Problem: Engine knocking at high RPM

[g4i8y0t]

Hi all,

My engine (D16Y7 non-VTEC) is knocking at above 5500-6000 rpm. Is it caused by not enough fuel sprayed into the combustion chamber or something else? Sifus pls help...

 

[mADmAN]

most likely lack of fuel....best way to know is to put it on the dyno and get the a/f reading

could also be due to an advanced ignition.

 

[g4i8y0t]

I see... I'll retard the ignition first and see if that helps. Thanks mADmAN.

 

[xtremeleo]

fuel quality maybe, any of my rides will ping with shell fuel, other fuel they'll behave like normal jer

 

[g4i8y0t]

fuel quality maybe, any of my rides will ping with shell fuel, other fuel they'll behave like normal jer

Really? I'm using Shell fuel. Will try BHP or Petronas after this. No more bonuslink points...

 

[xtremeleo]

i suggest esso highly, petronas is also good but using it halves the mileage compared to when i use esso

 

[g4i8y0t]

i suggest esso highly, petronas is also good but using it halves the mileage compared to when i use esso

So, does that mean if you can get 500km when using a full tank of esso RON95, you'll only get 250km when using petronas RON95?

 

[xtremeleo]

yes, sumthing like dat.. on long distance, its not halved but doesnt cover as much mileage with petronas, dats all. its still a good fuel brand imo

 

[g4i8y0t]

xtremeleo, I wanna ask something. You said earlier that your car pings when using Shell fuel, but does not if you're using other brands. Is the ping loud or very noticeable or just barely can hear it?

 

[xtremeleo]

its not dat loud, but noticeable. the thing with pinging, its already too much when u can hear it

 

[sexycar]

to me, shell is the worst petrol for vtec. I think they add water inside the petrol. Pinging on high rpm is the most unwanted type
of ping... it is very dangerous cos your engine is at high load & high speed... better get it fixed

 

[aalto]

It reversed for me, I use shell 95 & its the better in terms power & FC for my stock B16A engine...(compared to Petronas)

 

[xtremeleo]

aalto, maybe its the driving style.. i dunno for sure, but dats one of the variable to consider imo

 

[6UE5t]

yes, sumthing like dat.. on long distance, its not halved but doesnt cover as much mileage with petronas, dats all. its still a good fuel brand imo

I've tried Esso, Petronas, Shell, & Caltex. Actually I do not notice much difference between them in terms of fuel economy. Now keep using Esso just because I got the point card. :)

 

[g4i8y0t]

Update: I retarded the ignition timing a bit, the knocking sound is still there. I've changed the spark plug and plug cable, but it's still the same. Could it be caused by clogged fuel filter? I changed the filter about 2 years ago.

 

[6UE5t]

Most probably due to already a lot of carbon deposits inside the combustion chamber. The sharp peaks of the carbon deposits easily heats up hence may cause abnormal ignition of fuel and causes detonation/knocking. The carbon deposits also slightly increase compression due to making the combustion chamber volume a bit smaller, hence also increase the risk of knocking. So you may need to retard the timing even further.
A lean fuel mixture also increase tendency to detonation, so you may also need to check your air/fuel ratio or lambda reading and make it slightly richer to combat detonation.

Of course, doing those would likely result in less responsive performance and higher fuel consumption. You may also try some carbon cleaning before doing any adjustments to at least reduce the carbon deposits a little and improve a bit. But if the deposits are already to much then it wont help much as well and you need to do a top haul to clean it 100%.

Btw CMIIW since I'm no mechanic. :)

 

[mADmAN]

like i mentioned before... go put the car on the dyno and check ur a/f

from there...u can start checking ur problem....u may even get the person doing the dyno to help set ur distributor if it helps with the pinging.