaft-angle sensor can’t agree that the positions of the crankshaft and camshafts relative to each other are correct, the problems start.

This lack of synchronisation is one of the things the crank-angle sensor is paid to look for and why it’s limiting engine speed or not allowing the engine to start at all. By clearing the fault code and disconnecting the crank-angle sensor, you’re stopping the error information being sent to the ECU and the ute starts first time (it’s probably taking a camshaft-angle reference when it can’t find the crank-angle information).

The starter motor would be a very good place to start looking for the problem. If the battery checks out (and that presumes you’ve load tested it, not just run a voltmeter across its terminals) and the addition of a second jump battery only just turned the engine over, then, the starter motor is a likely suspect.

But don’t forget things like a poor earth somewhere on the car or a dodgy ignition or starter button. Once the engine is running, check the power going into the battery. You should be looking at between 13.2 and 14.5 volts going into the battery with the engine running if the alternator is pulling its weight.

Just because the battery indicator is showing green, does not mean categorically that it’s in good health. It can produce a surface charge that might show 12 volts with no load on it, but can fall to its knees when you load it up with the starter motor.

There could be a complex, electronic, fuel-supply or engine-management reason for this, and if that's the case, having the vehicle scanned would be a good place to start. Or, it could be a case of human behaviour that is skewing your fuel economy figures.

By which, I mean that when you got the car brand-new, you gave it the kid-gloves treatment, understanding that the brand-new engine needed to be run in and would appreciate a slightly easier start to life. Then, as the novelty wore off and the vehicle began to earn its living, you subconsciously grew a heavier right foot. And it is this that's seen the fuel consumption creep up.

Failing that, you might have an on-board computer that has been silently recalibrating itself, perhaps in conjunction with software updates at the dealership which you may, or may not have, been made aware by the dealer. To be perfectly honest, I'd find 6.4-litre per 100km average on a Colorado borderline unbelievable, and the sort of economy only a dedicated fuel-saving driver could even get close to. Ten litres per 100km, meanw

Modern vehicles like the Colorado have lots of sensors to help prevent major engine melt-downs. One of those is the sensor that tells the car the engine oil level is too low for safe operation. If that sensor is sending bad information to the car's computer, the vehicle might be programmed to go into limp-home mode or even shut down altogether to preserve the engine.

But the oil problem the car is reporting could also be dangerously low oil pressure or oil that has become too hot. The farther and faster you travel, the hotter the oil becomes (up to a point) and the thinner it becomes, meaning it may not be thick enough to sustain safe oil pressure. This could also be caused by a dud sensor, but it could also be a real situation. And like the low oil level sensor, this can force the engine into shutting itself down as a self-preservation measure.

It sounds counter-intuitive that an engine would run at all with the crank angle sensor removed. Generally, without this sensor working properly, the fuel-injection system has no idea when to inject the fuel or fire the spark plugs. But sometimes – as in this engine – if the computer can't 'find' a crank angle input, it will take a reference from the camshaft angle sensor and use that to time the injection and ignition.

Even so, if the problem persists after two replacement sensors, it's probably fair to say this particular sensor is either not the root of your problem, or that or the engine's wiring is frying the new sensors as fast as you're changing them.

Either way, a trip to an auto electrician seems like the next logical step. Chances are a switched on sparkie will have seen this exact problem before and will know how to deal with it or at least take the logical steps to diagnose what's going wrong. Simply continuing to change bits and pieces is often an expensive way to solve a problem like this.

I'm curious to know what happened when the hill-start assistance kicked in on the flat. Since this system holds the car on a hill so you can move off easily, it should deactivate as soon as you press the throttle to move. Which means, on a flat surface, you shouldn't be able to feel the system at all. Are you sure this is what's happening. Could the problem instead be a brake caliper that is sticking on, or a hand-brake that is dragging?

In any case, the hill-start system is controlled by sensors that detect that you're parked on a slope and then apply the brakes to stop you rolling back. If any of these sensors is kaput or not sending the correct signal back to the computer, the set-up won't work properly. Conceivably it could engage on the flat but, again, I don't know how you would know.

But the solution is a simple one; take the vehicle to a Holden dealer who will be able to figure out what's wrong and then fix the problem under warranty. Your car is covered by a five-year warranty, so make the most of it.

By the way, disconnecting safety gear is not the best way to go as it can (obviously) make the car less inherently safe and, in some, cases even render the vehicle technically unroadworthy.

Here's a pointed question: Does your vehicle have an aftermarket trailer-brake system fitted? If it does, it's quite likely that the wiring passes through the cabin somewhere near where your leak is located. Unless this access hole is correctly sealed with the proper grommet, there's every chance water is getting in at this point.

Other likely suspects for this include roof mounted aerial holes, roof rack attachment points and even worn or damaged window and door rubbers.

A diesel that will turn over but not fire will often have a problem with its fuel system as the cause. You may need to check the fuel pressure and the pump itself, but other causes can be blocked or worn injectors and blocked or dirty fuel filters. A car with faulty glow-plugs can also be difficult to start from cold. But even things like a blocked air filter or something else fundamental to the car's operation could be the cause. And while it sounds simple, is there actually fuel in the tank?

If the solution doesn't present itself simply, the best advice is to have the car electronically scanned to check for fault codes the on-board computer will have logged.

A wobble or vibration big enough to be felt through the floor that suddenly occurs for no reason, can often be traced back to a wheel balance issue. If the wobble is worst through the car's steering wheel, it's likely to be a front-wheel balance issue, otherwise we'd be looking at the rear wheels.

The generally terrible state of our roads at the moment is probable cause for this, and a decent impact with a pothole can be enough to dislodge the small weights on a car's wheel that make it balanced and, therefore, rotate smoothly. When you consider how fast a wheel is turning at 100km/h, you can imagine that a small imbalance can be enough to produce a big wobble.

The good news is that this is a simple fix. A visit to a tyre specialist will soon determine of a wheel balance problem is the issue and it can be fixed quickly and cheaply with the replacement of the small, lead weights which are stuck to the car's rim. While the wheels are being checked, it's a good idea to examine the tyres, too. A tyre with structural damage or a flat spot an also lead to this type of problem.

If this doesn't turn out to be the cause of the wobble, you then need to move on to other components like the driveshaft and universal joints and even suspension bushes and shock absorbers.