Diesel injectors

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Fri 31 Oct 2003 08:54
Diesel injectors - Dan G
Having read most of the threads on diesel emissions, and the use of fuel additive injector cleaners (which I use regularly), I have the following question:

If diesel smoke problems are just the result of the injectors, will replacing the injectors eliminate the smoke thus making the engine as clean as it was when it was new ? Or, are there other factors which contribute to smokey old diesels ? (OK, very dirty engines will be burning the engine oil).

How often are injectors replaced ?
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Fri 31 Oct 2003 09:30
Diesel injectors - Sooty Tailpipes
Well, I know the fuel pump can cause smoking, if worn or faulty.
As a diesel has no throttle plate and is effectively at Wide Open Throttle all the time, even at idle, the fuel injection quantity and timing is altered to vary power/acceleration.
When you press the accelerator, the fuel pump has to alter the quantity and timing of the fuel injected quite preceisely, because if it suddenly just sprayed it in at full tilt because you pressed teh accelerator all the way down, it would just die in a cloud of smoke. Basically the pump needs to know accelerator position, load, and engine speed, and change the fueling for optimum accleration, and continually alter these parameters as the engine speed changes.

A jet turbine engine fueling is similar in principal.
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Fri 31 Oct 2003 14:28
Diesel injectors - Andrew-T
Sooty seems to have answered a different question. AFAIK, injectors are rarely replaced as such, though they are sometimes taken out and cleaned (about £10 each?), though that is one purpose of diesel conditioner, which is cheaper.
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