Anyone got knock sensor knowledge? I don't and need a bit of help!
I drove hundreds of miles today for a remap and within 5 minutes of getting there I was told cylinders 1 & 2 had excessive knock sensor voltages when revved and mapping wouldnt be worth it until this was rectified for the best results. I've run checks with VCDS myself now and can clearly see that cylinders 1 & 2 have higher voltages by a little at idle and considerably higher when revved to around 2-3k rpm.
It's hard to see just viewing the measuring blocks but a graph of the voltages shows clearly that cylinder 1 spikes very high when revved, cylinder 2 is a little less but still spikes high. Cylinders 3 & 4 are much lower with 3 being above 4 by a bit. Generally 1&2 are high, 3&4 are lower and seem 'normal'. Apparently it was only the voltages of 1&2 that are of concern.
I was informed the problem could be plugs, coil packs or coil pack wiring.
Plugs: They are 2 days old genuine VAG ones (part #101000063AA / NGK PFR6Q).
Coil packs: Bolt down ones.
I have tried the following:
Swapped 1 & 4 coil packs, cylinder 1 still spiking high, basically no change at all.
Then swapped plugs 1&4, basically no change, cylinder 2 briefly took over as the highest one but then it all went back to being the same.
Then swapped coil packs 2&3 - no change.
I then examined the wiring, it has been stripped apart before because it was taped with electrical tape and just seemed to have been opened and re-taped. However all insulation intact, no breaks, original connections (based on photos i've seen of others). Generally can't see anything wrong! Reassembled, all put back. No change. No noticable misfire or similar issues.
SO! Could it be the knock sensor on cylinders 1&2? I have been told that there are two and they triangulate the knock to work out individual cylinder values. I figured that the fact that almost always the voltages on the graph from top to bottom are cylinders 1,2,3 then 4 could indicate that the 1&2 sensor is reading high and throwing off all the values making the ECU think #1 is knocking really badly due to a vast imbalance between the two sensors which would, if they were balanced, indicate a #1 knock?
Anyway, enough rambling, anyone got any ideas? I'll post a pic of the graph when I get a chance to log another one.
I drove hundreds of miles today for a remap and within 5 minutes of getting there I was told cylinders 1 & 2 had excessive knock sensor voltages when revved and mapping wouldnt be worth it until this was rectified for the best results. I've run checks with VCDS myself now and can clearly see that cylinders 1 & 2 have higher voltages by a little at idle and considerably higher when revved to around 2-3k rpm.
It's hard to see just viewing the measuring blocks but a graph of the voltages shows clearly that cylinder 1 spikes very high when revved, cylinder 2 is a little less but still spikes high. Cylinders 3 & 4 are much lower with 3 being above 4 by a bit. Generally 1&2 are high, 3&4 are lower and seem 'normal'. Apparently it was only the voltages of 1&2 that are of concern.
I was informed the problem could be plugs, coil packs or coil pack wiring.
Plugs: They are 2 days old genuine VAG ones (part #101000063AA / NGK PFR6Q).
Coil packs: Bolt down ones.
I have tried the following:
Swapped 1 & 4 coil packs, cylinder 1 still spiking high, basically no change at all.
Then swapped plugs 1&4, basically no change, cylinder 2 briefly took over as the highest one but then it all went back to being the same.
Then swapped coil packs 2&3 - no change.
I then examined the wiring, it has been stripped apart before because it was taped with electrical tape and just seemed to have been opened and re-taped. However all insulation intact, no breaks, original connections (based on photos i've seen of others). Generally can't see anything wrong! Reassembled, all put back. No change. No noticable misfire or similar issues.
SO! Could it be the knock sensor on cylinders 1&2? I have been told that there are two and they triangulate the knock to work out individual cylinder values. I figured that the fact that almost always the voltages on the graph from top to bottom are cylinders 1,2,3 then 4 could indicate that the 1&2 sensor is reading high and throwing off all the values making the ECU think #1 is knocking really badly due to a vast imbalance between the two sensors which would, if they were balanced, indicate a #1 knock?
Anyway, enough rambling, anyone got any ideas? I'll post a pic of the graph when I get a chance to log another one.
