Hi all, my S2 Avant has developed a missfire that only happens under full boost, dont think im getting boost cut its not violent enough more of a hessitation and runs fine under any other driving conditions, so had a look around and found 3 of the 5 coil packs have cracks in the plastic bodys, could this cause a missfire?
missfire
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One missing and hesitation diagnostic
Typically misses at high boost levels = weak coils, unable to produce the needed spark under pressure (literally). Solution = find the weak coil(s) and replace with new. Here is a link that provides some methods to check your coils for weak spark.
One missing and hesitation diagnostic:
RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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First you need to get the terminology right.
Do you have coils like these OE ones:
(More coil info: http://forums.quattroworld.com/s4s6/msgs/4088.phtml )


or these coilpacks:
Last edited by UrS4boy; 29 September 2013, 17:45.RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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Coils can be bought from gsf for £70 quid each....either replace all 5 or do what i did and replace one at a time till the fault goes away. Splice wiring into loom just outside of coilpack cover and get some good quality crimps and heat shrink
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I was looking for but couldn't immediately find this photo of the OE coils and OE boots being pulled from a cam cover that has a failed cam cover center gasket. (By the way, this kind of failure does NOT cause missing because oil is not an electrical conductor - but it will kill/eat those rubber coil-to-plug boots):
RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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