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Old 8th November 2017, 08:27 PM
B4-Andy B4-Andy is offline
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Default Throttle Potentiometer

So brief bit of a story before the problem. The Mrs is out in the S8, she phoneds me a bit panicked and shook. She says there’s something wrong with the wheels on the car, it was skidding. Ok, so were you going fast. No. Ok. I’ll check it. This is after I have stuck the winter wheels back on which are obviously a bit narrower. A lot narrower. Anyway the pressures were a bit off, got that fixed and discovered that yes, it gets a bit slidy - at 50 on a roundabout. Goes back and explains that perhaps she’s got used to driving around far too fast, she says “well there was this Golf sitting too close and annoying me”... I stopped her right there.

Anyway it got me thinking, the throttle response on this motor has always been a bit jumpy - which may have brought on a slide a bit sharper. I put that down to the automatic and the powerful engine at first but now I’m thinking that perhaps the throttle potentiometer has worn down near the start of the pedal travel. I did read that these were early fly by wire motors, and normally the early ones had pot’s instead of hall sensors.

Anyone else had this / replaced theirs / had their Mrs turn into a rally driver overnight?

Last edited by B4-Andy; 8th November 2017 at 08:28 PM. Reason: Clarification.
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Old 8th November 2017, 08:49 PM
HPsauce HPsauce is offline
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All sorts of reasons for that. In my case after suspecting the throttle, MAF, F125 switch (which was dodgy) and many other things, it turned out to be mainly a mis-adjusted brake pedal switch!

If you do want a throttle potentiometer I have a spare that I never fitted. Bought used from our sponsors.

It's still pretty kangaroo-like when first driving off from a cold start, but settles down quickly. Not sure if that's to do with the SAI system.
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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; 8th November 2017 at 08:52 PM.
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Old 8th November 2017, 09:03 PM
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briang9 briang9 is offline
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Sounds more like your wife's driving style IMHO..however good luck with that one

Never had any issues no matter how hard I drive it. Also never mangaged to get it to slide except in snow.

Often on roundabouts there may be some diesel spill from buses, they are prone to filling them till they overflow I noticed, There is a corner near me that has caught a few drivers unaware and the theory amongst locals is it could be down to diesel spill.

In any case get her signed up for next years Monte Carlo..starts from Paisley I think
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Old 8th November 2017, 09:07 PM
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The_Laird The_Laird is offline
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I've had my D2 S8 (well, actually it's now David's S8) on a track on a performance car driving course and it didn't slide at all. But I do wonder what wheels and tyres you've got on as winter wheels, especially as you say that they're much narrower.
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Current mods: solar sun roof, 20mm rear spacers, 15 mm on front, red brembo callipers, 6k headlights, rear view camera, engine remap, alloy dash dial rings, alloy navi rings, tt/phaeton pedal upgrade, (and custom matching foot rest) dension ipod interface & parrot hands free kit (both fully hidden), av input, tv in motion switched thro' PF switch in blanking plug right of steering column, Audi 'quattro' sill covers, repositioned centre console switches, radio clock, .
Planned mods: auto-dimming rear view mirror, dash cam (as steamship's), fit the ski hatch, refit philips drl's (or maybe not - nope, definitely not - horrible botch!).
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Old 8th November 2017, 09:08 PM
B4-Andy B4-Andy is offline
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Brake pedal switch!? What's that got to do with accelerating? Sometimes motors are bizarre!

I'm fairly certain it's not gearbox related, when you try to pull away smoothly you have to treat the pedal like a Fabergé egg, there's a very definite point where you press the pedal beyond and there's a sharp rise in power, leading me to believe it's worn. The jump is less noticeable at speed but still there.
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Old 8th November 2017, 09:11 PM
HPsauce HPsauce is offline
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Quote:
Originally Posted by B4-Andy View Post
Brake pedal switch!? What's that got to do with accelerating?
After releasing it to drive off it sticks in a position (there are actually two separate switches) where the brakes lights are off but the ECUs think the pedal is still pressed, limiting engine power despite a heavy right foot.
Then, vibration or whatever makes the pedal lift a tiny bit more, brakes are now seen as off and the ECU says - OFF YOU GO! Wham!

I was able to prove that on mine by monitoring the switches with VCDS and adjusting the stop (just a twist but PITA to get at!) until they accurately reflected my foot on the pedal.
__________________
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; 8th November 2017 at 09:14 PM.
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Old 8th November 2017, 09:11 PM
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briang9 briang9 is offline
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Just a thought..does she drive with it in "S" mode, that does seem to make the throttle response more "immediate"...
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  #8  
Old 8th November 2017, 09:11 PM
B4-Andy B4-Andy is offline
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It's 18" Avus from an A/S6 - Not sure of width and it's too cold to go out and see!

The jumpy throttle and higher speed is the reason I think it slid, well when I say slid, squirmed. I had to be pushing it mid-corner to get it to go, so completely expected, but a bit disconcerting for her.
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Old 8th November 2017, 09:20 PM
HPsauce HPsauce is offline
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Quote:
Originally Posted by B4-Andy View Post
It's 18" Avus from an A/S6
They should be fine, but what tyres are they?
__________________
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!
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  #10  
Old 8th November 2017, 09:28 PM
B4-Andy B4-Andy is offline
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I may be talking crap, looks like they are the same width. Dunlop SP Winter Sport 3D, the summers are Conti Pilot Sport affairs.

Then again it has been icy here and damp on the road and quattro doesn't make it invincible!

Last edited by B4-Andy; 8th November 2017 at 09:36 PM.
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