Knock Sensor

bowez

Registered User
Curious how the EEC respond to the Knock Sensor missing, am I right in assuming it pulls all the timing it can?

Also has it be figure out if the 94/95 KS will supply the correct output to the 89-93's? Looking at the PNs the 94/95s are for the 4.6.

F3LY-12A699-A which has a resonant Hz of 6.15k
vs the 89-93
E9SZ-12A699-A which has a resonant Hz of 5.7k

The threads are no big deal the SZ is 10x1.5 and the LY is 12x1.5 so it could just be retapped.
 
You need to use the same sensor part number that you pulled from the car, you just can't throw in any sensor.

If you unplug the sensor, then the computer automatically pulls the 8 degrees of timing as soon as you are in the load and rpm range the computer normally monitors the knock sensor. Which is about 1/3 throttle or more and before you go into boost.

To deactivate this, you need to have a chip.

Fraser
 
If you unplug the sensor, then the computer automatically pulls the 8 degrees of timing as soon as you are in the load and rpm range the computer normally monitors the knock sensor. Which is about 1/3 throttle or more and before you go into boost.

To deactivate this, you need to have a chip.

Fraser

That isn't what Dalke told me.
 
I am running with the knock sensor unplugged. My understanding is that unplugged it doesnt work at all

Ken
 
I had attempted a repair on mine (snapped the connector off) during the engine swap, so I figure either my use of Pb based solder instead of Ag may have broken the connection or I reversed the connections.

If using the 4.6 KS is just a simple retune it make getting KSs alot easier.
 
Rather than get argumentative with Fraser, you guys might want to listen to what he says, and ask intelligent questions to learn the answer and/or the truth.

The exact programming in the SC EEC's has been a mystery for years. Sure you can read Charles Probst's book and/or you can listen to the word of many self proclaimed (and otherwise) Ford engineers and experts from over the years, but in the end, none of the above (or any other up to now) sources have had access to, known, or understood all the programming in the SC EEC.

The exact coding of the EEC took leap years forward when I obtained copies of the ACTUAL documents that were used to record the programming that is actually in our specific EEC's (not some plagiarized Mustang documents, either). I obtained these document during the summer of 2008 from a "closet" SC enthusiast who will forever remain anonymous. But even so I do not understand the coding langauge of the EEC so even being in possession of said documents was of limited value to me (us). Over the past year and half, Fraser (the computer language and programming expert) has been working on the EEC coding via these documents. There are so many lines of code that it simply isn't practical (or maybe even possible) to go through it line for line and make sense of all of it, so Fraser and I have worked on areas that needed explanation and in the process have discovered a multitude of things that were previously thought to be different, or not even known to exist.

With Fraser's background in computer programming and my background in engine mechanics, tuning, and dyno testing, we have arrived at many conclusions that were not known or accepted in the past. As a result we can now do a lot more "tuning" and a lot less "hacking" with the EEC. Most people will never appreciate or understand the work that Fraser and I have gone through to make this all available and useful to you (as a group) but the bottom line is this:

If Fraser says something about the inner workings of the EEC, you can pretty much rest assured the he and I have discussed it, and probably worked together to come to whatever conclusion is being presented. Feel free to ask questions of either of us, and if we don't seem to agree on something, it's probably because someone, somewhere, isn't understanding fully.

In the case of the knock sensor specifically, it was partly your car, Mitchell, at the Shootout this year that started us digging deeper into the knock sensor strategy. We already knew how it worked, but we weren't aware that unplugging the sensor would initiate full knock retard. When I saw how much faster your car was with a 50hp shot of nitrous, I started to hypothesize that it was already running full knock retard to the point that the car simply wouldn't run without the nitrous to speed up combustion. Chris Vining experienced a similar effect several years ago but I did not make the connection at the time. After the Shootout I asked Fraser to look through the code, and sure enough that is exactly what the code tells the EEC to do.

