CDTI Judders over 2000 RPM

Geoff130 · 26th March 2020, 16:45

My CDTI has been running fine since changing the fuel pump relay (Intermittent starting) Recently it's learned a new trick, somewhere around 2000 to 3000 RPM it feels like it's misfiring or juddering and won't rev any more. It's not always at the same point and sometimes it's not evident until really pushed. TOAF says the LP pressure is a little over 3 bar at idle and drops to 3 when revved, no ECU faults. It may be a coincidence but this started after I topped up the tank with about 10 litres of fuel. I did check the receipt and it was definitely diesel. The plenum is dry and it's the same with or without the MAF. I also tried disconnecting the control pipe to the EGR but still the same.
Any ideas where to start looking.

Nobby · 26th March 2020, 20:37

Sounds like an injector fuelling problem imho. Try a tank full of Forte Advanced diesel treatment to clean the system through as it might just be a simple issue of a dirty or sticking injector. Or you could try a leak back test which would identify a duff injector

26th March 2020, 16:45	#1
Geoff130 Loves to post MG ZT 190, Rover 75 CDTi, Honda VFR 750, Honda CB550F Join Date: Aug 2010 Location: Derby Posts: 393 Thanks: 75 Thanked 36 Times in 28 Posts	CDTI Judders over 2000 RPM My CDTI has been running fine since changing the fuel pump relay (Intermittent starting) Recently it's learned a new trick, somewhere around 2000 to 3000 RPM it feels like it's misfiring or juddering and won't rev any more. It's not always at the same point and sometimes it's not evident until really pushed. TOAF says the LP pressure is a little over 3 bar at idle and drops to 3 when revved, no ECU faults. It may be a coincidence but this started after I topped up the tank with about 10 litres of fuel. I did check the receipt and it was definitely diesel. The plenum is dry and it's the same with or without the MAF. I also tried disconnecting the control pipe to the EGR but still the same. Any ideas where to start looking.

26th March 2020, 20:37	#2
Nobby Aged to perfection! Rover 75 Conn SE Tourer Join Date: Nov 2006 Location: Princes Risborough Posts: 639 Thanks: 405 Thanked 423 Times in 226 Posts	Sounds like an injector fuelling problem imho. Try a tank full of Forte Advanced diesel treatment to clean the system through as it might just be a simple issue of a dirty or sticking injector. Or you could try a leak back test which would identify a duff injector __________________ Nobby....... Sometimes I talk to myself, Then we both LAUGH!