Why can't I just replace the wire?

[Ricochet]

I just read a handful of ecu crush mod threads and was wondering why, instead of crushing a resistor, can't I just solder a new bare wire in its place? If you're going to crush the resistor to eliminate resistance, this seems smarter and cleaner to me.. I have a degree in electronics and am a soldering ninja so I won't mess it up.

[ensteele]

Go for it and let us know how it works. You might take a few pictures so we see how it is done. Good luck.

[rbalach]

Originally Posted by Ricochet

I just read a handful of ecu crush mod threads and was wondering why, instead of crushing a resistor, can't I just solder a new bare wire in its place? If you're going to crush the resistor to eliminate resistance, this seems smarter and cleaner to me.. I have a degree in electronics and am a soldering ninja so I won't mess it up.

Assuming this is right: resistance is crushed ie: removed from the circuit ?

that means there is no connection left between the two points ie: the resistance is infinite between the two point ie: you should not connect a wire between the two points because doing so sends the resistance between the two points to zero.

[svxcess]

Originally Posted by rbalach

Assuming this is right: resistance is crushed ie: removed from the circuit

You are only crushing the barrel portion of the resistor and leaving the wire that ran through it intact, thereby removing the resistance to current flow from the circuit.

The factory TSB is very clear on this. See instruction #4 on the TSB below
http://members.tripod.com/quick_svx/.../42748814.html

"Locate the black noise suppressor.
Wrap the noise suppressor with electrical tape.

4) Holding the ECM upside down or on its side, grasp the black barrel shaped portion of the noise suppressor with needle nose pliers. Slowly squeeze the noise suppressor until the barrel shaped portion is crushed. "DO NOT USE A TWISTING MOTION." Be extra careful not to cut the wire which runs through the center of the suppressor. If the wire is cut or broken the ECM must be replaced.

Holding the ECM upside down, remove the tape from the noise suppressor and lightly shake the ECM to make sure all the crushed particles are out of the circuit board."


If you cut through or somehow broke that wire, it becomes an open circuit with infinite resistance. Leaving the wire intact causes the resistance in this part of the circuit to be zero.

I think what Ricochet is saying is if he soldered a piece of wire across each side of the "resistor" (thereby providing an alternate current path), that current would tend to follow the path of least resistance (the wire) and not the resistor. This doen't seem any easier. Once you crush the resistor, then that's it. You will never have any reason to revert back to the original state. If you happened to accidentally break that wire, then you could solder between them.

I dont know why subaru says if this wire breaks, you have to replace the entire ECM.


.

[thundering02]

Would you trust your local dealer ship with your ecm?

[oab_au]

Originally Posted by Ricochet

I just read a handful of ecu crush mod threads and was wondering why, instead of crushing a resistor, can't I just solder a new bare wire in its place? If you're going to crush the resistor to eliminate resistance, this seems smarter and cleaner to me.. I have a degree in electronics and am a soldering ninja so I won't mess it up.

Hi there, It is not a resistor, it is a ferrite bead that the wire passes through. As you would know, this acts as an inductor that delays the rise time of the signal that that wire carries. Crushing it removes its effect.

Harvey.

[svxcess]

Harvey,

Thanks so much for that clarification. Now it makes perfect sense!

In the past, the noise suppressor (inductor) in the ECM has sometimes been erroneously referred to as the "bead crush" or "resistor crush", because its barrel shape looks somewhat like a resistor, without the color banding.

The tranny resistor also controls the way the tranny performs, but in a different way from the bead crush. Sometimes we interchange these terms without thinking.

So the 92s and 93s had a factory-designed induction system, which was removed by 1994

[oab_au]

Originally Posted by svxcess

Harvey,

Thanks so much for that clarification. Now it makes perfect sense!

In the past, the noise suppressor (inductor) in the ECM has sometimes been erroneously referred to as the "bead crush" or "resistor crush", because its barrel shape looks somewhat like a resistor, without the color banding.

The tranny resistor also controls the way the tranny performs, but in a different way from the bead crush. Sometimes we interchange these terms without thinking.

So the 92s and 93s had a factory-designed induction system, which was removed by 1994

Don't know for sure but it was probably fitted as a noise suppressor, that ended up being a 'action suppressor'. Delayed the action too much, to produce the flat spot.

The tranny resistor is just a dropping resistor, as there are two feeds to the A solenoid, the dropping resistor prevents the two different voltages from from interacting.

Harvey.

[Ricochet]

I don't think any of you understood what I was saying. I want to take out the "inductor" and the wire holding it on, completely off of the circuit board from the solder points. I then was saying why not just replace that entire thing with a plain old bare wire, but I guess it would just be easier to crush the damn thing.

If for some reason my superhuman strength causes the wire to break just from pliers, I'll replace it with a bare wire. Anyways, I got it and will post my own pictures since it's always posted in such a confusing way.. I don't know why people do that.

[svxcess]

I've known a few members that have performed this crush without a problem at all. The inductor part is much more brittle than the wire and will shatter without too much effort.

The key to this is NOT to twist the wire back and forth while trying to crush the bead. It is the twisting motion that fatigues the wire and makes it prone to break. Smooth steady pressure is the key.

[Ricochet]

So this "bead" is a little silver ball on the wire right?

[svxcess]

The noise suppressor is tiny and black -NOT TAN. It looks like an inductor. (It's cylindrical, with what appears to be a ferrite wrap around a metallic core, perhaps 1/4" in diameter, with wires coming from each end).



Near the very end of the right side of the circuit board in this photo (to the right of the tan resistor) you will either see:

1) A vertically-oriented piece of wire connecting two points in the circuit (as in the photo) which means the bead has already been crushed for you, or

2) A wire with a black, barrel shaped piece on it (the bead) which needs to be crushed. LEAVE THE TAN RESISTOR ALONE.

[thundering02]

Deleted....

[kuoh]

I just left it in place and soldered a wire across it. Removing it seemed redundant since this pretty much the same as a short, and I can easily revert back to factory specs if needed.

KuoH

Originally Posted by Ricochet

I don't think any of you understood what I was saying. I want to take out the "inductor" and the wire holding it on, completely off of the circuit board from the solder points. I then was saying why not just replace that entire thing with a plain old bare wire, but I guess it would just be easier to crush the damn thing.