My car is pulling timing everytime I get on it. Seems that broken motor mounts will cause the knock sensors to activate.
Anyways, here is some useful info for the rest of us:
http://www.svtperformance.com/forum...297141-knock-sensors-wheel-hop-vs-timing.html
Anyways, here is some useful info for the rest of us:
http://www.svtperformance.com/forum...297141-knock-sensors-wheel-hop-vs-timing.html
99-01 Cobras come equipped with knock sensors, not sure about the 96-98 Cobras and Mach 1s.
I was out working with a car with knock sensors over the weekend. In a nutshell, with the stock knock sensor parameters...a knock sensor equipped car can pull up to 6 degrees of timing when the sensor(s) activate. There is a retard rate, which determines how quickly the timing is pulled out. In stock form, the EEC will pull out one degree of timing every 1/4 second. Wheel hop will activate knock sensors.
There is an advance rate, which determines how quickly the timing is put back in the motor when no knocking is detected. One degree will be added in per X amount of seconds. In stock form, there is a "blending ramp" for timing advance. The more RPM the motor sees, the quicker the timing will come back in.
There is one more table called advance limit. Care must be taken not to populate this table with anything greater than 0. When the knock sensors are not going off, the EEC will try to advance timing when looking at this table. In stock form, this table is populated with positive values in some RPM areas. You may be in for a nasty surprise if you add timing in another area of the tune, and forget to set the knock advance table to zeros.
No. Traction control has no effect.
In a 99 Cobra ZMR2 processor, the EEC will begin to "look" at the knock sensors at 120 degrees.
Good information to have, just earlier today I was thinking on how driveline vibration can affect knock sensors. It appears that when the frequency of the vibration is in the range that the sensors read (actually, the knock sensors report everything that can be interpreted as spark knock, whether it is or not. The engine controller is programmed to choose what input from knock sensors to act upon)as spark knock, then timing will be reduced, lowering performance. Modern knock sensors do seem to be more finely tuned than the earlier ones, which could sometimes read high frequency vibration from an aggresive tire pattern as spark knock. Incidentaly, the Mach1 engine does have the knock sensors, they're located in the valley under the intake manifold.
I've heard of false positives that the knock sensors pick up from other things vibrating. Just kind of surprised that wheel hop would make the same sound.
Double hit - not only do you have no traction, but you're down on power as well.
If you've got a supercharger on your 99-01 just get a GOOD tune, turn the knock sensors off, run only good name brand 93 octane, listen for detonation.
My tuner turned the knock sensor off, but you can still log knock sensor with the Xcal2 to see what they would be doing, and the timing pulled is all over the place throughout a WOT pull, glad mine are off.
Yes, it is possible to "turn the knock sensors off". There are a couple of ways actually. But, you have to be aware of a few things.
One way to turn them off is by a switch under scalars. It is much like the method that the rear O2 sensors are turned off.
Another is engine temperature related. There is a threshhold at which the EEC looks for to begin using the knock sensors to change timing. Setting this higher than the engine's operating temperature will disable the sensors.
The third is to populate the knock sensor advance and retard rate tables with all zeros.
When setting a knock sensor equipped car's timing tables up for best performance, a tuner must take care to populate the advance rate tables with all zeros. When the EEC sees no reading from the knock sensors in the stock tune, it will ADVANCE timing. If a tuner sets up timing to be higher than stock in other areas (borderline knock table) and neglects the advance from the knock sensor tables...it is possible to see advanced timing beyond what is being commanded in the borderline table. That is one little way to add some unforseen timing and possibly make something go pop.
-"03Steve" under Reggie's screenname-
I can tell when I set mine off. It it only would happen when there was a huge shock to the drivetrain.
Oh, I noticed it alot when my motor mounts where broke... if that has anything to do with it.
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