Engine Knocking

[dynafit]

Hey SAU,

I am having trouble with engine knocking. I have tried a 500ml bottle of Wynns Octane Booster, which claims to stop engine knocking, and there are still knocks. I put the booster in before i filled the car up, drove around slowly for a few mins to help mix it through the tank (like going around roundabouts, swerving side to side down the road *like the racecars do when they warm their tryes*) and still get the knocks.

When i start the engine, there are 1 or 2. whenever i try put my foot down, the number shoots up to about 30-40.

I have to drive 4 hours home tomorrow so i am hoping to get some help by then.

Things worth noting:

I have recently had the battery disconnected, and a larger battery put in.

Before i put the octane booster, after i put the foot down i had 58 knocks. So, the booster helped a little but there are still problems.

I have the following mods- Apexi power fc, apexi boost controller, 3inch turbo back exhaust.

Only run 98 shell V power

The car is on stock boost.

Cheers,

Lachlan

[DVS JEZ]

Go in to settings then inj/ign trim and trim the ignition down 5 degrees until u get a retune.

U will need to do this everytime u start the car as its only temporary.

This should be enough but keep an eye on the knock still

[boostn0199]

Speak to whoever tuned your car and get them to have a look at it will probably just need to touch it up abit. If you havent tuned your car and are complaining about knock form just sticking the pre tuned power fc well theres your problem.

[R31Nismoid]

30 is perfectly normal for most tunes and within acceptable range.

The motor will never have zero, in fact you will rarely see the sensor read below 10.

If you are worried about the tune, it's quite simple - Don't drive around on boost.

If you stay off boost, low load/RPM then it should be fine.

[dynafit]

Speak to whoever tuned your car and get them to have a look at it will probably just need to touch it up abit. If you havent tuned your car and are complaining about knock form just sticking the pre tuned power fc well theres your problem.

i bought the car tuned, and since the battery came out im guessing it reset itself. Spose i can contact the seller, but regardless i will need a retune it seems.

[boostn0199]

i bought the car tuned, and since the battery came out im guessing it reset itself. Spose i can contact the seller, but regardless i will need a retune it seems.

The powerfc doesnt reset it self no matter if you disconnect the battery. Either your using different petrol or maybe even the hotter weather conditions have effected it. But yeah Id say best thing would be take it to the tuner and hell quickly chuck it on the dyno and fix it up.

[dynafit]

Go in to settings then inj/ign trim and trim the ignition down 5 degrees until u get a retune.

U will need to do this everytime u start the car as its only temporary.

This should be enough but keep an eye on the knock still

I just got back from a run, where i set the timing back 5 degrees. It worked, i got a maximum of 9 knocks, with 4 coming from starting the engine (before i could change it). got 5 knocks one way, and then 0 on the return trip.

Is there a way to permanently set it back 5 degrees instead of everytime i start the car? like make it the default setting or something.

[paulr33]

read the PFC FAQ on correcting knocking in my signature

you cant set the temp ign adjust as it clears each time you key off and isn't meant as a permenant fix

ie; you would not want to -5 the whole map, it would suck

you only need -5 deg where its knocking and -2 might even be enough

you need to speak to a tuner and say your car currently knocks as is, but if you -5 deg its fine

and they should adjust the "max load" are on the map and take out some timing

dont let them adjust the "CAS" or back dial it. some lazy tuners do this

dont let them shift the whole map -5 or -2. some lazy tuners do this

you only want the max load area -2 (or whatever the magic number is)

[89CAL]

Those Knock levels seem super low.

Perhaps you should try a different fuel besides V Power?

Just saying, it might be as simple as changing to BP Ultimate or one of the other 98RON fuels

[JonnoHR31]

even 58 isnt all that bad, needs fixing tho. 1 degree from the suspect cell should fix your troubles. as paul said, read his faq, has everything you need to know. could also find someone in your area with datalogit if you dont want to pay for dyno time

btw dont keep using octane booster, once off is ok but it destroys plugs and o2 sensors really fast with continued use

[paulr33]

and it costs you extra money each time and it wont fix the problem, retune the few cells that are knocking and your done

[STATUS]

try bp or mobil, before panicking. The shell near us seems to have similar results.

[dynafit]

and it costs you extra money each time and it wont fix the problem, retune the few cells that are knocking and your done

Ok. I read your guide, and i have done for a while now its great fixed my airbag light blinking also which was a bonus!

But, while trying to understand the map tracer and changing the ignition timing manually, i have not figured out how to see which cells need to be changed. How can you tell what cell or cells are knocking? and how can you tell what to change them to?

[dynafit]

I will also try changing the fuel to BP ultimate when i next fill up, but i hope that wont be the issue. It would be a right pain in the arse if i had to only fill up at BP.

[89CAL]

Bit cheaper then a re-tune but lol?

The map tracer makes it really hard to see where the knock is because it only shows you what cell you are on not what figures you are getting on that cell..... The only way to really do it as far as I know is to find the point where it has a high knock (eg full throttle, 3rd gear, 5000rpm) and then mimic that in map tracer to find the cell where it is getting this bad knock

This is a pain really... Much easier with FC Edit or another program seen as you can log in Map watch what cells are getting which figures.

Im happy to be corrected if wrong but I think eleminating knock on the hand controller is pretty time consuming

[The Dan]

Take it to a tuner and get it tuned.

Just because you have the number 30 there or 50 even, doesn't mean it knocked 50 times. That is a value to tell you the intensity of knock. 50 being higher than 30 for example. 30-40 is acceptable. 50 is getting high. If you take it to someone who knows what they are doing, you may get away with fixing it instead of melting a piston because you changed something you shouldn't

[R31Nismoid]

Those Knock levels seem super low.

Exactly. There is no way the PFC was registering "0" knock.

[dynafit]

Exactly. There is no way the PFC was registering "0" knock.

One way up the road, i got up to 9 on the knock meter. then, when i turned around and came back, it didnt change from 9. Thats why i said it had 0 knock.

Before "elite racing" mentioned that the number displayed is actually the level of knock, not the amount of knocks, i never actually knew that. So, its possible that it knocked along the way home and didnt go above 9. I should have switched the motor off after one way, to then see what happened on the way back, but i never knew how the knock counter worked.

I will do more testing tomorrow and see some results, as i will need to refil after the trip home so i will use BP to see if that works to check that possibility. I have booked a tune in for monday afternoon so if it isnt a petrol issue than i will see what the tuner can do.

Thanks guys

[JonnoHR31]

the number value is the max you've reached, you can reset the max by pressing the right arrow. ignore anything under 30 as its just noise not actual knock, or if it is its nothing to worry about.

[DVS JEZ]

Bring it over monday night and ill hook up the wideband and datalogit and we'll get it sorted in no time.