PDA

View Full Version : Rough running TD5 at low revs.


worane
22nd March 2018, 09:04 PM
I have been chasing a rough running patch just above idle (about 800 to 900 RPM.) . It seems to disappear as the revs rise, or gets hidden in the noise of a diesel though there is no roughness above 1k.rpm.
I am looking at this as a part of an appraisal of vibrations all the way up to 100 kms.
I have removed the rear prop shaft and I thought the vibrations had disappeared but I drove it again this morning only to realise though they are not as obvious as they were with the rear shaft in place (quieter) they are still there. Must be a case of harmonics.
The front shaft is new the transfer case and centre diff have just been rebuilt. the doughnut is also new.
Does any one have any ideas on the rough running at low revs? Or any other useful comments please?
The motor has done about 190k.
donh54
22nd March 2018, 09:17 PM
Auto or manual? If manual, could be related to the dual-mass flywheel.
Is this roughness while you are driving, or is it there also in neutral?
If it's there when you're driving, does it vary if you are accelerating or decelerating?
Do you have a diagnostic tool that can read the injector values?
Has it always done this, or is it only since some of the work has been done?
worane
22nd March 2018, 10:29 PM
Auto 1999 td5 has done it since I put the motor in @150 k.
Only feel it between 800 to 950 rpm
Vibrates all the way when it is being driven. It is like it is on small corrugations.
Injectors all ok by nanocom. Ambient air sensor suspect and often shows as a fault.Have replacement on order .
harro
23rd March 2018, 07:58 AM
Auto 1999 td5 has done it since I put the motor in @150 k.
Only feel it between 800 to 950 rpm
Vibrates all the way when it is being driven. It is like it is on small corrugations.
Injectors all ok by nanocom. Ambient air sensor suspect and often shows as a fault.Have replacement on order .


Disconnect the aap sensor, the ecu will default to 100 Kpa (sea level). The engine will run fine.
this should let you know if it is the cause of your issue.
The aap sensor signal is part of the ecu boost calculation so does effect fuelling.

Paul.