So we were out for a drive a few days ago in the rx7 and the apexi power fc hand controller started to show some knock, it would just randomly spike up to about halfway. It has never done this before and it used to only show a tiny bit. Now it still shows more knock than it used to. What could be causing this? Is there anything I can check easily? Any suggestions are appreciated.

thanks

 

I'm not a tuner but I think some indicated knock is normal while just driving/cruising and you're not in boost. It's likely just picking up some other vibration or resonance from the drivetrain and that level is a bit different from car to car. But as I understand it, knock should not rise, or even go down once you're into boost. If it rises then I'd first check the sensor screen and make sure the knock sensor isn't shaded. If it is I'd check continuity or get a new sensor. Then I'd make sure that my gas is AT LEAST 91 or higher (not sure how it's rated in Scotland but the higher the better). If those aren't an issue I'd stay out of boost until I got it resolved.

 

Thanks for the reply. There used to be a little bit of knock and I thought that was normal aswell but I noticed it because it suddenly started to go so much higher than it used to. I am still new to the power fc so am not sure how to get onto the sensor screen. We use e97 so I don't really think that is causing it.

Thanks again, Ethan

 

If it happens at low rpm or cruise areas during noisy events (throttle blipping, coming on throttle hard, thermofans coming on, shifting gears, hitting a bump, gear shift, etc) then it's most likely just other noises being picked up by the knock sensor. It just filters for anything around 3500Hz, which could be caused by a range of items under the hood.

Real knock would be a lot more likely to appear at high rpm, high load conditions (and I've found this is where those transient noisy events are less likely to occur). So if you're seeing it only during those low load areas I wouldn't be worried.

 

I still haven't got this fixed yet and was wondering if you could help me again. I changed the fuel to better quality stuff and it didn't make any difference. The knock seems to go down when the second turbo kicks in and was thinking it must be an issue with the first turbo overbosting, mabey wastegate or something?? This has still got me confused so I hope you can help me

thanks, Ethan

 

Again, some knock is normal. Exactly what is the value? Maybe a tuner will chime in, or when you have enough posts you can ask in the 3rd Gen. Tech section.
You know another thing that will reduce knock is WI. You can search for threads under my name in the Auxillary Injection section for a low-cost but reliable water injection system that's also very stealth and provides additional cooling and carbon control at the same time.

 

Some knock is very normal, excessive knock dangerous. Without knowing what levels your hitting or if using a pfc commander as a reference how far on the bar graph your reaching we can't really advise.

 

What should I do then. Should I take it to a tuner and see if the map is out.

 

That's what I would do. Did you get it sorted out?

 

^ He never would post his knock values...despite multiple requests.

 

I am not sure how to find a value for the knock all I can see is the graph. If you help guide me then I will post a value.

 

Should be available like it is on my Commander unless someone has changed the display....

---> http://www.paulr33.com/powerfc-faq/f...nstruction.pdf

 

Alright guys sorry for the late reply, I changed the spark plugs and patched up a boost leak before taking it for a run. The graph showed exactly the same as before but the highest number that came up was 50. That doesn't seem much higher than what I've read does it? Is that a normal number to see
Thanks,
Ethan

 

After I had my car professionally tuned, the car still showed 40-50 on the knock graph when driving normally at low engine loads, even though the car ran perfect (ideal AFRS in all conditions etc )


Your knock reading of 50 is most likely normal because the PFC picks up other noise as well.

Here is a thread that should also help you
https://www.rx7club.com/power-fc-for...cation-427250/

 

awsome! Thank you very much. I was worried over nothing then, but at least I know it's safe now.

 

If you have a datalogit for your power fc, you should join the community for power fc.