Advice needed - rattling noise on starting when engine is very cold

[KZTE Nut]

Hello Manne

My KZTE (330 000 km) makes a horrible rattling noise on starting when engine is very cold and then noise goes away after a few seconds. When the engine is warm there is no rattling noise when starting.

The injector tips were replaced about 100 000 km ago so I think that is not likely the problem.

On the internet they talk about the "death rattle" which is caused by sticking injectors and low sulphur fuel which has less lubrication. I am using 10 ppm diesel.

Or could it be the glow plugs that are the cause of the problem - they have never been replaced.

Hoping for some wise words of wisdom...

[Knuppel]

The rattle you hear is a diesel knock from having incorrect injector timing.

What the cause is is difficult for me to say. Have had three vehicle with the same symptoms in the past. Most likely a problem with the injector pump.
There could also be a wiring problem as the wires that go onto the injector pump are become very fragile with age if they have not been correctly secured.
Also they tend to develop and earth wire problem usually in one of the earth wires on the passenger side of the engine bay near the fire wall.
Lastly it could be the ECU, had to replace an ecu on one of them.

Hope you find the problem. Get it sorted as it just gets worse.

[KZTE Nut]

Thanks Marius
The problem only happens in winter and when engine is cold. There is no problem when engine is warm and I start it. Your mention of the injector pump makes me think that it could be the injectors that are going bad....
I am going to fill up with 50ppm on my next tank to see if the additional sulphur "lubricant" eases the problem and then the injectors are the main suspect...

[Knuppel]

Dont believe it will be injectors, could also be the could start setting from the ECU overreacting a bit and then retarding timing too much causing the diesel knock/clatter/rattle.
Could also be the ambient temperature sensor that has gone haywire, situated in the intake pipe. Disconnect it and see if there is any change in the sound. You can also pull it out of the rubber mounting and warm it with your hands before starting to see if there is a change!

[KZTE Nut]

Thanks Marius, I will give that a try.

[EchoMan]

Hi Mervyn. I don't have a clue what is causing the rattling noise, but wonder why you are using 10 ppm or even 50 ppm diesel ? I have tried 10 ppm a while ago for 2 tanks, and the truck was not happy at all. With 50 she is slightly better but still sluggish ! For me 500 ppm works the best and the improvement in performance is noticeable....and you save a few bucks in the process! For the past few years I've been adding 250 ml two stroke oil after every 5 tanks or so, and the motor still runs like a swiss watch. Nothing replaced as yet...done 220,000 kms