Knock Sensor

theodd001 · Post by **theodd001** » Wed Jan 27, 2010 11:43 am

I'm new to Hondata and have got it installed and have a decent calibration running. Before I got the S300 I'd every now and then get an engine light come on because of the knock sensor when I was at full load. Now with the S300 I can data log so I was wondering if anyone could take at look at this and tell me what's causing the knock and if it's a concern or not? Thanks.

newsoltsc · Post by **newsoltsc** » Wed Jan 27, 2010 2:38 pm

If it's on a p28 ecu; there is no knock sensor and it should be disabled in the s300.

From what I've read on knock sensors on this forum :)

theodd001 · Post by **theodd001** » Wed Jan 27, 2010 11:17 pm

I have a P72 ECU. It is the knock sensor coming in. Its seems to happen when I suddenly let off the gas pedal.

fly_n · Post by **fly_n** » Thu Jan 28, 2010 1:16 am

Its happening when u get on the gas.
Not an overwhelming amount of knock,its probably not audible,but still should be addressed,good chance its not even knock...

U should post your calibration & give some details about the type & setup of the motor that the knock sensor is listening to,thats makes it a lot easier for people to pick out any problems.

theodd001 · Post by **theodd001** » Thu Jan 28, 2010 3:26 am

Thanks fly... Well I have a 93 H23 Si...
-Head is mildly ported
-Golden eagle cam gears set to zero, ignition timing set to 16
-Cold air intake
-High flow cat
-Tanabe cat back exhaust
-Fidanza 8lb flywheel
-Walbro fuel pump
-Holley FPR, set to 38psi at idle
-P72 ECU with S300

fly_n · Post by **fly_n** » Thu Jan 28, 2010 6:45 am

I know very little about H23's so i cant really help u there,but, i would hazard a guess at it actually not being knock.

The problem u might be dealing with,is the fact that the knock frequencies which the sensor is listening for are characteristic to the type of motor,displacement of the motor,etc,etc.

So considering your using a B18 knock board(P72) to try to detect knock frequencies in a H23,well u can see what im driving at......

Could also be other forms of false detection,like,for example,something as simple as how u wired the sensor or the fact that they are notoriously fickle.

Dont just ignore it though on my untrained advice,read & keep an eye on your plugs to see if they tell u anything,or get a pro to give it a quick once over,but definitely dont lose sleep over the issue.most people would have just ticked that little check box in parameters/misc. by now & just disabled it .....

Also calibrate your TPS properly,somethings out of order there.

theodd001 · Post by **theodd001** » Thu Jan 28, 2010 2:04 pm

Thanks again fly_n... What tells you that my TPS needs adjusting?

fly_n · Post by **fly_n** » Thu Jan 28, 2010 2:55 pm

i cant remember what the calibration figures u had set were on the TPS tab in your cal,but i remember them being large-ish? & the simple fact that your TPS is only showing as 90% max in your datalogs.
i dont know how well your car is running or idling,etc,u never mention anything about it,so it might be ok.

maybe u just have some weird setup or something with custom throttle cable due to H23 in EG &/or aftermarket throttle body,etc,etc,
but it might be worth checking what your actual throttle plate position is compared to the data your TPS is spitting out or similar.

theodd001 · Post by **theodd001** » Fri Jan 29, 2010 3:24 am

Ahh i see, i didn't notice that before thanks. I'll look at that!

fly_n · Post by **fly_n** » Fri Jan 29, 2010 6:58 am

possibly,maybe u just found your lost mobile phone or wallet.....
its stuck down there under your fast switch....

or maybe u can finally remove that sabotage device your buddy stuck to the back of your gas pedal while u werent looking, in the staging lanes between runs, last time u lined up against him down at the strip.....

theodd001 · Post by **theodd001** » Fri Jan 29, 2010 2:30 pm

Today I tried putting the TPS settings to default and my car idled about 200 rpms higher than normal and after reving the rpms would come down to about 1300 then slowly drop down to 1050... So I don't know what's going on there... The way I have the settings now, the engine idles at 850 and after I rev it, it drops right back to 850.

hdragster · Post by **hdragster** » Fri Jan 29, 2010 4:05 pm

theodd001 wrote:Today I tried putting the TPS settings to default and my car idled about 200 rpms higher than normal and after reving the rpms would come down to about 1300 then slowly drop down to 1050... So I don't know what's going on there... The way I have the settings now, the engine idles at 850 and after I rev it, it drops right back to 850.

Will if your car is cold and it idles high that normal but if your car idles high when your car is already warm there is a problem. My best suggestion is just mess around with your IAC (Idle Valve Control) increase or decrease it that should fix your idle problem. LMK if it works

fly_n · Post by **fly_n** » Fri Jan 29, 2010 5:24 pm

yup that'll definitely fix it lol.......

spose it depends on your definition of the word 'fix'......

theodd001 · Post by **theodd001** » Fri Jan 29, 2010 10:46 pm

hdragster wrote:
theodd001 wrote:Today I tried putting the TPS settings to default and my car idled about 200 rpms higher than normal and after reving the rpms would come down to about 1300 then slowly drop down to 1050... So I don't know what's going on there... The way I have the settings now, the engine idles at 850 and after I rev it, it drops right back to 850.
Will if your car is cold and it idles high that normal but if your car idles high when your car is already warm there is a problem. My best suggestion is just mess around with your IAC (Idle Valve Control) increase or decrease it that should fix your idle problem. LMK if it works

Yeah when my car is cold the Thermal Idle Control Valve keeps the throttle bypassed untill the engine comes up to normal operating temp at which point the little plunger in this valve expands enough and stops bypassing the throttle and my engine idles at 850rpm... But I will try messing around with IAC.