Holden Colorado Engine Problems

Any vehicle of this age can start to experience wear in the turbocharger. These units live a very hard life, spinning around at something like 250,000pm and operating in a very hot environment. Cracks can occur in the housings, the bearings can wear and even the blades of the turbocharger itself can break or become bent. All of these things will affect performance. And, unfortunately, it sometimes doesn’t matter how well the vehicle has been maintained. Turbos have a finite lifespan and that’s all there is to it.

But don’t simply assume that a lack of performance is due to turbocharger failure or wear. Sometimes on this model, the Exhaust Gas Recirculation (EGR) valve, which is designed to re-burn some of the engine’s exhaust to reduce tailpipe emissions, can become stuck open, reducing boost pressure and, therefore, performance.

Many workshops specialise in turbo-diesels these days, and should be able to help with a diagnosis.

The biggest issue owners have experienced with this car is a tendency for the engine to consume oil and require a top-up between oil changes. Holden addressed this by changing the specification of the oil from a 5W30 to a 5W40 oil and released a new oil cap design. You’ll know if the new-design oil cap is fitted to your car as the owner’s manual will have been altered by a Holden dealer to reflect the new oil specification.

Beyond that, the biggest driveline complaint seems to be the noise generated by the engine. However, this seems to be a natural by-product of the 2.8-llitre turbo-diesel fitted to the Colorado 7 and is not a fault per se.

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.

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.

Even if the two cars were from the same production month and year, you’ve got some serious mis-matches there; enough to make the job far more time, effort and money than it’s worth. For a start, the two-wheel-drive Colorado won’t have the extra differential and drive-shafts to mate with the twin drive-shafts that the all-wheel-drive gearbox will have. So you’d have to somehow blank that front driveshaft off. Or, add the front differential and axle which will also probably require different front suspension. Prop-shaft lengths are likely to be different between a manual and an automatic version of the same car, too.

Then there’s all the other things that can suddenly catch you out. In many cases, the manual and automatic versions of a particular car will have different transmission tunnels and different holes in the floor for the shifter to poke through. Even the centre consoles can be non-interchangeable. The dashboard of an automatic car with its PRNDL display will also be different to the manual one. Then there’s the question of wiring looms which can also be vastly different to suit the specific requirements of each driveline layout (a modern automatic needs lots of electrical inputs). In fact, the on-board computer is very likely to be different between the two transmissions on that basis as well.

Following on from that, what about the sensors to control the all-wheel-drive system? Or even the rotary dial inside the car to select the different four-wheel-drive modes? A two-wheel-drive car just won’t have them nor even possibly the access points to add them. And what about the real basics? Things like the automatic car not having a clutch pedal. That requires a full pedal change inside the car. None of this stuff is simple, easy or cheap.

To be honest, the engines themselves are very possibly interchangeable, but even if that’s all you swapped (and not the transmission) you’d still need to change the flywheel and plenty of little details.

By far the best advice is to simply buy the version of the Colorado you want.

Most glow-plug systems in diesel cars work on a timer system. The manufacturer will have worked out that X seconds of current will heat the plugs to a temperature sufficient for easy starting, so that X-seconds period is where the timer will be set.

What happens, though, is that glow plugs can lose their efficiency over time (and with 233,000km on board, your car is a candidate for that to have happened). As that efficiency is lost, they don't produce the same amount of heat as they used to and, therefore, the timer isn't giving them long enough to heat the combustion chamber sufficiently. When that happens, the engine becomes hard to start. The other possibility is that the timer itself is faulty and isn't giving the plugs power for long enough. The fact that your engine starts easily after the first cold start of the day, suggests the glow-plugs are, indeed, at fault here.

The other possibility is that the car's electrical system is not sending enough voltage to the glow plugs to make them work properly. This can be verified quickly and easily with a voltmeter. This method can also verify the length of time the timer is supplying power to the plugs.

In vehicles where the timer has already shut off the power to the glow-plugs before enough heat has been generated, the solution is often a new set of glow-plugs. The good news is that these aren't expensive, nor are they difficult to change if you know what you're doing. The caveat is if you aren't sure of what you're doing, at which point the fuel system on a common-rial diesel injection system can be very dangerous to tamper with due to the super-high pressures involved.