false knock driving me crazy.
11-09-2007, 06:18 PM
#1
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false knock driving me crazy. I got false knock like crazy right now during normal driving, its logging like up to 40 degrees of knock retard. I know this **** is false because I cant hear a damn peep of a ping and with 20 or more degrees I should be hearing some pinging that snuck through. Its probably from my x-pipe setup along with the cammed motor and the vibrating driveline that is causing this. Ill just be driving along no more than 30% throttle and its logging *** loads of knock. What is the simplest way to shut those damn sensors off, I have desensitized them but i want them off. Anyone know how?
AFR is good and all that.
I am tempted to unplug those stupid sensors and delete the codes.
AFR is good and all that.
I am tempted to unplug those stupid sensors and delete the codes.
Last edited by brad8266; 11-09-2007 at 06:24 PM.
11-09-2007, 06:44 PM
#2
I would put an oscilloscope on the knock sensor wires, and drive it.
My whole deal with eliminating, or desensitizing the knock sensors, is you better be damn sure it aint pingin.
The way I would do it in my shop, is to first try and find the source of the knock signal, if there is one. So, first you need to scope the sensors to see if there really is a knock signal.
Then, next thing would be to drive it with the scope hooked up, and a 5 gas analyzer to monitor the NOX levels. If the NOX is real low, you know its false. If its in excess of 2000 ppm, then you have some work to do, both in tuning and trying to find a sweet spot in the timing and A/F that will bring the NOX level down.
I know most people dont have the equipment to do such testing, but at the same time, you really cant start turning off stuff like KR without having a detailed picture of whats going on.
One of the problems with tuning in general is most people dont have the equipment or resources to properly diagnose, and then set up a tune.
In your case most people would say **** it and turn off the KR, because they dont hear knock, never realizing that there could be elevated combustion temps, that could be detrimental to the life of your engine.
My whole deal with eliminating, or desensitizing the knock sensors, is you better be damn sure it aint pingin.
The way I would do it in my shop, is to first try and find the source of the knock signal, if there is one. So, first you need to scope the sensors to see if there really is a knock signal.
Then, next thing would be to drive it with the scope hooked up, and a 5 gas analyzer to monitor the NOX levels. If the NOX is real low, you know its false. If its in excess of 2000 ppm, then you have some work to do, both in tuning and trying to find a sweet spot in the timing and A/F that will bring the NOX level down.
I know most people dont have the equipment to do such testing, but at the same time, you really cant start turning off stuff like KR without having a detailed picture of whats going on.
One of the problems with tuning in general is most people dont have the equipment or resources to properly diagnose, and then set up a tune.
In your case most people would say **** it and turn off the KR, because they dont hear knock, never realizing that there could be elevated combustion temps, that could be detrimental to the life of your engine.
11-09-2007, 06:54 PM
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Well the knock wasnt really there unitl the last time I pulled the clutch out and put a new one in. I suspect that had something to do with it from moving **** around like the exhaust. I will probably run another seafoam can through and replace the plugs before I make any crazy changes.
I have sprayed my 150 shot on it too recently and it was OK, I mean if the knock was so bad and real it would have destroyed the motor when i sprayed.
Plus when im in 4th gear the car/driveline doesnt vibrate so much and the knock goes away in that gear.
I do have an Oscope to use though.
I have sprayed my 150 shot on it too recently and it was OK, I mean if the knock was so bad and real it would have destroyed the motor when i sprayed.
Plus when im in 4th gear the car/driveline doesnt vibrate so much and the knock goes away in that gear.
I do have an Oscope to use though.
11-09-2007, 06:57 PM
#4
Well I don't have any of Ed's sweet whizmo-thingies 
but in an extreme case like this, I would run the car down low in fuel and refuel with a few gallons of race fuel and log... I'm not talking about WOT, log cruise because unlike WOT, CL operation will keep the car near stoich, and you can use that to rule out that variable (AFR).
but in an extreme case like this, I would run the car down low in fuel and refuel with a few gallons of race fuel and log... I'm not talking about WOT, log cruise because unlike WOT, CL operation will keep the car near stoich, and you can use that to rule out that variable (AFR).
11-09-2007, 07:03 PM
#7
Well the knock wasnt really there unitl the last time I pulled the clutch out and put a new one in. I suspect that had something to do with it from moving **** around like the exhaust. I will probably run another seafoam can through and replace the plugs before I make any crazy changes.
I have sprayed my 150 shot on it too recently and it was OK, I mean if the knock was so bad and real it would have destroyed the motor when i sprayed.
Plus when im in 4th gear the car/driveline doesnt vibrate so much and the knock goes away in that gear.
I do have an Oscope to use though.
I have sprayed my 150 shot on it too recently and it was OK, I mean if the knock was so bad and real it would have destroyed the motor when i sprayed.
Plus when im in 4th gear the car/driveline doesnt vibrate so much and the knock goes away in that gear.
I do have an Oscope to use though.
It would only hurt the motor on spray, if it wasnt pulling the timing out.
In other words, if you had crazy knock counts, and it was retarding your timing, like it should have been, then it wouldnt hurt the motor, unless you had so much timing in it to overide the knock retard.
anything I tune, that has KR out of the ordinary, gets tested with the 5 gas. All the FI tunes I do, 5 gas. Big cam motors, 5 gas, more for idle tuning on them though.
It is a vital piece of equipment as far as I'm concerned. Dont know why more tuners dont use them. They're better than EGTs for tuning.
If you need any o-scope pointers, let me know. I've got over 15 years exp using o-scopes to diag electrical problems. Also have enough info and stored waveforms to write a book.
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11-09-2007, 07:16 PM
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Thanks guys. I guess Ill give myself a few more days to sort it all out first. Too bad I dont have one of those high speed 5 gas things.
11-09-2007, 09:59 PM
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And out of my impatientce and boneheadness I went out and reflashed the PCM with the knock retard noise multipliers set up to 4 and took it for a ride. I am now logging no knock retard and I could not hear any audible ping at all either when cruising/normal driving or at WOT. The car seems to run a lot better then it was. Feels way more snappier and easier to drive, especially when i shift. AFR is still ok.
I will still be doing more troubleshooting anyway, once I get this tank of gas low i will put some 100 in since we have a local unleaded 100 pump around the corner.
Mods are built shortblock, TEA heads, medium cam, normal boltons.
I will still be doing more troubleshooting anyway, once I get this tank of gas low i will put some 100 in since we have a local unleaded 100 pump around the corner.
Mods are built shortblock, TEA heads, medium cam, normal boltons.
