A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D3 > D3 - Common Faults

D3 - Common Faults Quick links to all known common faults and their solutions

Reply
 
Thread Tools Display Modes
  #51  
Old 7th December 2017, 06:55 PM
North2007 North2007 is offline
Member
 
Join Date: Jul 2016
Location: Mid Ulster - Northern Ireland
Posts: 74
Default

Did you get it fixed Woody?
__________________
2003, A8 D3 4.0 TDI
Reply With Quote
  #52  
Old 11th December 2017, 02:18 PM
woodpoleman woodpoleman is offline
Member
 
Join Date: Sep 2012
Location: Nantwich, Cheshire
Posts: 32
Default

No not yet fixed.

Car gave up the ghost completely and was transported to local Audi. Didn't show anything on diagnostics, which was sent to Germany but still no joy. For no apparent reason car then started after a couple of weeks. Audi then cleaned earthing points and checked all fuses, relays and the starter motor.

Had the car back a couple of days when the fault reoccurred. It happened again last Friday. On both occasions it wouldn't start from a jump off a standing battery but started easily from a jump with the other vehicle engine running. Again on every occasion could hear the starter solenoid clicking but would only crank when the other vehicle engine was running. Don't know if this suggests the starter is breaking down and needs some extra oomph. Interestingly always starts from cold even this weather and starts from hot i.e. after a run stop and start again immediately but not when warm or the weather is hot.

Audi uninterested to offer any solution. Car is now with my other garage and told them if need be replace the starter motor.

Any thoughts out there will be most welcome. Can't believe this is the only A8 ever to do this!
__________________
Since new - 2005 (05) Akoya Silver 3.0 TDI Quattro everything standard except wheels. 145,000 miles.

Bought at 6 months old - Ming Blue 2001 (51) 2.8 Quattro Sport with Sat Nav. 122,000 miles

Bought at 2 years old - 1986 Nissan Silvia 1.8 ZX Turbo. 127,000 miles.

Reply With Quote
  #53  
Old 11th December 2017, 02:35 PM
North2007 North2007 is offline
Member
 
Join Date: Jul 2016
Location: Mid Ulster - Northern Ireland
Posts: 74
Default

An earth strap (starter) attaches to the outter side of the drivers chassis leg. Itís accessed by removing the inner guard in the wheel arch. The stud corrodes, and clamping washer needs to cleaned. I note audi say they have checked this, worth checking again.
__________________
2003, A8 D3 4.0 TDI
Reply With Quote
  #54  
Old 15th December 2017, 10:46 AM
woodpoleman woodpoleman is offline
Member
 
Join Date: Sep 2012
Location: Nantwich, Cheshire
Posts: 32
Default

Thanks I've fed this to my garage hope this is the answer. Much appreciated.
__________________
Since new - 2005 (05) Akoya Silver 3.0 TDI Quattro everything standard except wheels. 145,000 miles.

Bought at 6 months old - Ming Blue 2001 (51) 2.8 Quattro Sport with Sat Nav. 122,000 miles

Bought at 2 years old - 1986 Nissan Silvia 1.8 ZX Turbo. 127,000 miles.

Reply With Quote
  #55  
Old 3rd January 2018, 04:07 PM
woodpoleman woodpoleman is offline
Member
 
Join Date: Sep 2012
Location: Nantwich, Cheshire
Posts: 32
Default

Absolutely unbelievable!!! Car is now fixed.

It has taken 3 different garages (Audi main dealer 3 visits) plus 2 auto electricians 20 months to do what 30 years ago a car mechanic would have done in 20 minutes.

It was the starter motor and instead of a lag before cranking it's now trying to throw the engine out of the car.

Except for the final breakdown visit it always started when the breakdown truck used jump leads. I carried a spare fully charged battery but it would never start from a standing battery. The eureka moment was when I twice took a jump off a running running engine suggested it needed more voltage to kick into life.

Went back to garage No 3 and told them to check the earthing strap and if OK change the starter motor. It did the trick.
__________________
Since new - 2005 (05) Akoya Silver 3.0 TDI Quattro everything standard except wheels. 145,000 miles.

Bought at 6 months old - Ming Blue 2001 (51) 2.8 Quattro Sport with Sat Nav. 122,000 miles

Bought at 2 years old - 1986 Nissan Silvia 1.8 ZX Turbo. 127,000 miles.

Reply With Quote
  #56  
Old 3rd January 2018, 04:23 PM
North2007 North2007 is offline
Member
 
Join Date: Jul 2016
Location: Mid Ulster - Northern Ireland
Posts: 74
Default

Excellent, more helpful posts for us 8ers! Gave you back on the road.
__________________
2003, A8 D3 4.0 TDI
Reply With Quote
  #57  
Old 3rd January 2018, 08:37 PM
woodpoleman woodpoleman is offline
Member
 
Join Date: Sep 2012
Location: Nantwich, Cheshire
Posts: 32
Thumbs up

Thank you and everybody else who has offered suggestions and help. I hope the other guys with a similar fault get theirs fixed also.
__________________
Since new - 2005 (05) Akoya Silver 3.0 TDI Quattro everything standard except wheels. 145,000 miles.

