okay i think this thing is picking up false signals.
at idle its going from like 1-2 back and forth. on hotter days its up to 14??

and on the memory it said 109!
when i start driving it stays solid at 0.

 

Here's what you should have setup:
1. Karmen
2. 4cyl
3. the reading on mine was .615 fully closed and 4.855 fully open (pg 50 of manual)
4. Arrow goes up and to the right
5. Self explanatory
6. Start car
7. Page 38

 

Most people will tell you it's not that accurate. For the most part, readings < 50 or so probably aren't real "knock"...

Did you calibrate the knock? It's good to have the car really warm, like after a spirited drive, then you rev and hold the motor at ~1500 rpm and at ~3500 rpm and record the readings at each rpm. This sets up a baseline and should help minimize the false readings. On a hot day, I will see readings ~5-10 or so as well, but it's not a big deal. Even if it's not that accurate, I like to keep track of it.

Take care,

FB

 

It has nothing to do with reality. Look to see if your timing gets pulled... its really the only way, it sucks because you only know when you knock pretty hard.

 

Why wouldn't it, you calibrate the senson at certian rpm's after the car is warmed up, once you set that up it will read the voltage above it. The knock sensor reads from 0 to 5volts. Each car is different this is why you calibrate it but after that is done anything I would say 100>150 or so would be slight knock. The stock ecu uses the same thing but it samples at a certian time this is just a raw voltage so it can give you an indication.

 

If each car is so different why is the table on the ECU the exact same on each car? It is a joke and I would not recommend anyone to use as such.. I won't even hook it up because it technically will lower the voltage that the ECU sees by a tiny amount.. probably not enough to matter but who cares about a BS reading anyways? If you dont believe me just look at a datalog of your car and see when it pulls timing and see what the "knock values" read... they will never be the same. I have seen my knock sensor go nuts on one of my cars but the ECU doesnt read any knock. Its harder to explain how BS it is on the Evo because you can't ever see the knock that the ECU displays but trust me... its not right

 

Guys buy a "Knock Link" by Link - its cheap and dead accuarte . I would not drive a turbo car without it

 

The knock readings that you see on your data log I can't answer becuase I don't use one but I would suspect that it is just a raw value as well and it probably doesn't sample fast enought for you to even be able to see the real value. But like you said you can see timing got pulled so you can tell for sure. On an SAFC like you said it will not show you when timing got pulled but it will show the voltage spike or knock spike so atleast you know that somthing did happen right away because it holds the highest voltage recorded with realtime sampling. Usually if your car pulls timing very bad you can feel it. Neither source is perfectily accurante on the knock reading as far is how the ECU measures it becuase the ECU probably measures it only at the time of ignition and not just all the time. The datalog method is probaby better in you respect being able to know exactly wether it was pulled or not but the SAFC sensor does read knock volts so it can atleast let you know if you are safe or not. IE for example If you see large differences after you make a change so it will give you some sense of what your changes did. Please be aware to see the ecu actually pull timing is better without a doubt but I am also saying that the knock reading on the SAFC isn't totall useless if they are setup right. This is just my opinion from the experience that I have had with them. Each car does have a different noise trend though, one car will be noisier than the other via knock readings before knock actually happens and I cant say exactly how the stock ecu measures that but I am sure in a safer respect so they might all be the same, I don't think anyone knows exactly for sure.
I hope this makes it easier to understand my point

 

I have never used the knock link before but given your car I believe it works The AFC knock reading is a good idea but just doesn't really work. The ECU is as realtime as it gets though as far as DSM datalogging... think, the AFC gets its info from the same wires the ECU does... It would be much better if they made the AFC so you could actually set the voltage thresholds to where you want. I dont really know why they have that "auto-sense" bs. The knock sensor does just **** out voltage based upon noise tuned to a certain frequency... the problem is the more RPM your motor hits, the more noise, the more voltage... that is where a table would come in. The table would set a threshold at certain RPM's vs. certain voltages. That is how the EMS works and your stock ECU. Im sure given enough time and effort you could make an AFC tuned correctly to your knock sensor... but by that time it would have been more cost effective to find another solution (Like buying the knock link?). Like I said, OBD-II sucks because you can't read the knock and all you see if the timing being pulled. Personally... if I am knock bad enough for my timing to be pulled I will be scared ****less but that is what most people are forced to do... except of course the AFC tuners that use that knock sensor reading. All they do is lean more and more out and look for that special knock number, who even knows what number correlates to what amount of ping or knock?? Oh well... like Dynoflash dude said, find a better solution. The AFC is not good enough for my $30k car

 

I would not trust it.

 

You do set a noise table threashold on the AFC at certian rpms. So it does measure anything above that. Not at just one RPM, we all know that the engine makes more noise at higher RPM. Like I said above in my statement it isn't worthless, this is the only point I was arguing but you keep betting it down, it reads from your stock knock sensor just like you said so its values do mean somthing. Think about it.

" the AFC gets its info from the same wires the ECU does" So does the data logger

"The knock sensor does just **** out voltage based upon noise tuned to a certain frequency... the problem is the more RPM your motor hits, the more noise, the more voltage... that is where a table would come in. The table would set a threshold at certain RPM's vs. certain voltages. That is how the EMS works and your stock ECU" I talked about this above you are right this is why set set it up on the AFC.

"except of course the AFC tuners that use that knock sensor reading." I never said to tune to the point of knock it is just there for notification so when you tune to the AFR you are trying to hit.

"Dynoflash dude said, find a better solution. The AFC is not good enough for my $30k car" It was probaby the same price as you datalogger, and it can't do anything for you but let you know.


Bottom line this point can be argued until we are both blue in the face so please just take it for whats it worth and to you that is nothing but it can be a useful tool in others eyes for very mild tuning. It is better than nothing at all, that is why it is on the SAFC.

 

Don't trust it, don't use it.