ECU mods and Engine torque control

[TomsSVX]

its not left open. It is merely "OFF" rather than being switched on when needed. People think it works the other way and needs to be switched "off" by grounding the pin. Thats my experience with trying this.

Tom

[Dessertrunner]

Guys right now I can't get mine to stall or miss behave, my question is if I get the Subaru anyliser and plug it in when I am next having problems it should show me if the fuel is cut because it shows the duty time on the injectors. Has any one tried this or do you think it is a waste of time.
Tony

[Trevor]

Originally Posted by TomsSVX

its not left open. It is merely "OFF" rather than being switched on when needed. People think it works the other way and needs to be switched "off" by grounding the pin. Thats my experience with trying this.

Tom

Tom,

I am aware of what you are saying. What I am pointing out is the danger inherent if an input remains with no connection, when not used and idle, i.e. is left open. This represents an anomaly which you can not afford to have existing, in view of your obscure problems.

When talking things electrical, the words "off" and "on" are best not used, because they can be ambiguous/confusing. Energised not energised in respect of a circuit or device; closed open in respect of a circuit, switch or contacts; present or not present in respect of inductance, capacity, voltage, current etc.

If an input connection/pin is not used, the associated input circuit is open, and can receive an induced electrical signal without there being actual contact. When connected to a sensor the input is not open, as there will always be some load present, which in affect closes the circuit. This will constitute both resistance and capacity.

Note that shielded input leads are used as a means of shielding any loop which could be open to an induced input. In effect the input is not open, even though the sensing device is not conducting significant current.

I am saying that when the input circuit is idle, it should not be left open. It should be closed, by means of a relatively high resistance, and better still in addition, a small of amount of capacitance. Otherwise there could be extraneous affects relative to any operative problem.

Be sure I am not presenting this as definitive, but rather as something which in the circumstances must be taken into account.

End of my story, Trevor.

[Trevor]

Originally Posted by Dessertrunner

Guys right now I can't get mine to stall or miss behave, my question is if I get the Subaru anyliser and plug it in when I am next having problems it should show me if the fuel is cut because it shows the duty time on the injectors. Has any one tried this or do you think it is a waste of time.
Tony

Tony,

This would be very worthwhile, as it would positively confirm the exact method used in order to control torque. Without this certainty, surely all is darkness.

Cheers, Trevor.

[Dessertrunner]

I have a question to help me work through the problem. Does the stall occur when NOT BRAKING. As far as I am concerned I don't think my engine has died when not under brakes or recently applied the brakes. May be the key is the cars brakes. The reason I ask is that in the cold today I had a miss and the engine was down to 500 rpm but did not stall.
The logic follows that some action we take tells the computer to cut fuel. What is it? Does the ECU see the Brakes when applied?

[Speedklix]

I also do not jump it. I had wired it per whatever I had read at the time, I think it was huck's directions. The car didn't like to drive and threw a CEL, until I cut the wire.

Is it being implied that I could be harming something by doing this... perhaps it could give me some light to my current issue. Which looks like a failed maf. Side note.. I also found no need to trick the gear to release the key from the ignition... or I was too tired to remember splicing it

[Nomake Wan]

Interesting... though I think the whole 5MT Stall should have its own topic. This topic began with addressing ATs, and believe it or not some of us still have ATs in our cars. So the torque control thing would be useful for me to figure out as something I could do to squeeze a little bit more power out of the drivetrain.

Also, I can't talk about the ECU much... but I did read a lot about the TCU. According to what I read, the TCU does look for ABS signals when sending information to the ECU. But since you guys are talking about MT cars, I don't see how brakes could be affecting what's going on. From what I know so far of the ECU, it does not receive signals from the ABS. Only the TCU cares about what the brakes are doing.

Back onto the real topic... from what I think I'm reading in Trevor's posts about the original topic (as it is all professional electronic speak which I am not fluent with), if we wish to tinker with the torque control, we should disconnect the torque control wire between the ECU and TCU, then add a resistor and capacitor to the ECU side of the wire, then ground that new circuit? Is this correct? From what I gathered, you warn that leaving the wire off and causing the voltage to float by itself is not good.

Hopefully I am interpreting correctly.

[TomsSVX]

braking involves 2 things and could be of either.

Using the brake pedal to slow down

Using the engine to slow down.

The auto uses the engine to slow down. When you are slowing down with either the clutch depressed or the trans in neutral the engine is not braking as the ECU is expecting. It still cuts timing and it still cuts fuel like it would if there was still a connection to the driveline. SO, until we can change the maps to adjust to this difference, it will stall

Tom

[huck369]

Originally Posted by TomsSVX

braking involves 2 things and could be of either.

Using the brake pedal to slow down

Using the engine to slow down.

The auto uses the engine to slow down. When you are slowing down with either the clutch depressed or the trans in neutral the engine is not braking as the ECU is expecting. It still cuts timing and it still cuts fuel like it would if there was still a connection to the driveline. SO, until we can change the maps to adjust to this difference, it will stall

Tom

Not if you wire up a clutch position switch to read "Nuetral" when the clutch is depressed....as then the ECU thinks it's in nuetral.....never had stalling on either of my 5 speeds wired this way.

[crazyhorse]

Slick solution Huck
This also tells the ECU it's "safe" to start the car.

[Dessertrunner]

I the car would start easier as well as the ECu is set for a start.

[Trevor]

Originally Posted by Nomake Wan

Back onto the real topic... from what I think I'm reading in Trevor's posts about the original topic (as it is all professional electronic speak which I am not fluent with), if we wish to tinker with the torque control, we should disconnect the torque control wire between the ECU and TCU, then add a resistor and capacitor to the ECU side of the wire, then ground that new circuit? Is this correct? From what I gathered, you warn that leaving the wire off and causing the voltage to float by itself is not good.

Hopefully I am interpreting correctly.

Nomake you have blown a breath of fresh into a thread which is now a spiders web.

Yes Nomake, you are basically correct.

However the added components would be best, added at the ECU connector, rather than at the end of any wire remaining disconnected from the TCU. Also to be exact, it is the input which would be floating if left disconnected, and therefore open to receive any "floating" inductive voltage.

Not to worry, you have explained everything as near as damn it.

Special thanks, Trevor.

[TomsSVX]

trevor, had it beaten into my head by someone MUCH better with electronics than I. I understand what is going on now. Yet still do not have a good solution

Tom

[Nomake Wan]

Originally Posted by Trevor

Also to be exact, it is the input which would be floating if left disconnected, and therefore open to receive any "floating" inductive voltage.

Just have to ask... you say to add it "at the connector," but to do so would require a wire be placed into the particular pin on the connector anyway... so wouldn't that mean that the circuit to be added would in fact rely on a wire going into the ECU connector at that specific pin?

I had to do that with the "Power Mode" mod, splicing a wire into pin 4 of the TCU and grounding it. I would assume that this modification we are speaking of would be damn near similar, with the addition of a small circuit of resistor and capacitor.

On that note, Trevor, do you have a suggestion as to circuit specifications? That is, exact specifications for a resistor and capacitor to be added. With my new living conditions I now have an easily-accessible electronics store, so I would be willing to take some risks in the name of progress.