Bought at 6 months old - Ming Blue 2001 (51) 2.8 Quattro Sport with Sat Nav. 122,000 miles

Bought at 2 years old - 1986 Nissan Silvia 1.8 ZX Turbo. 127,000 miles.

Reply With Quote
  #58  
Old 5th January 2018, 11:05 PM
H-M3 H-M3 is offline
Senior Member
 
Join Date: Feb 2016
Location: london
Posts: 860
Default

Glad to hear itís sorted buddy! Just out of interest, did the scan not pick up the starter motor?
__________________
A8L 3.0 TDI sport executive 2014.
Audi A2 1.4 petrol 2002

SOLD. Audi A8L 4.2TDI Silver 2006

Seat Ibiza 1.4tdi Eco 2008 Silver (£0 Tax)sold

NO VCDS rely on Neeldub
Reply With Quote
  #59  
Old 6th January 2018, 09:29 AM
woodpoleman woodpoleman is offline
Member
 
Join Date: Sep 2012
Location: Nantwich, Cheshire
Posts: 32
Default

Thanks.

Scanned multiple times by Enthusiasts, garages and Audi who even sent scan data to Germany, never picked up anything. Didn't stop the Entry & Start Authorisation (J518), Ignition Switch, Energy Management (J644) Control Units plus a Battery being changed out. Audi also confirmed the starter motor ok.

I'm a DIY enthusiast but my ability & knowledge stopped at rebuilding Rover 2000 TC engines, gearboxes in the 70's, Rover SD1 V8's from the 80's and Granada's in the 80's. I bowed to the greater knowledge of today's electronics since I can't argue with it until all else fails then maybe try some of the old school stuff.

Just pleased to get the fix. This forum was the most helpful with the document files and personal experience, which increased my knowledge immensely. Thanks again to all.
__________________
Since new - 2005 (05) Akoya Silver 3.0 TDI Quattro everything standard except wheels. 145,000 miles.

Bought at 6 months old - Ming Blue 2001 (51) 2.8 Quattro Sport with Sat Nav. 122,000 miles

Bought at 2 years old - 1986 Nissan Silvia 1.8 ZX Turbo. 127,000 miles.

Reply With Quote
  #60  
Old 6th January 2018, 02:31 PM
Mechcanico Lee Mechcanico Lee is offline
Senior Member
 
Join Date: Jul 2015
Location: St Helens Haydock
Posts: 434
Default

Happy you got it sorted in the end Woodpole man .

I see this kind of trouble every week ....multiple visits to garages , auto electricians, and vists to the dealerships , scans sent to Germany and so on ...

If the scan does not show it , if the ODIS /VAS test plan does not help load up the parts cannon and fire various items at it in a vague hope you may stumble on the problem , all at owner / customers expense of course .....dealerships are the worse in my experience

The scan will not show anything as the starter in itself is not under diagnostic scrutiny......yes it has battery monitoring module but at cranking amps levels itís of no use , could the battery monitoring module see a bad earth pathway , could it see a burned terminal , high resistance or frayed heavy cables a bad armature on a starter motor ....... not a chance .

If you have either a starter that does not crank over or cranks slowly or cranks slowly with no start or intermittent start , or delay before cranking what i would do is rig up a halogen bulb onto the starter solenoid terminal ...using a halogen bulb you can determine that the supply has some grunt behind it ,the bulb will pull out around 4 /5 Amps , next .....one channel of scope onto battery , second channel use a 1000 amp range inductive amps clamp around starter heavy cable

All sounds easy doesnít it ......but accessing a starter on newer cars can be a job in itself .... but to carry out the nessasary diagnostic pathway tests itís where you need to go Ď most folk will bail out at this point because well .... it just to arkward to get at and then revert to Ď guess a part Ď method .

So watching amps clamp and battery on scope channels ,and your halogen bulb .....crank it over ...... does bulb light ...if yes now watch scope channels ....if no wiring checks back to crank relay or module authorisation and so on .

So itís cranking over ......does scope show mega high amps starting peak and continues throughout extended cranking ....does battery volts stay around 10.5 volts under cranking ......this shows battery has got grunt behind it to keep pushing the high amps and holding the volts .....this shows battery is good , battery volts can drop a little more than the happy level though


Does battery volts drop considerably and amps drop away .....battery duff

Next volt drop testing on heavy cables or substitute heavy cables , is earth pathway good from starter to block or gearbox .... volt drop tests or substitute heavy leads with jump leads .

So all these tests carried out and starter is taking massive current to get it going and keep it going and battery volts a little low suspect starter motor ....or some kind of mechcanical resistance ....if vehicle runs well with no other symptoms ...loss of water etc. we can rule out other issues for mechcanical resistance .

Have this mantra ...... test not guess ..... if I fit part X or Y and it does not fix it then what ?? Rule out all other possibilities first and not after you have fitted part X or Y

Again happy you got to the bottom of it in the end 👍👍
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 12:41 AM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.