Knock Sensor Question

[justjuiceit]

How much timing can the computer take out when it detects knock?

[WDRacing]

IIRC it takes out 4 degree's.

[MikeMurphy]

is it progressive? or just on and off?

[justjuiceit]

Also, what kind of voltage does the knock sensor have to put out, before the timing gets retarded? The owner before me put on a very loud exhaust, so its really hard to hear any knock. I was thinking of hooking up a little LED light to let me know, has anybody done this before?

[klattr1]

i constantly have a knock sensor code even though my air fuel ratios are good and my base timing is correct. I unplugged my knock sensor harness and my car runs the exact same. So should I just advance the timing 4 degrees to offset it?That would be a band-aid on the problem until I replace the sensor or the wiring but I can guarantee you from past experience and from what my friends say; as soon as i replace the sensor, the code will come right back.

[justjuiceit]

Alright, I hate to ask, but what does IIRC stand for?

[WDRacing]

If I Remember Correctly...no problem man. If your getting detonation loud enough to hear, your in rough shape. Buy a knock meter, I use the MSD knock meter, works like a champ. I'm not exactly sure how the ECU goes about retarding timing with knock, so I wouldn't use what I say as the example to go buy. There are alot of things that can induce detonation aside from lean A/F's. A bad thermostat can even give you troubles.

For a DIY knock meter, I have read somewhere on the net how to build your own. It was fairly simple.

WD

[klattr1]

well, i am not hearing any signs of detonation for sure. I've heard it once and it was too late to save my motor. I dont have a thermostat in but Im thinking its a bad knock sensor or the wiring is faulty based on two things:1) the code comes back after 10 min of driving under 4000 rpm and no boost whatsoever.2) my car feels the exact same in WOT even with the knock sensor harness unplugged.I havent had any time to get a voltmeter and test for continuity.If I find anything out, I"ll let you know.

[WDRacing]

My Skyline used to throw that code at me. But I had my sensor unplugged. If the sensor is unplugged the ecu should be retarding any timing. Its a weak safety measure at best anyway. Just be sure to keep the A/F's rich and keep the engine cool.

WD

[C-Kwik]

I've been getting a knock sensor code. I doubt it comes up when it detects knock. It never did before when I did get some detonation. And I don't get any detonation now. I'd say it's a bad sensor or wiring. In fact mine started throwing the code only after fixing the wiring problem for my coolant temp sensor. So I suspect either there might have been an issue with the KS wiring that I might have caused to fail completely when I was repairing the harness, or coincidentally the KS may have gone bad. It runs fine now and I haven't had time to tend to it or test it so I'm not in a big hurry at this point.