Knock code again!!

[1.8quattro]

I was driving on the highway today, crusing under light load in 5th gear. I start going down a hill so I let off the gas. When I got back on the gas (barely feathering the throttle) I saw my CF's on block 020 shoot up to at least 8 on multiple cylinders for several seconds.

I checked my DTC's right away and I had this:

16712 P0328
Knock Sensor (KS) 1 -G61: High Input (sporadic)

I have been getting this same code more and more often lately. Sometimes I'll clear it and it won't pop up at least for another week or so.

There is nothing that looks evidently wrong when logging the other channels (my fuel trims are a bit high at about 5% and 15%). My CF's at WOT look better than those at part throttle. Vacumn at idle is around 21 inHg.

I can feel the car misfire when I get off the gas and apply part throttle sometimes. Besides this, if I weren't constantly logging I would not be able to tell anything is wrong.

Currently I know the car has a leaking rear coolant flange, a leaking valve cover gasket, and some coolant leaking around the drain plug (oil cooler gasket?). There's also a small 1-2psi boost leak somewhere...

Both knock sensors were replaced within the last year.

Here is the Ross Tech wiki page:
http://wiki.ross-tech.com/index.php/16712/P0328/000808

[AudiA4_20T]

your sensors were probably tightened too much and things that shouldnt be setting them off are

[1.8quattro]

Is block 020 affected by the knock sensor output?

[CO AVANT]

Torque wrenches can get out of calibration even if you are on your specified reading. One reason why I only buy craftsman now instead of the harbor freight Chinese crap. Always leave torque wrenches at their lowest setting when not in use (ie. 0ft/lbs). +2lbs either way can drastically change your readings through vag and sometimes it's hard to get dead on with a normal torque wrench sometimes. I recommend using a craftsman digital torque wrench to get more accurate readings.

They should be torqued at: 20nm or 14.751 lb/ft

[1.8quattro]

Would over tightening the knock sensors affect the CF's? Are the large CF numbers I'm seeing due to over-torqued sensors?

Also, say the sensors are properly torqued...what else could this be?

[CO AVANT]

Over-tightening the knock sensors will mess your cf's up and also your knock voltages. I'm sure there are many more things in the system that the domino effect will come into place then. Would have to sit down and think about what those could be though...

[1.8quattro]

OK thanks CO Avant. I know the car isn't knocking, I'm pretty sure I would be able to notice that much.

I was looking at my knock voltages the other day while driving and two of the values were peaking somewhere around 11V. The strange thing was the other two were about half as much. I thought all four readings would be about the same?

Are these sensors easy to get to?

[CO AVANT]

No they are not always the same. Be glad you are not maxing out at ~29V like I was. I blame it on my old solid engine mounts. The sensors are kind of a PITA to get to. Definitely need an extension. The one behind and below the oil filter you can get to. The one behind the alternator might be a bitch. Might have to take some stuff off to get to it.

[dougyfresh]

What engine mounts are you using now Jordan? I'm going with some 034 street density mounts.

[CO AVANT]

What engine mounts are you using now Jordan? I'm going with some 034 street density mounts.

Same

[1.8quattro]

It happened again this morning, exact same situation. Such a PITA! And this was running on the "stock" program, just for kicks.

[1.8quattro]

OK, so I had the torque checked on both sensors and they were a bit loose. The car seemed to be fine driving around town, my CF's looked very good, small peaks but then down to zero on WOT.

Today I was driving on the highway and I had the same exact problem again. It seemed like the CF's shot and held at a constant 8.2 while I was feathering the throttle down a hill. I have the same code again. However I can drive around all day in full boost and my CF's are zero. I have the code but no CEL. Eventually if I don't clear the code I will get a solid CEL.

Any ideas? Both sensors are less than a year old, so I doubt those are the problem.

[AudiA4_20T]

hmm well you said you found it odd that 2 of the cylinders were fine and the other 2 werent, but thats because theres 1 sensor for each 2 cylinders, so that makes sense...

Is the code still there for the knock sensors? or are your CFs just high now?

[1.8quattro]

I have the same P0328 code as in my OP. My CF's are just fine driving around town and in full boost (zero). This problem just seems to happen driving on the highway, under very light load.

Knock sensor voltages: I'm not sure how to interpret those. Two values were about twice as high as the other two. I didn't check how these have changed since I've had the sensors re-torqued.

[1.8quattro]

I was able to log blocks 020, 031, and 115 today. This was on the highway, fifth gear, low load. I know it's not the ideal log but it shows the problem. My CF's are peaking at exactly 8.2 on all four cylinders at exactly the same time.

http://spreadsheets.google.com/pub?k...-IYmYDRA&gid=0

I ran WOT a few minutes later and my CF's were all zero...go figure.

[1.8quattro]

No ideas? I know there's a bunch of smart guys on here somewhere.

Could this be an electrical issue? A short or a harness problem of some kind? It doesn't make any sense that all four cylinders have exactly the same correction at the same time.

[CO AVANT]

I would get a voltometer and test voltage and ohm readings on the wiring. I had a broken wire on my map sensor last year that I only determined was broken because I was getting 0 value on the voltometer. No way you could "see" it was broken otherwise. Ask Diagnosticator for voltage and ohm readings, he should know them...

[1.8quattro]

OK, thanks for the suggestion, I will keep that in mind.

I had the knock sensor replaced today since that was a relatively cheap fix, we are running down the list of things that could be causing this.

There was a major issue with my timing belt job, apparently my old shop botched it . Things were loose, my belt tensioner had a huge crack in it and was close to failure (timing belt done only 25k mi ago), among other things. Unfortunately though that does not seem to have solved the problem.

It seems that cylinders 3 and 4 tend to show retard before the others, so the cam tensioner was also brought up as a possibility? I'm keeping this as the last resort since it is quite a big fix.

[CO AVANT]

I had my cam tensioner replaced when BobQ rebuilt my motor. The cam fault codes I was getting before my engine failure last year were either caused by the cams or cam tensioner or a combo of both since they both had "issues"...

[1.8quattro]

Well replacing my knock sensor did absolutely nothing.

I guess my coilover fund is gone since I was quoted 6hrs labor + ~$600 for the cam tensioner replacement. Of course there's no certainty that will solve the problem either...

[1.8quattro]

bump...

Thanks CO_Avant and AUDIA4_20T.
Anyone else want to chime in?

This problem is bugging the hell out of me. It seems to happen completely randomly, CF's always shoot up from 0 to 8.2 on all cylinders, I have absolutely no other symptoms, no CEL, though I still have that same knock code.

One moment I can be driving at very low load and see a solid 8.2 deg retard, and maybe five minutes later I can be flooring it and CF's look completely normal.

[20vturbo]

check for something loose that may hit the block or anything thet may foul the sensors into thinking the car is knocking

[1.8quattro]

I am dropping off the car next week, I will have them check for anything loose. I couldn't spot anything.

If this were the case though wouldn't you see some variation in the readings? There must be some significance as to why all four cylinders show 8.2 deg (which isn't even the max?) at the same time.

[Nebone]

Any updates. I'm having the same code come up on my 2001 and the sensor has never been replaced. I fixed my lean condition and it is still occuring. All I see wrong with the car now is a faulty thermostat which stays open and does not let the car fully heat up. Thats next.