So now that you know that, you can realize that you shouldn't simply unplug the knock sensor. Ultra high performance SC's should be tuned with the knock sensor turned off and extreme caution should exercised not to detonate the motor.
 
"Knock Sensor, we don't need no stinking knock sensor"
Actually, I wish I had provision for a knock sensor on my Mustang EEC, but I will live on the edge.
 
So that being said is it possible that the KS is causing my hard start issues? Also if the 94/95 are running the 4.6 KSs (and it just not a misprint) would it not be beneficial for the whole community if we all could run that one since it is still in production.

Double checked the numbers (at Autozone's site) and F3LY-12A699-A is listed for the 94 MrkVIII and 94 SC which is in line with what Ford tried to give me last year for my 93.

I'm not that familiar with EEC coding but couldn't you just compare the same areas of the code to see what Ford did to deal with change the Resonate Frequency?
 
I'm not getting argumentive, just stating what your answer was to my question a while back when the local tuner I was using was getting stumped with my car. Now that some different info has been learned I'll use it and what you relayed to me at the end of the Shootout to hopefully get my car "tuned" properly.

Frazier, I apoligize to you for doubting your info, thanks for figuring out this problem.

Dave, what you said about my car at the Shootout sounds pretty dead on, how else do you explain picking up 1.2 seconds on a 50 shot of nitrous.
Rather than get argumentative with Fraser, you guys might want to listen to what he says, and ask intelligent questions to learn the answer and/or the truth.



In the case of the knock sensor specifically, it was partly your car, Mitchell, at the Shootout this year that started us digging deeper into the knock sensor strategy. We already knew how it worked, but we weren't aware that unplugging the sensor would initiate full knock retard. When I saw how much faster your car was with a 50hp shot of nitrous, I started to hypothesize that it was already running full knock retard to the point that the car simply wouldn't run without the nitrous to speed up combustion. Chris Vining experienced a similar effect several years ago but I did not make the connection at the time. After the Shootout I asked Fraser to look through the code, and sure enough that is exactly what the code tells the EEC to do.

So now that you know that, you can realize that you shouldn't simply unplug the knock sensor. Ultra high performance SC's should be tuned with the knock sensor turned off and extreme caution should exercised not to detonate the motor.
 
Rather than get argumentative with Fraser, you guys might want to listen to what he says, and ask intelligent questions to learn the answer and/or the truth.

The exact programming in the SC EEC's has been a mystery for years. Sure you can read Charles Probst's book and/or you can listen to the word of many self proclaimed (and otherwise) Ford engineers and experts from over the years, but in the end, none of the above (or any other up to now) sources have had access to, known, or understood all the programming in the SC EEC.

The exact coding of the EEC took leap years forward when I obtained copies of the ACTUAL documents that were used to record the programming that is actually in our specific EEC's (not some plagiarized Mustang documents, either). I obtained these document during the summer of 2008 from a "closet" SC enthusiast who will forever remain anonymous. But even so I do not understand the coding langauge of the EEC so even being in possession of said documents was of limited value to me (us). Over the past year and half, Fraser (the computer language and programming expert) has been working on the EEC coding via these documents. There are so many lines of code that it simply isn't practical (or maybe even possible) to go through it line for line and make sense of all of it, so Fraser and I have worked on areas that needed explanation and in the process have discovered a multitude of things that were previously thought to be different, or not even known to exist.

With Fraser's background in computer programming and my background in engine mechanics, tuning, and dyno testing, we have arrived at many conclusions that were not known or accepted in the past. As a result we can now do a lot more "tuning" and a lot less "hacking" with the EEC. Most people will never appreciate or understand the work that Fraser and I have gone through to make this all available and useful to you (as a group) but the bottom line is this:

If Fraser says something about the inner workings of the EEC, you can pretty much rest assured the he and I have discussed it, and probably worked together to come to whatever conclusion is being presented. Feel free to ask questions of either of us, and if we don't seem to agree on something, it's probably because someone, somewhere, isn't understanding fully.

