Knock Level Increase...hmmm

[Marko R1]

hi guys,

i did a search & couldnt find what i was looking for - as of yesterday my knock has increased as i noticed this in 3rd gear when i got to 6500rpm @ 24psi, read 70+.

when i reduce the boost level to approx 20psi the knock drops to 40 (as per pfc) & even lower boost showed 25knock.

my tuner will check this out for me but in the meantime i would like to do a check over so i dont waste his time...paul (mr swiper) was suggested i blow out the loom connectors with an air compressor as water may have entered the connectors when i washed the engine bay last week & also to check that the spark plugs all look the same (maybe a plug has failed?)

is there anything else i should check OR has anyone else experienced high knock due to something rattling/loose in the engine bay? i dont want to feel like a d1ck with my tuner if something else is causing this bizarre reading...

thanks.

marko

[Scradly]

Possible that you have picked up a bad batch of fuel. If nothing else has changed its weird that it will suddenly change.

I would have it looked at asap.

[R31Nismoid]

It'll probably just be a cell that is slightly in need of attention.

Nothing major

[Marko R1]

  Scradly said:

Possible that you have picked up a bad batch of fuel. If nothing else has changed its weird that it will suddenly change.

I would have it looked at asap.

this is what i 1st thought - i ran the car basically dry then refilled at another bp servo (98 ultimate) & same thing.

[Marko R1]

  R31Nismoid said:

It'll probably just be a cell that is slightly in need of attention.

Nothing major

yeah i had a squize at your pfc faq...you are probably right.

i have dropped the boost level anyway, better to be safe than sorry

[Nee-san]

  R31Nismoid said:

It'll probably just be a cell that is slightly in need of attention.

Nothing major

+1

Yes indeedy, i had a knock reading of 120 randomly one day doing about 200kph, this was after consistantly never reading over 20 so probs like R31Nismoid said just a cell need a little love

Cheers,

Mitch.

[Pattygtst]

or coils if the tune is good

[Marko R1]

  Pattygtst said:

or coils if the tune is good

If it were coils I would probably feel the loss in power in higher revs? Although this also crossed my mind

Would a faulty coil cause this symptom, I don't think so as the symptom would be hesitation

I will pull out the plugs tonight and if they look the same then off I go to my tuner

[Pattygtst]

there wouldnt be any loss of power i would think it may just have a little unoticable missfire that would show up as knock. Happened to me.

But to be honest it sounds like your tune as your knock levels went down when you put loss power down.

[NickR33]

tuned in summer? temps dropped up there recently? cold night maybe... other than that its probably as Ash suggested if you have already ruled out fuel

[Marko R1]

  NickR33 said:

tuned in summer? temps dropped up there recently? cold night maybe... other than that its probably as Ash suggested if you have already ruled out fuel

It was tuned on a 33deg day, the problem appeared on a 18deg day...could a drop in temp cause it?

[R31Nismoid]

Yes, most certainly.

As everyone has said, more than likely just a cell or two that need minor attention.

I think you need to buy a stress ball or something, a minor one-off knock is hardly anything to get excited about.

Take it back to the tuner, get it fixed. Should take less than 30mins. Drive it sensibly until then... easy as pie!

[Dose Pipe Sutututu]

even dirty injectors/bad fuel reg could do it, plug in a wideband O2 and see how it's reading

[Marko R1]

  Pattygtst said:

or coils if the tune is good

u might be right here - ji ust pulled out the plugs & no.4 plug is a lot blacker than the others...when i look at the coil pack for this plug it seems that the black lead tip on it is shorter than the others

[Marko R1]

paul - you are a legend mate, i think once again u are right - you freak!

i spoke jim @ crd & he explained that the coil pack was mis-firing with the pitted coil pack lead tip which is why the plug was black & this causes all sorts of things i.e. spark over which makes noise, even possible pinging.

i haven't test driven it yet but i'd say it is fixed im almost ready to put my head on the chopping block if its not rectified

i will report here once ive take it for a wrap on a long straight, 3rd gear under load

worse case i may need to buy a set of splitfire coilpacks

[Swiper the Fox]

  Marko R1 said:

paul - you are a legend mate, i think once again u are right - you freak!

i spoke jim @ crd & he explained that the coil pack was mis-firing with the pitted coil pack lead tip which is why the plug was black & this causes all sorts of things i.e. spark over which makes noise, even possible pinging.

i haven't test driven it yet but i'd say it is fixed im almost ready to put my head on the chopping block if its not rectified

i will report here once ive take it for a wrap on a long straight, 3rd gear under load

worse case i may need to buy a set of splitfire coilpacks

[Marko R1]

hi guys,

last night i took my car for a drive with new my splitfire coil packs & it is still knocking high so ive left a msg for my tuner to look at my car. i was hoping the coil packs would have solved it but anyway...the joy of modded cars!

2nd gear showed 34 peak knock, 3rd gear showed 66 peak knock.

i then cruised below 3krpm in 4th gear @ 60kmh - when i reset the peak knock on my pfc hand controller it immediately shows above 20 peak knock & as high as 25 peak knock (i did this back2back test a no. of times & got the same result every time). HOW is this possible on such low revs??? i think my knock sensors are not reading correctly, either they may might need replacing as ive been told they can fail OR maybe 1 of them has become lose over time, i luv playing the guessing game (reminds me of an ex-girlfriend)

if the problem was just a cell that needs attention as suggested in my above posts, would i still have the same results considering the circumstances i.e. low revs, high knock?

[R31Nismoid]

20 on the knock is no issue. Just driving around mine i think sits around 10-20.

There is always going to be some noise picked up, the fuel is combusting after all.

You only really need to worry about knock when it gets over 30-35. Anything below that is largely irrelevant.

[krzysiu]

I think i got a bad batch of BP 2 days ago. Car pinging like shit. Hit 92

[Marko R1]

I've been using bp ultimate for the 5+yrs due to public perception, is it still the case to be the highest ron and cleanest fuel out there? Maybe I need to switch?