Problem: SAFC-II Registering Knock

[PooJou]

Hey guys,
My engine fan carked it a few days ago, and i went to change it today. Now the thing is, the SAFC-II readout is showing knock still, even after the fan was replaced. This knock is not audible (the only reason i knew is because the display said so) - and it ranges from 3 to 20. What could the problem be?
Thanks in advance!

[chris davey]

I didn’t know that SAFC II’s could register knock. How is it hooked up? How many knock sensors does your engine have? What is the max amount of knock the safc goes up to? What sort of fuel did you have in it at the time? Were you labouring the engine at all? Anything else changed since before when it wasn’t registering any knock? If the safc has the same sort of scale as a Power FC I probably wouldn’t be too worried about it as from what I know people usually tune to keep the knock under 30 or so. You could try putting some octane booster in and see if there is any difference. Also, remember that knock sensors can detect other noises that aren’t actually knocking so check for anything that may be giving it a false reading.

[PooJou]

I didn’t know that SAFC II’s could register knock. - Well it's registering it atm.

How is it hooked up? How many knock sensors does your engine have?

- Not exactly sure, it's a MAP sensor'd AE92 4AGZE
What is the max amount of knock the safc goes up to?

That is another unknown, if it went up to like 300, i wouldnt care :/

What sort of fuel did you have in it at the time?

I have a feeling i got a bad batch of Synergy8000 from the mobil nearby. I have been filling it there for the last 2 tanks.

Were you labouring the engine at all?

Nope, idling and it's registering 3 or so... it didn't do that before

Anything else changed since before when it wasn’t registering any knock?
Nope, aside from the busted fan.

I'll fill in at my own petrol station and see if it goes away

[1200det]

The SAFCII does not have its own knock sensor its taps into the OEM Knock sensor.

Your standard ECU reads a few inputs including the knock sensor to determine if pre-igntion or detonation are occurring. The SAFCII does not have this built in logic so it only reads what the OEM sensor is telling it. Remember the OEM knock sensor is so sensitive it picks up every little engine sound.


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[PooJou]

So i shouldn't worry about this minute bit of knock? As i said i'll fill in at my own petrol station because i have a feeling now it's a bad batch of fuel :/

[SilverGhost]

I had the same worries when I had mine installed. Apparently the reading goes as high as 200, and anything up to 50 isnt really worth worrying about.

On hotter days the readings can hover slightly higher than normal, but at night or on cold days it rarely went above 5 on my car (2nd Gen 3SGTE).

What you need to watch for are sudden spikes which indicate a strong knock signal was sent to the ECU, if you are getting a lot of spikes above 80 or so when under load then that could be a sign of pinging.

[sleek3]

on my 7M-GTE with the S-AFCII i dont know since it is not tuned my knock is always reading 0 why is that

[SilverGhost]

Sleek3 - Im not too familiar with the 7M, so i dont know if its knock sensor equipped, if it is , then it could be that the knock wire from the SAFC isnt wired in to the knock wire on your engine loom, If it isnt, then there is no reading to receive.

[whatthe?]

The 7MGTE has 2 knock sensors and my SAFC II displays up to 20 knock on occasion. You also have to set knock values whilst free revving at 1500 and 3500 rpm from memory. Have a look through the settings part of the menu.

[takai]

The knock sensor on that engine always used to register between 2 and 5, sometimes up to 7. The interesting one was when i had the cars shocks tested at the Pedders. Just the vibration from outside the car was enough to have the knock sensor registering 2 or 3.