XUD knocking intermittently
Hello guys,
I recently did the fuel pump seals on my 406. there was a co ck up when removing the cam belt and the crank was turned whilst trying to undo the crank pulley bolt. The belt was already off at this time.
upon putting the new belt on and doing two turns of the engine by hand it stopped, assuming maybe pump problem but found the crank was out of sync. Set it all back up and all was well. The car infact seemed to go like stink. Ive done 250 miles in the last few days and as of this morning something on the engine is making that noisy diesel knock/rattle. the rev counter also stopped. I turned the engine off and bumped it going down a hill. The engine went back to normal as did the rev counter.
Could I have bent a valve when doing doing two turns by hand? I thought maybe an injector?
The pump was removed from the engine whilst seals were replaced, immobilizer was also removed and hardwired.
Any thoughts would be greatly appreciated
James
XUD knocking intermittently
Moderator: RichardW
- CitroJim
- A very naughty boy
- Posts: 49620
- Joined: 30 Apr 2005, 23:33
- Location: Paggers
- My Cars: Bluebell the AX, Polly the C3 Picasso, Pix the Nissan Pixo, Propel the duathlon bike, TCR Pro the road bike and Fuji the TT bike...
- x 6182
- Contact:
Nope,
Rest happy James.
The rev counter gives it away.. You lost the signal either from your Needle Lift Sensor or your TDC Sensor, more likely the former... Loss of the signal will upset the timing control and lead to knocking...
Check the security of the Needle Lift Sensor plug as a fiirst start.
If there was any valve damage, the knock would be constant...
Rest happy James.
The rev counter gives it away.. You lost the signal either from your Needle Lift Sensor or your TDC Sensor, more likely the former... Loss of the signal will upset the timing control and lead to knocking...
Check the security of the Needle Lift Sensor plug as a fiirst start.
If there was any valve damage, the knock would be constant...
Jim
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
-
- Posts: 328
- Joined: 10 Apr 2009, 23:34
- Location:
- My Cars:
^^^ As Jim says
A colleagues Xantia became intermittently very knocky. That was due to a failed needle lift sensor.
It's probably not related, but years ago my wife's Audi 80 TDI started suffering from fuel starvation. It was fine around town but on the motorway it would cut out and then run again.
It turned out that one of the overflow pipes had split (the small rubber ones that run between the injectors and back to the pump). Then the needle lift sensor packed up as well. I assume that the lack of diesel intermittently caused the needle lift sensor to fail.
A colleagues Xantia became intermittently very knocky. That was due to a failed needle lift sensor.
It's probably not related, but years ago my wife's Audi 80 TDI started suffering from fuel starvation. It was fine around town but on the motorway it would cut out and then run again.
It turned out that one of the overflow pipes had split (the small rubber ones that run between the injectors and back to the pump). Then the needle lift sensor packed up as well. I assume that the lack of diesel intermittently caused the needle lift sensor to fail.
-
- Moderating Team
- Posts: 11575
- Joined: 02 Apr 2005, 16:11
- Location: Charmouth,Dorset
- My Cars: Currently:
C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red
In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars. - x 1205
Unfortunately, yes. The TDC sensor is on the n/s end of the engine just below the head and above the flywheel, not very easy to get at, you should be able to see the connector though, a small two or three pin plug, these can cause intermittent signal, take it apart and squirt some WD40 into it.
Peter
Peter
Right guys,
I sprayed WD40 into all the connectors the night before last. I did it to all the ones connected to the fuel pump, the lift sensor and what I thought was the TDC sensor. I checked the connector on the sensor above the clutch bell housing, which I thought was the TDC sensor and realised it wasnt a sensor just a blank with the connector plugged into it. Checked the other 406 and it looked the same.
I unplugged the needle lift sensor when it was running well and nothing happened, the rev counter stayed working ?!?!
Thanks
J
I sprayed WD40 into all the connectors the night before last. I did it to all the ones connected to the fuel pump, the lift sensor and what I thought was the TDC sensor. I checked the connector on the sensor above the clutch bell housing, which I thought was the TDC sensor and realised it wasnt a sensor just a blank with the connector plugged into it. Checked the other 406 and it looked the same.
I unplugged the needle lift sensor when it was running well and nothing happened, the rev counter stayed working ?!?!
Thanks
J
-
- Moderating Team
- Posts: 11575
- Joined: 02 Apr 2005, 16:11
- Location: Charmouth,Dorset
- My Cars: Currently:
C5 X7 VTR + Satnav Hdi estate Silver
C5 X7 VTR + Hdi Estate 2008 Red
In the past: 3, CX td Safaris and about 7, XM td estates. Lovely cars. - x 1205
The injector sensor won't affect the rev counter only the pump timing, the rev counter gets its signal from the TDC sensor. Its not very easy to get at there are usually wires and pipes in the way but if you can see the bottom of the cylinder head, the join where it fits on the block, the sensor is just below in the top of the gearbox housing.
Peter
Peter