Knock light whilst stationary in neutral!?

[lockwood77]

Hi all, whilst out (unsuccessfully) testing my water injection setup yesterday, I sat in neutral and booted the car, only to prove to myself that you don\'t get boost in neutral...

Anyway, the knock light (heat lamp) flashed away and I looked at the Commander to see a high of 91!

I also got the light flashing as I booted up a sliproad in third, but it flashed when I feathered the throttle, not at WOT. I have noticed this very occassionally on track too, particularly at a very wet Donington through the Craner Curves when some gentleness with the right foot was required!

Am I right in thinking that this is likely to be exhaust noise (either movement or fuel popping) setting the knock sensor off? Before that, the highest I saw was 60 and that was with a full first/second/third gear WOT down a dual carriageway. No light flashing.

[BlitzBoy]

most probably your exhaust popping and stiff suspension causing the knock light to come on, the knock sensor is a microphone at the end of the day

[lockwood77]

What I thought, just a bit concerned when you see a red light flashing on the dash!

Presumably if it was "real" knock, it\'d be happening at WOT/full boost?

[BlitzBoy]

yes if you get it at WOT at the top of 3rd or 4th then I would say thats real knock

[Nik da Greek]

Mine does this in a random stylee (or it does on the rare occaisions the car actually runs).  It seems to be an intermittent fault with the knock sensor, because obviously it wouldn\'t put up with 90+ knock levels without blowing itself to bits!

[nikp]

Mine gets high knock the first one or two times I boost it, which is usally light throttle opening and just a little boost. Quite consistent, and boosts fine afterwards.

[Kim]

I had this too on a customers car, it really bothered me.
Now that I think about it, I dedn\'t seal the threads on the knock sensor when I installed it.