High Knock Reading

[Hulk1010]

does a powerfc and knock readings of 70+ every now and again mean the car was not tuned properly?

[R31Nismoid]

yep

[Hulk1010]

so what should i do, i'v taken the car back numerous times and it's always the same result, all that happens when i take it back is the tuner just keeps lowering the timing, to me it seems like he just can't be bothered

I might as well get the stock ecu put back in, cause thats what it feels like

Edited April 21, 2006 by Hulk1010

[R31Nismoid]

He isnt lowering it in the correct point obviously.

Either that or he is a shit tuner.

Tell him you are not happy.

Is it always on full song or anywhere particular?

[BHDave]

It really depends where it is knocking.

If it's on over run then not a major concern, or if you are bouncing off the limiter then it isn't uncommon as the pfc cuts fuel creating a lean condition

[rob82]

It really depends where it is knocking.

If it's on over run then not a major concern, or if you are bouncing off the limiter then it isn't uncommon as the pfc cuts fuel creating a lean condition

Fuel cuts aren't a lean condition as all the injectors are shut off. Knocking on the rev limiter is usually from crackshaft harmonics due to the massive rotational decelleration. Find out when the knock occurs and we might be able to help you out more.

Edited April 22, 2006 by rob82

[Hulk1010]

thanks for the replys

I'ts always before the limiter, at random times, I might give it a boot from 2nd, 3rd, 4th etc and end up getting a high reading, could it be the knock sensor?

a week back i gave it a boot from second and then checked the knock level reading and it read 111, the RPM was 5500

[R31Nismoid]

111 @ 5500rpm would suggest to me that its either a faulty knock sensor.

Or poor tuning.

I know which i'd be pointing the finger at aswell...

[rob82]

thanks for the replys

I'ts always before the limiter, at random times, I might give it a boot from 2nd, 3rd, 4th etc and end up getting a high reading, could it be the knock sensor?

a week back i gave it a boot from second and then checked the knock level reading and it read 111, the RPM was 5500

By that knock level you should actually start to hear it through the fire wall. Is it a temperature based problem ie does it do it at night on the highway or slow cruising around town in the heat of the day?? If you pull 2 deg out globally does it stll do it??

[itbmils]

By that knock level you should actually start to hear it through the fire wall. Is it a temperature based problem ie does it do it at night on the highway or slow cruising around town in the heat of the day?? If you pull 2 deg out globally does it stll do it??

OK - I kind of have this problem too – but not as bad

I have an R32 GTR with Weisco forged pistons - and my knock reading creeps up to the high 50s from time to time. I have also seen bursts up into the 70s but only if I'm using bad fuel.

I have had my engine checked by 3 different tuners - all using head phones to listen for knock - and they all confirm that my engine is NOT knocking

Under the settings menu on your PFC you add advance / retard timing and increase the injector duty cycle across the entire rev range – or 'globally'

I tried taking timing out in steps. I stepped up from -2 / -4 / -8 degrees - and it made no difference to the readings.

I then added more fuel 'globally' - still no difference

I then did some tweaking to both at the same time – still got the same readings (shrugs)

So - I figure I either have a dodgy knock sensor - or just a noisy engine

or possibly both

[paulr33]

a quick run around on the street with a friend watching the hand controller would take no more than 5 minutes to sort out. where are you located

[N I B]

The knock reading can be misleading as ive seen many cars with high readings with no det at all.One GTS read a count of 93 no matter what you did, we even backed the CAS off asd far as it could go and retarded timing with the PFC with no change,even changing the knock sensors did nothing.Use the reading as a guide only but its no where near perfect so us other means as a back up if your not sure.

A maximum power tune will give readings in the 50s also,this is why i like to use other tools for det detection on the dyno on hi powered cars.

[MattSR]

Like the chassisear?

[Dash]

Does it do it all the the time?

Every now and then I'll get really high readings,spoke to the tuner and he mentioned it could be the fuel pump.

I've just replaced it and its still playing funny buggers, highest knock of 120 when overtaking in fifth gear with less than 3 qtr throttle.

All other times sits on mid to low 30's!

[Topaz]

same boat **raises hand.

Mine has hit a max of 84, but after a bit of driving in low and high revs the knocking is down to lower than ~30. Is this a problem at all?. If I am driving with no hard boosting the knocking is lower than 20....

Also have been told to watch for blowing smoke.

White = water

Brownish = fuel

Black = oil

is that right?

[Hulk1010]

should i get my mechanic to check out my knock sensor before i do anything else? the car is due for a service soon anyway so i could get him to do it then

[benm]

I've put about 6,000km on my GTR in the past 4mths driving in conditions from 5c-44c on 0.8-1.4bar and never have I seen my knock level go above 32.

Maybe it is time for you to find a different tuner Hulk.

[Damo]

I have the same problem with my gtstr33. it spikes upwards of 120 with the aircon on, and up around 50-60 with aircon off. It happens at around 4500-5000 rpm.

I have my map locked so i cant take out any timing to do some fault finding. This is quite annoying seeing the engine check light flash rapidly at me. I hate the thought of slowly killing my engine.

I had mine tuned at one of the best tuners in sydney and it was not detonating on the dyno. I even took it back for them to play with and they did take some timing out. I am wondering if its possible for the car to be using different load points under wot on the dyno to wot on the road. In this case that part of the map may not be tuned????

Does any one else notice a rise in knock if the aircon is on???

[paulr33]

take it back and ask for the tune to be unlocked so you can correct their mistakes. simple. or make them fix it for free.

[Mr Italy!]

^ The engine is working harder with the aircon on... so its gonna show up.

Take it back to this "one of the best tuners" and tell them its still happening. Sacrafice a little bit of power for the overall health of your engine...