4.2 td pre ignition

[ben 4.2td]

I was wondering if it is normal for the 4.2 intercooled TD to suffer from pre ignition, as my 4.2 does it on a regular basis either hot or cold. Took it to a diesel mechanic but he could not work out why it pre ignites when shutting engine down. I was wondering will this damage the motor.

[BigRAWesty]

Its possbly the shut off valve not closing quick enough, and the engine running lean for a rotation.

cheers, kallen

[ben 4.2td]

I thought it could be the injectors as they are still the original and done about 140 000, think the recommend changing around 140 000

[nissannewby]

How do you drive it? Do you let it idle down before shut off? Also as above check the shutoff solenoid.

Sometimes if they have been driven very nicely you can get carbon build up and if you shut off straight away it can run on a touch. Did the mechanic check your injector pump timing at all? Its unlikely to be a pump issue. I don't know about injectors, the ones in my ute have gone close to 300k and are original. If you have injectors issues there are usually other symptoms of this like hard starting, loss of power, fuel consumption.

[ben 4.2td]

I drive fairly easily, sometime drag off other 4wd and 2 litre juice carton turbo sedans at lights, turbo is oversized and 3 inch exhaust mandril bent, taken it two mechanics, one said injectors at a crazy price and other mechanic could not find anything wrong, I am not to concerned as long as it doesn't damage the engine.