Knock Sensors with T/S and stroker

[KIM_05_GT]

Who has them turned on? and off? Why?



Thanks

 

[Royski]

I don't know why you would want them off. My tuner has them on and uses them as a guide when tuning the car.

 

[klaw]

The knock sensors and related software are designed specifically around the knock signal patterns generated by the stock engine. It's not difficult to imagine that modifications like superchargers, cam profile, phasor limiters, and longer crank stroke could change the sound/vibration environment that the knock sensors are trying to interpret. The sensors are only useful if they're able to accurately sense true knock. False positives (where the sensors signal a knock condition that isn't actually happening) will result in pulled timing etc where it isn't required. Conversely false negatives (where the sensors fail to detect an actual knock condition) could lead to catastrophic failure by providing a false sense of security. Obviously, only the owner and tuner can decide if they believe the sensors for a given build and prefer to rely on them; or don't and turn them off and tune the engine with an extra safety margin (less timing and/or more fuel) to avoid knock. This issue is particularly important for owners of high HP builds - absolute trust in the knock sensors is probably not a good idea.

 

[05stroker]

Mine have been turned of by every person that has tuned my strokers . Most of the time if I do not then the car goes crazy on the dyno and wont make a full pull . That being said , I do not have one of those noisy when cold strokers either . I have never heard anything knocking unless something was messed up. I dont know if its the big Procharger , LTs or what but mine have always been turned off .

 

[ILW84U]

Mine have been turned of by every person that has tuned my strokers . Most of the time if I do not then the car goes crazy on the dyno and wont make a full pull . That being said , I do not have one of those noisy when cold strokers either . I have never heard anything knocking unless something was messed up. I dont know if its the big Procharger , LTs or what but mine have always been turned off .

My guess it is the big Procharger. When I went from the P1 to the D1 mine had to be turned off. The sensor signal on the Procharger side was more than double the other.

 

[05stroker]

My guess it is the big Procharger. When I went from the P1 to the D1 mine had to be turned off. The sensor signal on the Procharger side was more than double the other.

That would be my guess as well . If you ever have held your hand on top of a Procharger while the car is running , it doesnt feel very smooth at all.

 

[RONAELEGT550R]

The knock sensors and related software are designed specifically around the knock signal patterns generated by the stock engine. It's not difficult to imagine that modifications like superchargers, cam profile, phasor limiters, and longer crank stroke could change the sound/vibration environment that the knock sensors are trying to interpret. The sensors are only useful if they're able to accurately sense true knock. False positives (where the sensors signal a knock condition that isn't actually happening) will result in pulled timing etc where it isn't required. Conversely false negatives (where the sensors fail to detect an actual knock condition) could lead to catastrophic failure by providing a false sense of security. Obviously, only the owner and tuner can decide if they believe the sensors for a given build and prefer to rely on them; or don't and turn them off and tune the engine with an extra safety margin (less timing and/or more fuel) to avoid knock. This issue is particularly important for owners of high HP builds - absolute trust in the knock sensors is probably not a good idea.

Yeah, what he said!

My builder said the same thing. with the radical cams and builds these days the engine knock sensors can sense false knocks. if you are running a stock block and bottom end with mild cams you might could get away with using them.

 

[dysan]

I've got a real smooth 302 stroker @ 9.3:1 compression and I had to have the knock sensors turned off. I could feel the difference in power from time to time and when I logged the knock spark adder, I could see it going all over the place.

 

[GI Joe]

my block has no provisions for knock sensors...had to remove them..

 

[Jordan@JPC]

To echo some of the other comments, the human ear is better than any super-sophisticated knock sensor out there. Knock sensors are just microphones, and the computer is used to identify signal patterns that resemble knock. So, they're far from perfect and can sometimes get in the way if other mechanical noise is present because the computer will keep yanking timing when it really shouldn't be.

I don't think they're entirely useless either though, you can do some cool things with knock sensors even if they aren't being used to retard timing. If your radio head unit has an auxiliary input, with a few radio shack parts you can pipe the knock sensor output through your stereo. Or, you can hook the output up to your laptop and record sound clips to review later. In my opinion, that works better than any knock sensor system I've ever seen, and its cool to show your gearhead buddies too haha.

