Detecting engine knock

[Rein]

Sifoos sifoos sekalian....

we all know knocking is the driver's worst fear and engine's worst nightmare.
But how do u know that the engines is knocking??

Too often, we onli look at the AFR.... need you guy's opinions :)

 

[PutraCraze]

buy hks knock monitor.... or j's 2 in 1 knock/afr monitor....

 

[alvin24]

You can actually hear it... slight knocking is fine (carbie cars always knock!)... accessive knocking and kiss ur engine bye bye... =)

However... a stoichometric air:fuel ratio shouldn't create any knocking.

WAnna hear how engine knocking sounds like? Drive a carbie car... when climbing hill that time, shift to 3rd gear and floor it... car won't have enuff power to climb the hill... and you can feel a metallic knocking sound coming from your engine. Thats engine knocking.

Correct me if i'm wrong... =) :P :P :P

 

[MrNismo]

Knocking is indirectly related to A/F ratio, although lean A/F ratio will contribute to knocking.

Yes you can hear hard knocking but not mild ones, especially on tuning cars with loud exhaust and such. If the knock really comes as hard until you can hear it clearly even though you have a loud exhaust, all it takes is a few seconds to send the engine to hell.

Knocking can be detected via knock sensors, which are piezzo sensors usually that detects vibration. The HKS A/F Knock Amp and similar devices are just monitors that interacts with the user. Some tuners and dyno operators will use a stethoscope to listen to knock when tuning the car.

 

[polyxtroy]

HOw bout this. SAFC2 has got a knock sensor input. If I were to fully utilise this, can I put in an aftermarket sensor? What sensors plugs straight in to SAFC2? My ECU does not support knockings.

 

[delphinium]

quite an info here and I'm afraid I'm gonna be the next victim :( .. ok, so much of how to detect engine knocking. Just how on earth now do we :

i) avoid / prevent
ii) cure in a case where the engine is already knocking? .. (touch wood)

does retarding the timing help? thanks all.

 

[SiGNAL]

Retarding the ignition timing and/or increase the fuel input(bigger injectors, bigger fuel pump, fuel regulator) will help prevent/cure engine knocking especially turbo cars.

 

[Rein]

hmmm...thanks for the feedback....

I understand that engine knock emits a certain sound frequency which aftermarket monitors (HKS knock monitor) utilizes on..

however, not being financially capable of owning such equipment, we normally resolve to our own ears....but how exactly does knocking sound like... i've surfed many sites and read many articles....some say its a high frequency ting....some say it like a hammer tap on the engine and some marbles in a tin can....

how are u assured that knocking is not happening / make sure it doesn't?

 

[eterna2772]

try thiss.... maybe it will help...


http://www.ecanfix.com/~mdhamilton/fuelmod.html

 

[polyxtroy]

When it's knocking, you should be able to to hear Ping-ping sound

 

[MrNismo]

Try doing a reading on these links.

http://zhome.com/ZCMnL/PICS/detonation/detonation.html
http://www.misterfixit.com/deton.htm

 

[MrNismo]

Originally posted by polyxtroy@Oct 27 2004, 22:28
HOw bout this. SAFC2 has got a knock sensor input. If I were to fully utilise this, can I put in an aftermarket sensor? What sensors plugs straight in to SAFC2? My ECU does not support knockings.

The SAFC2 is suppose to work with the factory knock sensors I think. You can do a search on aftermarket knock sensors, but I have no idea whether they can be calibrated to work with the SAFC2.

 

[Rein]

thanks mr.nismo...
info was very helpful...

 

[calvintys]

Here http://www.msdignition.com/tool_8.htm ... good luck

 

[stroker_kit]

r u guys sure that knocking sound can be heard by human ears??? i tot u'll need a special sensor to monitor it..

thankfully like my case, my engine oredi got stock knocking sensors...

 

[e819]

my engine also knocks.. but above 2500rpm, 2 avoid the knock i hav 2 retard till 4degrees, i installed AFPR, currently the distributor had 2 be advance and fuel set to 61psi, so frustriated >> above 2.5krpm can hear the knocking sound, btw it has run 4 quite sumtime like dat.. any solutions sifuss??

im running on 4G92 SOHC converted to twin cam (4G91 head)

 

[V8_nutter]

r u guys sure that knocking sound can be heard by human ears??? i tot u'll need a special sensor to monitor it..

thankfully like my case, my engine oredi got stock knocking sensors...

Yes,,knocking sound can be heard. The sound is like szrrratt or qroooozz and some like electricity buzzzz.

 

[Doink]

can i ask something...if there is a knocking detected in turbo charged cars when boosting...how to find a way to resolve it?

 

[evopilot]

genrally retard timing, watch your EGT if u have it installed, add some fuel and try to get your target AFR, if not add a little more. it'll be a good idea or option if your car has an inbuilt knock monitor and always use an external one to double check and yes, knocking can be also heard by our ears but dat is leddi not good if can just hear by our ears. i would say knock sure got, but how much is good and bad ? imho, just dun go too far ah, and also reducing boost levels will help out and probably also check and make sure the ignition system is properly setup + spark plug gaps too. always try to tune around hot afternoon so dat will help to eliminate some knock during other driving times and conditions. hope this helps n if wrong pls do correct yah hehehe .. just my opinion :)

 

[e819]

any solution 4 me??