ok i know there have been lots of posts relating to this but i would like to geta definative answer here. i have a engine from a unknow source ( supposedly jdm but what ever) im pretty sure its a s4 13bt though. the pully and front hub are both from my old s4 t2 engine. we have had some real problems getting this car running on a E8 haltech. im almost postive this is a timing issue. we have used a timing light and lined it up perfectly only to find the car idles best when the timing is about a tooth advanced. so we are assuming the pully is not in the correct position. how do i time this car without trusting the pully or sound of the car.



i have heard of some thing dealing with looking at though the top plug hole and some thing with the keyway on the eshaft in the front.

Here is the procedure I used:



1. Remove both rear rotor spark plugs.

2. Rotate the crank until you can see an apex seal (tip of the rotor) in the trailing spark hole. The trailing plug hole is restricted, making the seal somewhat difficult to see. Use a flexible light and a mirror. When the seal is seen, mark the crank.

3. Rotate the crank until you see the same apex seal in the leading spark plug hole. This plug hole is not restricted, which makes it easy to see the seal. Mark the crank.

4. Halfway between your two marks is TDC for the front rotor (#1) rotor.



ok so assuming i go do this i have TDC marked. i line the TDC mark up with the CAS and stab it again making sure it does not move? or do i make another mark 5 deg after that and line it up to that?



because i am running a E8 what setting am i going to have to change.



and as long as im asking more questions what EXACTLY does the tooth offset and trigger angle effect on these motors.



the total teeth should be set to how ever many teeth the cas has and the tigger type should be multi tooth right?

its on TDC when the rotor face is flat up against the spark plugs. i forget if the s4's have a keyed hub, the s5's only go on one way.



so at tdc, the rotor face is flat up against the plugs, the key way on the eshaft is at 9 oclock, when you are in front of the engine.





the cas generates 2 signals. it has a "home" signal, there are 2 teeth, so it gets a pulse every 360 degrees of crank rotation (cas rotates at half engine speed)



the other signal (mazda calls em G and NE, i dont remember which is which), is a plused signal, i think its got 32 or 36 teeth, so the ecu gets a signal every few degrees.



the ecu not only computes, rpm, but ignition timing and injector timing, so it needs to know where the engine is in its cycle.



so the the tooth offset is telling the haltech how many teeth go between the 2 signals (i think).

and the trigger angle basically is the number of degrees between i think the home tooth and tdc.



the trigger angle and your maximum ignition advance are the same number! you want it over 40

yeah s4's only go on one way but i have heard that they are all the same and they are all different so i really dont trust either right now.



but if you are saying TDC is when the rotor is flat against the plug face isnt that the exact opposite of what that article is saying?

bdc, is when the apex seal is between the 2 plug holes