In the case of the knock sensor specifically, it was partly your car, Mitchell, at the Shootout this year that started us digging deeper into the knock sensor strategy. We already knew how it worked, but we weren't aware that unplugging the sensor would initiate full knock retard. When I saw how much faster your car was with a 50hp shot of nitrous, I started to hypothesize that it was already running full knock retard to the point that the car simply wouldn't run without the nitrous to speed up combustion. Chris Vining experienced a similar effect several years ago but I did not make the connection at the time. After the Shootout I asked Fraser to look through the code, and sure enough that is exactly what the code tells the EEC to do.

So now that you know that, you can realize that you shouldn't simply unplug the knock sensor. Ultra high performance SC's should be tuned with the knock sensor turned off and extreme caution should exercised not to detonate the motor.

So I guess im a little behind here? I didnt tune the car before the shootout but did run it on the dyno with the knock sensor pulled. Am I to understand now that I pulled 340RWHP with the timing being pulled. I was told it just disables the sensor. Wasnt trying to be argumentitive here but just passing on my own understanding from what I told.

Ken
 
So that being said is it possible that the KS is causing my hard start issues? Also if the 94/95 are running the 4.6 KSs (and it just not a misprint) would it not be beneficial for the whole community if we all could run that one since it is still in production.

Double checked the numbers (at Autozone's site) and F3LY-12A699-A is listed for the 94 MrkVIII and 94 SC which is in line with what Ford tried to give me last year for my 93.

I'm not that familiar with EEC coding but couldn't you just compare the same areas of the code to see what Ford did to deal with change the Resonate Frequency?

No the KS won't cause a hard start since the EEC is not paying attention to it at start up.

The resonance frequency is built into the knock sensor itself, which is why you need to specifically match the new one to the old one, or you will end up with false signals. I think there is about 3 or 4 different frequencies the SC's had installed from what Dave has told me.

The knock sensor systems we have in the SC's are actually a marvel of simplicity, but have one big problem. You start changing the "tone" of your motor by doing upgrades, it becomes a hindrance and the only thing you can do is shut it off in the tune.

Because the EEC's we have are not exactly super fast computers, they can only do knock sensing in a very simple way, ie having a sensor that rings the EEC at a certain frequency and even then, the EEC only takes a quick listen to the knock sensor during a short little window where it predicts it could hear a detonation event based on the spark timing and what cylinder is being fired at that time. If the EEC picks up a ring from the knock sensor, it assumes detonation and starts pulling timing, and as each following ring is detected at each window it pulls more timing until the max allowed that is setup in the tune, which is typically 8 degrees. If it detects so many no ring windows then it starts to advance timing until no retard is left.

Now with that in mind here's an example of the draw back to this simple system, you go ahead and change the valve train, you just changed the "song" of the motor so to speak, and it could cause a resonance that triggers the knock sensor to ring the EEC, and that resonance could be the intake roller rocker from #3 cylinder and you have just lost 8 degree's of timing. It seems the factory somehow did do a quick check on each motor to discover its resonance frequency and is why we'll see several different "part" numbers for sensors in our cars.

As a fail safe, if the EEC doesn't see an active signal from the KS after so many engine cycles, it'll automatically pull the max amount of retard anytime the motor goes into the operating range of the Knock sensor, which on the stock tune of the SC is approximately above 50% load, 700 to 5000 rpm's and above 170F ECT.

This is why you'll here of folks who unplugged the KS in the old days bragging about 32 and higher degrees of timing and not blowing up the motors... they where actually only getting about 24 degree's of timing. Sadly, some folks have tried that amount of timing and lost the gamble with the KS active, but the song of the motor had changed and didn't trigger the KS.

Newer knock sensor systems have the EEC itself continuously listen and it can monitor at a wide range of frequencies, and is more along the lines of an active sensor system instead of a passive system like ours.

