Just bought a 20V Quattro Coupe (7A) and power backs off intermittantly when accelerating or holding 70+ MPH. Makes overtaking very unpredictable as it decides to randomly switch between scalded cat and driving Miss Daisy modes. Gets worse, the longer you drive it. ECU is showing no faults and 2 Audi 'specialists' have not been unable to find the fault. Any ideas? Anyone experienced similar?
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85' 80 Sport, 90' Coupe 2.3E, 90' 2.3 20V Coupe Quattro, 93' 80 Avant 2.6 SE, 95' A6 Avant 2.5 TDi Se, 98' A6 1.9 TDi SE, 95 S2 Avant -
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You mean it feels like a 'turbo' just kicked in them just drops out randomly...knock sensor was my problem.
There's 2 fitted on these, mine did show up as fault code.Carlos.
On the look out for less bits for my s2 saloon project. Now supporting myself by shooting for my food. www.airgunforum.co.uk -
2nd that, i didn't get any error codes but had the same symptoms.91CQ20v - Gone to a new home
93UR-S4 - The Magic Carpet
94S2Bus - The Emerald ExpressComment
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Genius! Thanks all. Spot on. Yes it does feel like a change in turbo boost on acceleration, and yes the only error was the knock sensor. However, both 'experts' claimed it was quite normal for the diags to show up the knock sensor. If there are two on a 7A, please can you let me know where I can find them and if there is any way of working out which one is at fault. I assume it is a relative no brainer to replace them? Thanks again.85' 80 Sport, 90' Coupe 2.3E, 90' 2.3 20V Coupe Quattro, 93' 80 Avant 2.6 SE, 95' A6 Avant 2.5 TDi Se, 98' A6 1.9 TDi SE, 95 S2 AvantComment
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Get a set from a breakers for £10 and replace both, S2 ones are about £25 each new as a guide.Cheers'en, AndyC
1994 ABY Coupe - Projekt AlpinweissComment
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Thanks. Found a 20V Coupe being broken by Audibits. Hope to bag both knock sensors & a few other bits.85' 80 Sport, 90' Coupe 2.3E, 90' 2.3 20V Coupe Quattro, 93' 80 Avant 2.6 SE, 95' A6 Avant 2.5 TDi Se, 98' A6 1.9 TDi SE, 95 S2 AvantComment
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Send a pm to stiglet on here or spink they should have them and probably better to deal with.
If you look straight on at the engine down the passenger side at the back is the knock sensors just infront of where the gearbox bolts on, they are held on with allen headed bolts and should only be 2x to remove possible 4 been a while since I removed them, you will see the wires coming out of the sensors and easy enough to swap around, just check the colour of the plugs (at the other end of the wires) before you change them.Comment
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The fault code will indicate if it is the front or rear sensor that is playing up, just fiddly to do.
Remember only tighten to 10Nm.
New price is more like £70 i think, where you getting your bits Andy?Carlos.
On the look out for less bits for my s2 saloon project. Now supporting myself by shooting for my food. www.airgunforum.co.ukComment
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You should find as the knock sensors get worse the problem can be temporarily solved by switching the ignition off and on again.
As Carlos says the code will tell you which sensor is at fault. 2142 for #1 (front), 2144 for #2 (rear).
IIRC the bst way to get to the senosrs is to lift the PAS pump out of the way for knock sensor 1, and the FPR for sensor 2. But it was a long time ago I did the job on a 7A.
HTHSSComment
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Here...
Are 7A, S2' S interchangeable, dont think so...
Carlos.
On the look out for less bits for my s2 saloon project. Now supporting myself by shooting for my food. www.airgunforum.co.ukComment
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Nope. 7As use Hitachi knock sensors, 3Bs are Bosch.SSComment
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