[Engine] New forum user 1200 rpm diesel knock

[Downs grinder]

Looking abit of help

2016 1.6hdi

At 1200rpm I'm getting a diesel knock... But power regains once passed... Had it to local garage today and put it on a computer and reading live data on a run but they are tell me it's not coming back with any issues, also for the last 10 month I've had a intermittent issues going from 4th to 5th and once in 5th gear getting a slight shudder and power dropping with the shudder getting worse.... I noticed this morning and also told the mechanic that by the injectors there seems to be feul leaking, also there is no warning lights getting thrown up onto the dash.. Mechanic advised me that this is run off fuel not getting used or possibly from the last time the fuel filter was changed, the van is well serviced as and when needed without fail.

Advice given from the mechanic today was to keep running as it is and see what happens.

Something clearly isn't right here and I think I'm possibly being fobbed off by the garage... Any help or advice will be greatly appreciated.

[OMG]

You need to see if any fault codes are being generated. Using the Citroen diagnostic ‘Diagbox’ would be the best bet .

[shtu]

At 1200rpm I'm getting a diesel knock... But power regains once passed..

Classic symptom of failed injector(s).

Look for my posts on here and on French Car Forum for a heap of background info.

The key thinkg to look at in live data is the correction values at idle - there's a fair chance you'll see numbers like, eg,

1.0
1.0
0.75
1.0

The one with the large variance is likely a dud.

[geoff]

The first thing to do is to fill up with premium diesel and also put in an overly generous / heavy dose of diesel system cleaner into the fuel tank and then give the stuff a good few miles to work.
If you only drive gently and locally then give the vehicle some speed and some " work " to do.

After this if the issues remain at least you'll have a good base line to work from.

[shtu]

The first thing to do is to fill up with premium diesel and also put in an overly generous / heavy dose of diesel system cleaner into the fuel tank and then give the stuff a good few miles to work.

While always worth a shot, all it did for me was cost £10.

Two bottles in a tank, drove most of the M6 in 4th, no effect.