Using a 4-teeth crank wheel?

[Reverant]

Hi guys,

I'm looking at installing an MS-II V3 on my 2002 Mazda Miata. However, one of the problems encountered is the crank wheel and crank angle sensor: VR-type sensor and a 4-teeth crank wheel. The wheel looks like this:

http://www.flyinmiata.com/index.php?dep ... r=07-91000

..minus the adjustable mounting points. From what I can tell, the teeth are NOT evenly spaced (ie 90 degrees apart) but rather their spacing is something like 60 - 120 - 60 - 120 or 70 - 110 - 70 - 110. Can the MS-II work with a configuration like that? I would like to keep the stock timing wheel and sensor for the time time being, as I would like to keep the stock ECU in place (it manages several things like VVT, EGR, VTCS, A/C, alternator...) and use the MS-II for fuel delivery first and spark later on. The current (stock) ignition is wasted spark type, with 2 coils (and integrated ignitors) which might have to be replaced as the ignitors are sensitive and burn up easily.

Many thanks,
Dimitris

[Jim]

If 2 of the points (or Poles) could be ground off it would be perfect .
but then your stock ECM wouldn't work .
You only need 2 pulses per engine revolution for MS .

Do you have to drive it to work every day ? or is it a Hobby Car .

MS can control VVT and AC cut-out no prob. , what is VTCS ?
You don't need or want EGR depending upon local emmisions testing ,
but MS can probably control that too .

You could Drill 2 Evenly spaced holes in your wheel ,
at 90 degrees BTDC ,
(get a machine shop to do it)
then install 2 Bolts with washers and nuts ,
installed with plenty of Locktite Red thread locker ,
then install the VR Sensor of your choice .

You will have to determine VR Sensor mounting first .

Do you have 2 bolts on any thing else on the Crank ? , Front Pulley ?
Could you extend 2 pulley bolts ?

Does the engine have a Cam Position Sensor with 4 poles ?

Does your Engine Block have a hole where you could mount a Dizzy ?
or , did the engine family you have ever come with a Dizzy mounted
on the end of the Camshaft ?

I read something about the V-6 having a 36 minus 1 wheel ,
will it bolt up ?
You could then run Ford EDIS , it's bulletproof and easy to connect to MS .


...................Jim

[Reverant]

Do you have to drive it to work every day ? or is it a Hobby Car.

It's my daily ride, but I can work something out if so required.

MS can control VVT and AC cut-out no prob.

I doubt it can control the Miata's VVT system, which is quite complex. Further analysis is possible, suffice to say that you need a PWM solenoid controller with PID functionality, or at least P and D.

what is VTCS ?

Variable Tumble Control System, a second set of throttle plates inside the intake runners, just before the intake valves. They open and close based on RPM and TPS readings, thereby altering the airflow characteristics to give better low and midrange torque.

You don't need or want EGR depending upon local emmisions testing, but MS can probably control that too .

Yup, could care less about the EGR, too complicated as well, would be neat though.

You could Drill 2 Evenly spaced holes in your wheel ,
at 90 degrees BTDC ,
(get a machine shop to do it)
then install 2 Bolts with washers and nuts ,
installed with plenty of Locktite Red thread locker ,
then install the VR Sensor of your choice .

You will have to determine VR Sensor mounting first .

This propably seems to be the best option: Add a second VR sensor, taking reading from the crank pulley (the timing wheel is behind the crank pulley). This will help me keep the stock ECU, until I can figure out a way to ditch it alltogether.

Does the engine have a Cam Position Sensor with 4 poles ?

Yes, but it is useless as it's mounted on the intake side, where the VVT system advances or retards the camshaft position, thus the signal from CMP sensor is unsuitable.

Dimitris

[Jim]

Sorry I was thinking of Toyotas VVT System ,
which is either on or off at 4500rpm .

You can control VTCS though .
(why does everything have to be an abbreviation)

Actually the Intake Cam Sensor would work OK for fuel only ,
but not for Ignition Timing .

Does it use chain or belt tensioners to move the cam timing ? or
does it move the Cam in relation to the Sprocket ? if it's the later ,
is the wheel mounted to the Sprocket or the Camshaft ?

If the Sprocket doesn't move , and the Sensor is on the Sprocket ,
it doesn't matter if the Cam Moves .

...................Jim

[Reverant]

Sorry I was thinking of Toyotas VVT System ,
which is either on or off at 4500rpm .

No problem, this one is quite a beast as it is continiously variable.

You can control VTCS though .
(why does everything have to be an abbreviation)

Cool.

Actually the Intake Cam Sensor would work OK for fuel only,
but not for Ignition Timing .

Agreed.

Does it use chain or belt tensioners to move the cam timing ?

Neither. It uses the engine's oil. There is an Oil Control Valve (OCV) on the top of the cam cover. The said valve is a solenoid valve. The oil running through the valve pushes an actuator that is mounted on the front of the intake cam gear. The width of the pulse (remember PWM) controls the rate of change (opening/closing) of the valve, while the current running through the valve controls how much the valve will actually open or close.

or does it move the Cam in relation to the Sprocket ? if it's the later, is the wheel mounted to the Sprocket or the Camshaft ?

The wheel is mounted on the camshaft. Why? Remember that the VVT system uses oil pressure (the engine's oil) to push the VVT actuator. Oil pressure will vary with oil temperature, oil viscosity, thus the ECU needs to know: "I told the actuator to advance the opening of the valves 5 degrees, how much has it actually advanced? Oh, only 4 degrees (1 less), OK, in the next loop I'll open up the oil control valve juuust a bit more to compensate." In other words, closed-loop VVT control.

If the Sprocket doesn't move , and the Sensor is on the Sprocket, it doesn't matter if the Cam Moves.

Doh! - See above.