2009 Holden Colorado Pricing and Specs

Any excess smoke from a diesel engine can mean a too-rich mixture. So are you certain the injectors are the correct ones for that engine? Has a sensor been bumped during the replacement process that is not sending the right signal to the computer that controls the injection on a modern turbo-diesel?

Also, cold-start problems in an engine like this are often traced to the glow-plugs. These are crucial to warming up the cold engine internals so that combustion will take place. So perhaps a check of the glow-plug wiring is in order as this could have been disturbed while the injectors were being replaced.

Has anything else been changed or replaced as part of this process? Has the engine been sitting for an extended time (allowing the fuel to go stale)?

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).

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.