spark knock/detonation

[Wicked_Sludge]

actually, they were talking about cam timing, not ignition timing.

 

[Bob Ayers]

actually, they were talking about cam timing, not ignition timing.

Well, the first post started out about spark knock, and also mentioned valve timing, which are not related at all! Spark knock is usually caused by an over advanced ignition timing. And then your post #3, followed along about valve timing being adjusted by the timing belt, which isn't true at all.
Valve timing can have slight adjustments by an adjustable cam sprocket (or cam gear).

 

[Wicked_Sludge]

spark knock can be caused by quite a few factors...only one of which is ignition timing.

since the ignition timing is usually determined baised on the cams position, changing your cam/valve timing would also change your ignition timing.

 

[Bob Ayers]

spark knock can be caused by quite a few factors...only one of which is ignition timing.

since the ignition timing is usually determined baised on the cams position, changing your cam/valve timing would also change your ignition timing.

Not true again!!! The cam timing has no change on the ignition timing with a 97 2.3L with EDIS. And even the older 2.3L with a distributor was not driven off the camshaft.

 

[Wicked_Sludge]

...since the ignition timing is usually determined baised on the cams position...

 

[Dave R]

...since the ignition timing is usually determined baised on the cams position...

Umm, NO, the ignition timing is solely based on the piston's position in the bore and somewhat relatedly, since the piston is attached to it, the crankshaft's position. When they say "Before Top Dead Center" they ain't talking about the cam.

 

[Wicked_Sludge]

geeze, why are we even argueing about this.

in engines that use cam position sensors or distributors, the ignition timing is based on the CAM timing (which is in turn based on the piston position). only engines with a CRANK position sensor take timing readings directly from the crank.

 

[Bob Ayers]

geeze, why are we even argueing about this.

in engines that use cam position sensors or distributors, the ignition timing is based on the CAM timing (which is in turn based on the piston position). only engines with a CRANK position sensor take timing readings directly from the crank.

Why can't you admit your WRONG?????

There isn't a vehicle made that only has a cam position sensor. They ALL will have a crank position sensor!! The CAM position sensor is only used to detect misfires with an OBD-2 system

Give it a break!!!

 

[Wicked_Sludge]

plenty of newer rigs base spark off the cam position sensor.

and how is a CPS supposed to detect misfires?

 

[Dave R]

plenty of newer rigs base spark off the cam position sensor.

Name a few.

and how is a CPS supposed to detect misfires?

A Cam Position Sensor cannot detect a misfire. A Crank Position Sensor can detect a misfire, it shows up as a frequency change in the output of the sensor.

Speaking only of the Ranger 2.3 system, since that is what I am familiar with, the Cam Position Sensor consists of only one "lump" on the back of the oil pump drive sprocket's belt guide. The Cam Position Sensor only tells the computer when the #1 cylinder is at TDC on the compression stroke, since the Crank Sensor can't tell the difference between one stroke and another. To it TDC is TDC, only the cam dictates which stroke is which. The computer uses that info for injector timing, not ignition timing. You unplug the cam sensor and the engine will still run. It takes it a bit longer to start as it has to guess on injector timing until the engine starts.

 

[Wicked_Sludge]

most rigs utilizing coil-on-plug ignition systems (eg, 4.6 and 5.4's, along with some others) rely on the CMP input to select the proper ignition coil to fire. whether the PCM can adapt and run without this signal, im not sure as ive never tried to run one unplugged.

 

[Dave R]

most rigs utilizing coil-on-plug ignition systems (eg, 4.6 and 5.4's, along with some others) rely on the CMP input to select the proper ignition coil to fire.

Yes, but the computer does not rely on info from the cam sensor to decide WHEN to fire the coil, only which coil to fire.

 

[Bob Ayers]

A Cam Position Sensor cannot detect a misfire. A Crank Position Sensor can detect a misfire, it shows up as a frequency change in the output of the sensor.

The CMP signal is needed, along with the CKP signal to determine a misfire. Here is a good discription on how Fords EDIS operates:

http://rockledge.home.comcast.net/RangerPictureGallery/DIS_EDIS.htm

 

[Dave R]

Good page but it sort of proved our point. DIS does not have a Cam Position Sensor, only a CID.

 

[Wicked_Sludge]

as the page specified, a CID and cam position sensor are the same thing. a "you say tomatoe" kind of deal.

from that site:

the DIS system utilizes inputs from both the crankshaft position sensor and the cylinder identification sensor...to control ignition timing

The CID signal provides the DIS Module with the information it needs to synchronize the ignition coils in the proper sequence (timing).

the cam sensor (or CID if you like) is used in determining ignition timing