I have a theory about the blinky power light

[Trevor]

Originally Posted by Earthworm

Trevor, I have seen this writeup enough times now that I have just decided to add it to the SVXipedia on http://svx-iw.com in the transmissions section.

Good idea, copyrights no problem.

[Budfreak]

I've tried that and every other way possible to wire this thing DWD1985, But it hasn't seemed to make a difference. I still have a blinky power light on not all, But most start ups. The kit seems to be working as intended though and has the 670 OHM resistor on it and so on. I just ignore it and drop it down in 3rd every now and again to make sure I still have engine braking and all is still working well.

[deputymarshall]

Trevor:

I know I've tried to digest your posts and I think I mostly understand...

With regard specifically to my prior post, I thought, a priori, that when a resistor/switch (read: the smallcar addon) is in series, it doesn't matter whether the addon comes before or after the OEM resistor.

That said, the prior posts in this thread suggested that the connection sequence mattered.

Rather than thinking too much about it, I tried both scenarios and reported back (i.e. no blinking w/o small car; blinking with smallcar irrespective of the order of series wiring).

Now...

Putting aside the wisdom of the small car addon and the tradeoff between valve "wear" from abrupt shifts and band/transmission wear from "slow" shifts, is it your considered opinion that the small car shiftkit cannot be used without "inducing" the blinking power light?

Some seem to suggest that small car shift kits and no blinking lights can happen. Others have not achieved this.

And, I want to say explictly that I understand that blinking lights vs. no blinking lights may have little to do with reality (that is, the actual wear and tear on transmission. or what is actual performance of car). That is, I realize, this is really sort of a "point of order" academic discussion.

Also, for the record, I see little difference between when I use the small car kit and not. For the most part, the improvement in transmission performance seems to have come from addressing the underlying problem with the OEM resistor (and in fact, I've been driving around w/o the small car kit connected but with the new resistor installed in place of OEM).

Best,

-jim D.

[oab_au]

Originally Posted by Trevor

First I must let off steam because I spent endless time, many moons ago, sorting out, what I consider an unnecessary device and what is more, Smallcar should be backing their product with the required information so often called for by their customers.

The dubious object of the system is to open the OEM resistor circuit so as to increase transmission line pressure under certain conditions. The object was to insert a pressure sensitive switch in the resistor circuit for this purpose, i.e. the wire cut and the switch inserted.

In this situation when the switch operates, the diagnostic fault circuitry will find an open circuit and indicate a fault with a blinking light. In order to prevent this, a high value resistor is connected across the switch contacts, so that the circuit is not fully opened by the switch, but a high resistance inserted in series kills effective operation, as would completely opening the circuit.

Take into account the following information which I have posted several times and in particular note reference to the dropping resistor circuit.

DUTY SOLENOID VALVE "A".

This is a pulse width modulated duty solenoid valve, ( Sometimes known as a pulsoid). The device is incorporated in the SVX transmission control system in order to adjust line pressure in the following manner :-

The fluid line is provided with a bleed or bypass via an on/off device, in the form of an electrically operated valve. This solenoid valve is opened and closed repeatedly, in a rhythmical manner by a control current which is turned on and off by the transmission control unit (TCU) at a very fast rate. The valve is a normally closed device, and remains closed in the event of the loss off a control current.

After passing through this modulated solenoid valve, the continually interrupted pressure is in the form of a pulsed flow. When the peaks level off with the troughs, there is a resulting overall steady reduced pressure. The level of this pressure is adjusted by varying the on/off intervals. Most often the length of the on time is adjusted and the number of on/off pulses per second is kept constant. The usual rate is around 50 cycles per second.

