Long story unfortunately but ultimately my PD170 has an annoying as hell vibration/drone that can be felt mainly through the pedals & steering wheel starting at around 1400rpm all the way to 1800rpm before it disappears. Either side of this RPM range the engine & ride is smooth as silk with no noise or vibrations.
Originally it was thought that it was the air intake pipework resonating & causing this noise, however it is back with a vengenece despite the pipework being padded with foam, felt tape, & rubber washers/isolaters on every possible screw fixing, & it's now looking like the pipework vibration was a result of, rather than the cause of this issue.
Since last year (thanks to an almighty Audi dealer balls up) the car has had a complete new cylinder head, new turbo, & new injectors, all of which have been checked for correct adjustment & are all ok. Annoyingly the vibration seems to start exactly in the rev range where the injector balance switches off/phases out, but even after looking at the inj balance at idle it doesn't show anything being out of whack (see image below), in fact it seems to be running very well balanced indeed.
Before anyone starts mentioning the DMF I have to say that I have no chatter, no slipping, no rattles, or knocking coming from the transmission or clutch, there is a slight pulsing in the clutch pedal when lightly pushed which is quite normal but beyond that everything else seems 100%. When the vibration is felt through the pedal it can be felt through all 3 of them (not just the clutch) & is almost a very high frequency 'buzz' but with a very deep drone sound. No difference is made with the clutch pedal depressed or released & the vibration noise will still be produced at the same RPM range regardless. One thing of note is that the vibration/noise is better when the car is in gear & actually being driven although it is still present.
So far we've fitted/tried:
Complete new cylinder head
New Turbo
New Injectors
New Loom
Removing & padding the intake pipework
Removing the exhaust downpipe
Removing the engine covers & strapping down anything that looked remotely loose
Revving the car with the clutch in & out
Driving the car in gear at the exact RPM
None of the above has resolved or shown any reasons this issue so now Im utterly stumped & begging for help!
Originally it was thought that it was the air intake pipework resonating & causing this noise, however it is back with a vengenece despite the pipework being padded with foam, felt tape, & rubber washers/isolaters on every possible screw fixing, & it's now looking like the pipework vibration was a result of, rather than the cause of this issue.
Since last year (thanks to an almighty Audi dealer balls up) the car has had a complete new cylinder head, new turbo, & new injectors, all of which have been checked for correct adjustment & are all ok. Annoyingly the vibration seems to start exactly in the rev range where the injector balance switches off/phases out, but even after looking at the inj balance at idle it doesn't show anything being out of whack (see image below), in fact it seems to be running very well balanced indeed.
Before anyone starts mentioning the DMF I have to say that I have no chatter, no slipping, no rattles, or knocking coming from the transmission or clutch, there is a slight pulsing in the clutch pedal when lightly pushed which is quite normal but beyond that everything else seems 100%. When the vibration is felt through the pedal it can be felt through all 3 of them (not just the clutch) & is almost a very high frequency 'buzz' but with a very deep drone sound. No difference is made with the clutch pedal depressed or released & the vibration noise will still be produced at the same RPM range regardless. One thing of note is that the vibration/noise is better when the car is in gear & actually being driven although it is still present.
So far we've fitted/tried:
Complete new cylinder head
New Turbo
New Injectors
New Loom
Removing & padding the intake pipework
Removing the exhaust downpipe
Removing the engine covers & strapping down anything that looked remotely loose
Revving the car with the clutch in & out
Driving the car in gear at the exact RPM
None of the above has resolved or shown any reasons this issue so now Im utterly stumped & begging for help!