Fraser
 
cars.

As a fail safe, if the EEC doesn't see an active signal from the KS after so many engine cycles, it'll automatically pull the max amount of retard anytime the motor goes into the operating range of the Knock sensor, which on the stock tune of the SC is approximately above 50% load, 700 to 5000 rpm's and above 170F ECT.

This is why you'll here of folks who unplugged the KS in the old days bragging about 32 and higher degrees of timing and not blowing up the motors... they where actually only getting about 24 degree's of timing.


Fraser

So my question Fraser is the 340rwhp I pulled on the dyno without the knock sensor hook up was with 8 degrees of timing pulled? I was originally told that pulling the plug and running 100 octane gas I was safe from detonation. I am only running 24 degrees of timing. If what you say is true than the computer pulled 8 degrees to 16 and I pulled 340 RWHP. Is that correct? Im just trying to get a handle on this new information.
 
Yeah I did some more looking and saw there are 3 KS PNs 89-91, 92/93, and 94/95.

Sounds like I either need to find a 93 KS, or get the chip to ignore it (which is probably the best solution for long term modding).

Though speaking just in theory for "safety" and availability since the 94/95 use a 4.6 KS could not every SC be updated to 94/95 programming with no more ill effects than a 94/95 experiences with it stock KS program. I know the best option would be to find the resonance of motor but that anit going to happen, adapting a active system with a more modern EEC would be more likely to happen.
 
Ken, I would not assume anything. However, your car ran 12.8 @ 105mph when it should have been running about 6-8mph faster. As always there are other factors that could be playing into that, but the car is slower than it should be.

If your car really had 340rwhp it would have run a lot faster than it did. Paul Matthew's car ran about the same time as yours and he made about 260rwhp on the dyno. Kurt Kreisz car makes about 360rwhp and he ran well into the 11's.

Clearly your car needs tuning but without live data, it's anybody's guess what is really going on.
 
Yeah I did some more looking and saw there are 3 KS PNs 89-91, 92/93, and 94/95.

Sounds like I either need to find a 93 KS, or get the chip to ignore it (which is probably the best solution for long term modding).

Though speaking just in theory for "safety" and availability since the 94/95 use a 4.6 KS could not every SC be updated to 94/95 programming with no more ill effects than a 94/95 experiences with it stock KS program. I know the best option would be to find the resonance of motor but that anit going to happen, adapting a active system with a more modern EEC would be more likely to happen.

The 94/5 sensor would be a poor choice for a performance engine. As Fraser said, our knock sensor strategy is simply incapable of adapting to a modified motor. I guess if you want to run the car without a chip or an active sensor you could plug it in and move it away from the motor. But seriously, if you are doing things to the motor that make it incompatible with the stock sensor and don't have a chip or tuning ability then - well - good luck to you.
 
So my question Fraser is the 340rwhp I pulled on the dyno without the knock sensor hook up was with 8 degrees of timing pulled? I was originally told that pulling the plug and running 100 octane gas I was safe from detonation. I am only running 24 degrees of timing. If what you say is true than the computer pulled 8 degrees to 16 and I pulled 340 RWHP. Is that correct? Im just trying to get a handle on this new information.

It could have been a simple thing like ECT's never went above 170F during that dyno pull, so during that time there was no spark pull.

Fraser
 
I do have a chip, well I should, when I bought it former owner said it was. Though not sure as to level of tune that was applied.
 
It could have been a simple thing like ECT's never went above 170F during that dyno pull, so during that time there was no spark pull.

Fraser

So during my 1/4 mile runs the timing is or was being pulled in your opinion? Will the knock sensor need to be plugged in prior to my tuning the new engine and shut off by the tuner. I know the engine wasnt tuned before racing and it is inmateral since I wasnt out to set any records. Need to know some of this stuff to keep up with the big dogs

Ken
 
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