A8 Parts Forum  

Go Back   A8 Parts Forum > A8 D2 > D2 - Everything else

D2 - Everything else Anything that doesnt fit elsewhere

Reply
 
Thread Tools Display Modes
  #1  
Old 14th February 2013, 06:01 PM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default Erratic throttle response when cold

I'm still trying to get a good feel for what goes on and when, but this is what I've noticed so far - more than once in each case:

1. Driving away from my house when starting the car from cold usually involves reversing out then driving off uphill, a definite hill but not especially steep.
I've noticed the car surging then slowing then surging forward again without me changing the position of my right foot. "Kangaroo petrol"
(I may have experienced this elsewhere but not 100% sure as I'm usually driving away gently on level ground)

2. Pulling out of a side road and accelerating the car only speeds up "gently" not "urgently" as I expect. No ABS/ESP warnings or symptoms. Only seen within the first minute or so of driving the car and not always by any means.

I haven't yet tried starting it on the drive and gently pressing the accelerator pedal to see if revs vary.

Problem #1 is a bit weird but #2 is potentially quite dangerous.

No codes showing on VCDS. No "slipping" or increased revs, just varying power so I suspect engine-related not gearbox.

It's an FL S8 which I understand is "fly-by-wire" though what the relevant components are and where I don't know.

Suggestions please on possible causes and how to diagnose.
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!

Last edited by HPsauce; 14th February 2013 at 06:04 PM.
Reply With Quote
  #2  
Old 14th February 2013, 08:16 PM
Architex_mA8tey's Avatar
Architex_mA8tey Architex_mA8tey is offline
Moderator
 
Join Date: Jan 2009
Location: London/Oxford/Swindon
Posts: 7,648
Default

have you checked that your manifold flaps and actuators aren't sticking and are operating properly? just a thought. . .
__________________

Confidence is the feeling you have before you know better . . . .
Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange
2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee
20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble
Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior
Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble
Audi A8L D2 4.2 Petrol with LPG - Ebony Black
Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black
Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior
and some other A8's A8L's and Mercs
Reply With Quote
  #3  
Old 14th February 2013, 08:20 PM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default

Pretty sure, I checked the other day (as noted somewhere here when I first got similar symptoms) and the links are definitely connected properly and the vacuum units operate as they should.

What can you check easily other than position when off and when started - they certainly move instantly.
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
Reply With Quote
  #4  
Old 22nd March 2013, 10:55 AM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default

A little more input on this problem.
It's been suggested that it might be a temperature sensor somewhere playing up and causing under-fuelling, so to try just leaving the car to idle and warm up somewhat before driving off. Then when it's cold again plug in VCDS and look for suspicious readings.

Did the idle warm-up this morning not touching the pedal, letting the needle move to about 60C before driving off; it behaved perfectly.

Though I have VCDS I wouldn't know where to start looking for sensors that can be checked, or which ones are likely culprits? Help!
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
Reply With Quote
  #5  
Old 22nd March 2013, 04:10 PM
ainarssems ainarssems is offline
Senior Member
 
Join Date: Aug 2010
Location: Rushden, Northants
Posts: 3,799
Default

Check engine temperature when it's cold if it shows much more them ambient the clearly it is wrong.
__________________
Currently 8less
2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D

8 history:
2006 A8 Sport 4.2TDI quattro SOLD,
1997 S8, reached end of life with gearbox failure
Reply With Quote
  #6  
Old 22nd March 2013, 04:13 PM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default

Well yes, but apart from the gauge on the dash (which seems to operate normally and has 50C at the bottom) where would I go (in VCDS?) for a more accurate figure?
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
Reply With Quote
  #7  
Old 22nd March 2013, 05:26 PM
ainarssems ainarssems is offline
Senior Member
 
Join Date: Aug 2010
Location: Rushden, Northants
Posts: 3,799
Default

Measuring blocks and cycle through the channels to see different readings
__________________
Currently 8less
2011 Q7 S Line 3.0TDI, 2016 Tesla Model S 90D

8 history:
2006 A8 Sport 4.2TDI quattro SOLD,
1997 S8, reached end of life with gearbox failure
Reply With Quote
  #8  
Old 22nd March 2013, 05:57 PM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default

OK, I'm with you, didn't realise it would explain what the measurements were. Haven't explored VCDS much so I'm a novice.

Did that and found nothing that looked odd, temp 15C about 3 hours after last use in 3C ambient which seems very plausible.

Started the engine and watched various measurements as it warmed up; again nothing looked odd to my inexperienced eyes. Though it did feel a bit "lumpy" when I revved it up to get it warm.

I think I might need to set it up to graph the throttle position among other things and go for a drive (with an assistant).
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
Reply With Quote
  #9  
Old 22nd April 2013, 05:27 PM
HPsauce HPsauce is offline
Senior Member
 
Join Date: Sep 2011
Location: Chilterns, almost over HS2!
Posts: 8,366
Default

Any further thoughts anyone on a systematic way to investigate this and nail it down? It's getting annoying.

I went for a short drive yesterday, starting off by "pootling" down the road (250yds downhill) and turning left into the main road at the bottom.
Luckily it's only a 30mph limit as at the first attempt it just dawdled, so I didn't pull out.
Second go a few seconds later was fine and I then turned on cruise control for most of my journey which is in a 50mph limit.
After a 2-mile drive it was parked for maybe 30-40 minutes then started up and driven home - no dramas at all, behaved normally.

Checked codes today and there's only the intermittent 01119 Gear Recognition Signal problem in ABS (03). Could that be in any way related?
__________________
2003 D2 FL S8. Irish Green Pearl/Beige. Solar sunroof, auto-dim mirrors, electric rear seat functions, ski hatch retrofit; extended leather. Aftermarket DVB-T, reversing camera and full XCarlink (Bluetooth etc.).
2016 Volvo V40 T5 Cross Country (4WD) with ALL the toys including adaptive cruise etc. etc. Osmium Grey with Blonde/Charcoal leather interior. Polestar performance "optimisation". (A much rarer model than a D2 S8 by the way!) Oh, and a brand new engine at just under 30,000 miles on the factory one!
Finally: gone, but not forgotten.....
1998 D2 PF S8. AgateGrey/Platinum. Every option (I think) except electric rear seats, tiptronic steering wheel, ski hatch, towbar & dimming door mirrors.
e.g. Cruise control, NavPlus/TV, Bose, GSM, Xenons, Solar roof, Parking sensors, Alcantara/leather everywhere of course. (internal dimming mirror added later)
1998 (very early) Ford Focus 1.8 Zetec; ABS/TCS, Heated screen/mirrors, Aircon, Auto-dim mirror, Leather, Trip computer, Cruise control, OEM Ford SatNav with CD changer.
And before that a lot of Rover 800s, a few oddities, a lovely Triumph Dolomite 1850HL with Overdrive and way back in my schooldays an Austin Seven aka Mini 850!
Reply With Quote
  #10  
Old 22nd April 2013, 05:45 PM
Architex_mA8tey's Avatar
Architex_mA8tey Architex_mA8tey is offline
Moderator
 
Join Date: Jan 2009
Location: London/Oxford/Swindon
Posts: 7,648
Default

are all the breather pipes in good order and not leaking anywhere? just a thought as it sometimes causes lumpy running etc. . .
__________________

Confidence is the feeling you have before you know better . . . .
Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange
2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee
20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble
Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior
Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble
Audi A8L D2 4.2 Petrol with LPG - Ebony Black
Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black
Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior
and some other A8's A8L's and Mercs
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 03:34 PM.


Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.