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