The resulting adjusted output pressure is therefore delivered as a rapidly fluctuating stream. The system incorporates an expansion chamber as a smoothing element, which works as a sort of cushion. This device is usually in the form of a cylinder and piston or diaphragm, backed by a coil spring. In the SVX system the component is described as a Pressure Modifier Accumulator. The high pressure peaks in the stream press the piston outwards and become rounded off, while the low pressure troughs are filled in as a result of the piston moving inwards under spring pressure. The end result is a smoother level of pressure, such that controlled devices are not materially affected.

An increase in the volume of fluid controlled, is achieved by transferring the solenoid regulated pressure, to a pressure modifier valve and a regulator valve.

It should be clear that by “chopping” the fluid supply in an adjustable way, pressure control is achieved economically using a simple poppet type solenoid valve, with few mechanical or electrical complications. However the valve remains in a continuos cycling mode, which imposes rather arduous mechanical stresses.

THE DROPPING RESISTOR CIRCUIT.

It will be immediately apparent that a sudden on off cycle tends to cause what could be called a hammering of the valve seat, even though this is largely checked by the viscosity of controlled fluid flow. The dropping resistor introduces a second series of current pulses applied in parallel with the control signal. These shorter pulses are applied during the off cycles and timed to check the travel of the armature as it reaches the closed position, thus reducing both shock and noise. These secondary parallel signals in effect, “round off” the closing period and reduce the closing shock. This arrangement can be made even more sophisticated and configured so as to soften the the opening cycle, as well as the closing of the valve.

It will be appreciated that reducing the resistance in the circuit, or opening the circuit by omitting the dropping resistor, has two outcomes. Firstly the relative electrical off time is increased thus increasing the line pressure and therefore makes shifts more abrupt. Importantly as a second issue, increased shock loads are applied to the valve.

The resistor should measure between 9 and 15 ohms to be within specifications. The usual is about 12 ohms.

It is a documented fact that the line pressure control solenoid is the first to fail due to having by far the most arduous duty to fulfill. Failure is usually mechanical resulting in the valve seat not closing properly and as a result line pressure is markedly reduced. The end results are drastic, especially in respect of transmission friction surfaces. The fault will not necessarily be registered as a fault code, as the armature of the valve can be in the fully closed position with the problem confined to a worn and faulty valve seat. In the event of an electrical fault, which will register, the valve being normally closed, will fail safe and result in maximum line pressure.

There is reason to believe this post to be inaccurate and misleading. Further info can be found in this thread.
http://www.subaru-svx.net/forum/showthread.php?t=35942

Harvey.

[NikFu S.]

I mentioned this after installing mine, but my blinking light was directly related to how soft or firm I set the shifts to be. Hard shifts would make the light blink, soft would not.

[oab_au]

Originally Posted by Trevor

First I must let off steam because I spent endless time, many moons ago, sorting out, what I consider an unnecessary device and what is more, Smallcar should be backing their product with the required information so often called for by their customers.

The dubious object of the system is to open the OEM resistor circuit so as to increase transmission line pressure under certain conditions. The object was to insert a pressure sensitive switch in the resistor circuit for this purpose, i.e. the wire cut and the switch inserted.

In this situation when the switch operates, the diagnostic fault circuitry will find an open circuit and indicate a fault with a blinking light. In order to prevent this, a high value resistor is connected across the switch contacts, so that the circuit is not fully opened by the switch, but a high resistance inserted in series kills effective operation, as would completely opening the circuit.

Take into account the following information which I have posted several times and in particular note reference to the dropping resistor circuit.

DUTY SOLENOID VALVE "A".

This is a pulse width modulated duty solenoid valve, ( Sometimes known as a pulsoid). The device is incorporated in the SVX transmission control system in order to adjust line pressure in the following manner :-

The fluid line is provided with a bleed or bypass via an on/off device, in the form of an electrically operated valve. This solenoid valve is opened and closed repeatedly, in a rhythmical manner by a control current which is turned on and off by the transmission control unit (TCU) at a very fast rate. The valve is a normally closed device, and remains closed in the event of the loss off a control current.

