Power Fc Knock Sensor

[muzziak]

So my knock sensor was going crazy the past week or two, hitting values as high as 140-150 but sometimes staying low, never anything really consistent. I took it back to the tuner and on the way the AC pump started to make heaaappss of noise. We bumped down the timing a bit to reduce knock, but the tuner was saying the AC pump being on its way could also contribute to the large knock. Any validity with this statement ?

Thanks

[GTSBoy]

Yup. It's not the "Power FC knock sensor"....it's the OEM knock sensor, and they are famously able to pick up other engine noise. Anything that involves bits of metal hitting other bits of metal can end up sounding like pinging to the knock sensor. The OEM ECU does a better job of filtering the audio from the knock sensor. The Power FC software is a bit more shit.

[muzziak]

Ah sorry my mistake, well that's good I guess. After tuning the timing down the high readings did mostly stop so could be a combination of both I presume ? Best change the pump then. Thanks heaps

[89CAL]

Did you turn the AC compressor off or even pull the belt off to eliminate it as the problem?

[Ben C34]

I really hope he pulled the belt off to confirm.

[muzziak]

No the belt wasn't pulled off. When the AC was played with (on, off) the noise would change, going really loud when it was on. Should I pull it off ?

[89CAL]

I would to see if the knock stays the same etc.

While turning it on and off should elimiate the major rotating parts, it may have a faulty clutch or noisey bearing etc. I would pull the belt off just to see

[muzziak]

I'll take the belt off tomorrow and check. The timing was turned down this morning, and after a whole day of driving the highest I got was 50, other than that it was about 10, and only once so I guess that did help.

[muzziak]

They also used some weird stethoscope looking thing which led them to say noisy bearing. Is driving without the AC belt harmful in anyway ? I have a track day coming up and just want to make sure

[Ben C34]

How would not having an ac belt harm anything?

How much less power did it make with less timing?

[89CAL]

A/C belt only drives the A/C so will cause no harm at all.

The fan belt drives the altenator as well as the water pump so it shouldnt really be removed for testing as you will have no water flow through the engine

Power steering and A/C Belts only drive the one thing so can be removed for testing

[muzziak]

I didn't know, that's why I was asking Ben. We didn't put it on the dyno, just plugged the laptop in. He said it was down a bit, not enough to feel any difference though so I imagine a few kW ? Awesome, I'll take off the belt then and drive like that on the track day