 

[dysan]

Heh...now that's a cool idea for the knock sensors.

 

[Hatchman]

Do knock sensors have to be turned all the way off, or do they have a threshold setting which can be turned down in the tune, so it would require a "louder knock" in order to have them retard timing? In other words, can you just turn them down or do you have to turn them off?

 

[one eyed willy]

i got a question sfor ya...anyone have a pin out of the knock sensor plug? i have one knock sensor that goes crazy...number 1 and the other one is fine,since i removed the sensors when i rebuilt the engine, i dont know if the number 1 sensor is in the number 1 spot or if it even matters. my sensors are not turned off, my tuner just made it so they dont pull as much timing as they want to , he limited the amount of timing they can actually pull. so i was thinking if i could just pull the number 1 knock sensor off the block i could fix my knocking issue with the sensor, or maybe there is a problem with it i can see. im just not sure which one is the actual number 1 sensor.

 

[05stroker]

i got a question sfor ya...anyone have a pin out of the knock sensor plug? i have one knock sensor that goes crazy...number 1 and the other one is fine,since i removed the sensors when i rebuilt the engine, i dont know if the number 1 sensor is in the number 1 spot or if it even matters. my sensors are not turned off, my tuner just made it so they dont pull as much timing as they want to , he limited the amount of timing they can actually pull. so i was thinking if i could just pull the number 1 knock sensor off the block i could fix my knocking issue with the sensor, or maybe there is a problem with it i can see. im just not sure which one is the actual number 1 sensor.

Pass side is bank 1 . From what I have seen all engines have bank 1 on the same side as the #1 plug.

 

[one eyed willy]

Pass side is bank 1 . From what I have seen all engines have bank 1 on the same side as the #1 plug.

yeah...but did i put the original sensor back in the original spot...lol,im not sure if i did,i didnt mark them,im wondering if there is a way to figure it out by looking at the plug.

anyone know if you will get a code if you just unplug the knock sensors?

 

[lito]

yeah...but did i put the original sensor back in the original spot...lol,im not sure if i did,i didnt mark them,im wondering if there is a way to figure it out by looking at the plug.

anyone know if you will get a code if you just unplug the knock sensors?

One wire is shorter than the other, you still can install them backwards but it is not common (as the front O2s for example).

Yes there is a DTC but I don't think it lights the MIL. I've seen people mixing CMCVs and knock sensors together, they share the same connector in the same aera and the only difference is that the knock sensors use 4 wires and the CMCV 3.

 

[05stroker]

yeah...but did i put the original sensor back in the original spot...lol,im not sure if i did,i didnt mark them,im wondering if there is a way to figure it out by looking at the plug.

anyone know if you will get a code if you just unplug the knock sensors?

I have always put the longer side to the drivers side.

 

[one eyed willy]

great, so they are probably in the correct spot,ill check it out,would there be any harm in just taking them out of the block and suspending them somehow(if i cant find the problem)?thanx guys.

 

[05stroker]

great, so they are probably in the correct spot,ill check it out,would there be any harm in just taking them out of the block and suspending them somehow(if i cant find the problem)?thanx guys.

If you are turning them off in the tune then you can remove them . Just unbolt them from the block and disconnect them behind the pass side head and remove them . If you cannot get to the sensor right now then just unplug them behind the head . Or just leave them with them shut off in the tune . Im not sure what it would do if they are removed or disconnected and left on in the tune . I would assume just a CEL , but that would be a question better for Lito to answer as Im unsure.

 

[lito]

Yes, probably just the DTC, giving it a little thought maybe the cars I've seen with that fault had the MIL disabled in the tune (some great tuners love to do that ;-) ).

Regarding the logic I'm not sure but if they are not present they won't cause it to fall into any protection mode but if the tune has calibrated some advance authority in them you may feel that because you may be missing a couple of degrees in some areas.

Have you checked in your logs if there is some piston slap detect as knock while idling cold?