After passing through this modulated solenoid valve, the continually interrupted pressure is in the form of a pulsed flow. When the peaks level off with the troughs, there is a resulting overall steady reduced pressure. The level of this pressure is adjusted by varying the on/off intervals. Most often the length of the on time is adjusted and the number of on/off pulses per second is kept constant. The usual rate is around 50 cycles per second.

The resulting adjusted output pressure is therefore delivered as a rapidly fluctuating stream. The system incorporates an expansion chamber as a smoothing element, which works as a sort of cushion. This device is usually in the form of a cylinder and piston or diaphragm, backed by a coil spring. In the SVX system the component is described as a Pressure Modifier Accumulator. The high pressure peaks in the stream press the piston outwards and become rounded off, while the low pressure troughs are filled in as a result of the piston moving inwards under spring pressure. The end result is a smoother level of pressure, such that controlled devices are not materially affected.

An increase in the volume of fluid controlled, is achieved by transferring the solenoid regulated pressure, to a pressure modifier valve and a regulator valve.

It should be clear that by “chopping” the fluid supply in an adjustable way, pressure control is achieved economically using a simple poppet type solenoid valve, with few mechanical or electrical complications. However the valve remains in a continuos cycling mode, which imposes rather arduous mechanical stresses.

THE DROPPING RESISTOR CIRCUIT.

It will be immediately apparent that a sudden on off cycle tends to cause what could be called a hammering of the valve seat, even though this is largely checked by the viscosity of controlled fluid flow. The dropping resistor introduces a second series of current pulses applied in parallel with the control signal. These shorter pulses are applied during the off cycles and timed to check the travel of the armature as it reaches the closed position, thus reducing both shock and noise. These secondary parallel signals in effect, “round off” the closing period and reduce the closing shock. This arrangement can be made even more sophisticated and configured so as to soften the the opening cycle, as well as the closing of the valve.

It will be appreciated that reducing the resistance in the circuit, or opening the circuit by omitting the dropping resistor, has two outcomes. Firstly the relative electrical off time is increased thus increasing the line pressure and therefore makes shifts more abrupt. Importantly as a second issue, increased shock loads are applied to the valve.

The resistor should measure between 9 and 15 ohms to be within specifications. The usual is about 12 ohms.

It is a documented fact that the line pressure control solenoid is the first to fail due to having by far the most arduous duty to fulfill. Failure is usually mechanical resulting in the valve seat not closing properly and as a result line pressure is markedly reduced. The end results are drastic, especially in respect of transmission friction surfaces. The fault will not necessarily be registered as a fault code, as the armature of the valve can be in the fully closed position with the problem confined to a worn and faulty valve seat. In the event of an electrical fault, which will register, the valve being normally closed, will fail safe and result in maximum line pressure.

There is reason to believe this post to be inaccurate and misleading. Further info can be found in this thread.
http://www.subaru-svx.net/forum/showthread.php?t=35942

Harvey.

[Trevor]

Originally Posted by oab_au

There is reason to believe this post to be inaccurate and misleading. Further info can be found in this thread.
http://www.subaru-svx.net/forum/showthread.php?t=35942

Harvey.

The reason for this post is one of deceit and an effort to defer attention from this thread:-

http://www.subaru-svx.net/forum/show...306#post442306

[Trevor]

Originally Posted by oab_au

There is reason to believe this post to be inaccurate and misleading. Further info can be found in this thread.
http://www.subaru-svx.net/forum/showthread.php?t=35942

Harvey.

Harvey,

The following is an extract from the opening post in the thread that you have suggested by way of a reference.

Please confirm for members, that your advice can be accepted as exactly correct.

Quote ---”When full throttle is used, the solenoid stays as an open drain, and the pressure is held high. As the throttle is closed the Throttle Duty Cycle current, is increased to reduce the solenoids drain on the Pilot pressure that acts on the Regulator Pressure Modifier valve and Line pressure is reduced.”