#1
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knock sensor plug pigtail
The knock sensor plug pigtail looks to be disintegrating.
I have only done a general visual inspection of everything I can see in the engine room while I have removed all the plastic covers. But from what I understand looking through old threads where MJ shows photos and comments, it is something better left untouched? I looked at one of your photos MJ, with the manifold removed. No way I can get to that. By the way, I do not have two green knock sensors, but one green and one orange. *I hope I use the correct words for the parts. I could find knock sensor cables in online shops, but not the plug pigtail*
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Johannes _________ Audi S8 -99, Pearlescent, Alcantara/silk napa leather, Burr walnut insert, Alcantara roof lining upper pack A8 32V engine ----- Jeep Grand Cherokee -98 |
#2
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Araldite?
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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! |
#3
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Interesting suggestion, would that work? On the other hand it would look pretty awful, I fear.
But it might be the only option. As I cannot risk removing the manifold and drop some dirt into the engine
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Johannes _________ Audi S8 -99, Pearlescent, Alcantara/silk napa leather, Burr walnut insert, Alcantara roof lining upper pack A8 32V engine ----- Jeep Grand Cherokee -98 |
#4
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I had both of my knock sensors replaced a while ago. One of the plugs had disintegrated just like yours so I suspect it's a common issue. From memory, the sensors weren't too expensive and came complete with new leads and plugs.
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Mark ------------------------------------------------------ 2002 FE S8 Ebony Black Pearl ------------------------------------------------------ ------------------------------------------------------ Cars Owned: The Tesla Era: 2020 Model S Performance Ludicrous+ (present) (Black, with all black premium interior and carbon fibre décor, 21" sonic carbon twin turbine wheels and FSD capability) The Audi Era: '97 A8 4.2 (Ming Blue) --> '96 A8 4.2 QS (Dark Green) --> '02 FE S8 (present) The Citroen Era: '84 BX 1.6 RS --> '89 BX 1.9 DTR Turbo --> '94 XM 2.0L Turbo --> '96 XM 2.0L Turbo Exclusive --> '00 Xantia Activa 2.0L Turbo The Banger Era: '76 1.2L Lada VAZ-2101 (Ruski Fiat 124) --> '80 1.7L Morris Ital HL, finished in Ermine White and Rust |
#5
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Yes, it is a common problem. Somehow Bosch managed to make the connectors from a plastic which doesn't survive the heat of an engine bay
You can't just replace the connector unfortunately. Its a screened cable which is very difficult to work with. The connector colour denotes the cable length by the way. Tbh if taking the manifold off is not an option I would be inclined to go with Andrew's suggestion of an adhesive product to hold the connector together. Yes, it has a high risk of looking fairly awful, but thats really all you can do with the green one. The brown one is on the outside of the V though, behind the power steering pump, so that can be changed without too much difficulty. |
#6
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Normal "domestic" Araldite is nominally only rated up to 65C, but would probably be OK. I'd probably risk it on my own car.
Better to find a 2-part epoxy adhesive rated for a higher temperature as the engine bay will normally be over 110C; there are loads available, Araldite themselves have a huge range. Or look at UV-cured adhesives, again a wide choice. I've used Bondic which I think is OK up to 150C; it's also clear and easy to build up so can be tidy.
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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; 30th June 2020 at 03:21 PM. |
#7
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Thank you for all your comments. I see my options might not be set in stone, especially since Mark had his replaced without any issues.
I won't try to remove the manifold myself, as that would end in disaster, I am sure
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Johannes _________ Audi S8 -99, Pearlescent, Alcantara/silk napa leather, Burr walnut insert, Alcantara roof lining upper pack A8 32V engine ----- Jeep Grand Cherokee -98 |
#8
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Quote:
Apart from the broken connector and an intermittent knock sensor fault, one of the reasons I decided to get the job done was because I had some oil leakage and fumes coming from under the inlet manifold (plus I wanted to fit a spare new manifold that I'd purchased some years ago). The leak was caused by a failed gasket on the cover that sits in the 'valley' of the Vee (whatever it's called?). If your valley cover gasket has never been changed, it's likely it'll be very oily and gunky under there like mine was, so it's probably worthwhile lifting the manifold off just to replace the gasket and remove all the gunk.
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Mark ------------------------------------------------------ 2002 FE S8 Ebony Black Pearl ------------------------------------------------------ ------------------------------------------------------ Cars Owned: The Tesla Era: 2020 Model S Performance Ludicrous+ (present) (Black, with all black premium interior and carbon fibre décor, 21" sonic carbon twin turbine wheels and FSD capability) The Audi Era: '97 A8 4.2 (Ming Blue) --> '96 A8 4.2 QS (Dark Green) --> '02 FE S8 (present) The Citroen Era: '84 BX 1.6 RS --> '89 BX 1.9 DTR Turbo --> '94 XM 2.0L Turbo --> '96 XM 2.0L Turbo Exclusive --> '00 Xantia Activa 2.0L Turbo The Banger Era: '76 1.2L Lada VAZ-2101 (Ruski Fiat 124) --> '80 1.7L Morris Ital HL, finished in Ermine White and Rust |
#9
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Mark,
How did you determine a knock sensor fault? Did it show on diagnostics, or did you have pinging? I ask, as I get pinging from the S8 under moderate load in 3rd gear acceleration (labouring engine). I also have cracking in at least one of the knock sensor plugs, and I've been wondering if one of them might be faulty? I only use 98RON and often add octane booster, especially for trips.
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Cheers Marty ____________________ Current: 2001 Audi S8 - Brilliant Black with Black interior, C5 RS6 rims (whenever I actually put them on...), Solar Sunroof, Tinted side and rear glass, RNS-D, Grom, Bose, clunky old phone in arm rest! 2002 Audi S8 - Project Replacement head coming arrived thanks to MJ Silver with Black interior. All features as the '01, with the 'S' mode auto shifter. Dodgey rear tint (need to find a way to get rid of that). Family: 2009 Volvo XC90 V8 R Design - has a louder more obnoxious exhaust than the S8, sounds great! Love this thing - Q7 was double the price, and certainly not double the car! Sold: 1997 Audi A4 - Hamilton's Club Sport, Achat Grey (will miss the old girl) |
#10
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I didn't notice any pinging but that could just be because my exhaust is so damn loud! Plus it was just an intermittent fault, which flagged a fault code, but only very occasionally. Unfortunately I don't appear to have kept a record of the fault code but, IIRC, it quite unambiguously pointed to the knock sensors.
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Mark ------------------------------------------------------ 2002 FE S8 Ebony Black Pearl ------------------------------------------------------ ------------------------------------------------------ Cars Owned: The Tesla Era: 2020 Model S Performance Ludicrous+ (present) (Black, with all black premium interior and carbon fibre décor, 21" sonic carbon twin turbine wheels and FSD capability) The Audi Era: '97 A8 4.2 (Ming Blue) --> '96 A8 4.2 QS (Dark Green) --> '02 FE S8 (present) The Citroen Era: '84 BX 1.6 RS --> '89 BX 1.9 DTR Turbo --> '94 XM 2.0L Turbo --> '96 XM 2.0L Turbo Exclusive --> '00 Xantia Activa 2.0L Turbo The Banger Era: '76 1.2L Lada VAZ-2101 (Ruski Fiat 124) --> '80 1.7L Morris Ital HL, finished in Ermine White and Rust |
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