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  #16  
Old 10-05-2004, 06:31 PM
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Makes total sense. Why have more power going to the tranny that isn't going to be put to the ground properly, through the slipping bands in the tranny. Could I just install a multiple throw switch that simaltaneously disables solenoid A for full line pressures shifts and at the same time eliminates the torque control function, for use when dragging/racing?

The other question was as to when using a manual tranny when the TCU is removed, is the torque control always active since the ECU now recieves a 0 volt signal at that terminal? In my friends 5spd SVX, power seems to fall off fast after 3000rpms.

Also, is there a way to manually control the Air Resonance valve in the intake manifold? Is this unit at all disabled with the replacement of a manual tranny? It too could be the cause for the loss in power on the higher end if it doesn't open properly.

Greg
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  #17  
Old 10-05-2004, 07:39 PM
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[QUOTE]Originally posted by svxboy
[B]Makes total sense. Why have more power going to the tranny that isn't going to be put to the ground properly, through the slipping bands in the tranny. Could I just install a multiple throw switch that simaltaneously disables solenoid A for full line pressures shifts and at the same time eliminates the torque control function, for use when dragging/racing?

___________________________________________
You could Greg, be a bit crude, It would be better to use two Small cars vacuum switchs, one on the TCU line to the A solenoid, and one on the torque control line. That way the TCU unit could be adjusted to work at say 20% throttle and the other on the Torque control line, could be adjusted to switch at full throttle. At light throttle openings, it would be normal, at higher throttle openings it would firm up the shift, and at full throttle, firm, full torque shifts.
__________________________________________


The other question was as to when using a manual tranny when the TCU is removed, is the torque control always active since the ECU now recieves a 0 volt signal at that terminal? In my friends 5spd SVX, power seems to fall off fast after 3000rpms.

___________________________________________
With the TCU removed the Torque control line is pulled up to 5 volts by the ECU, it's the TCU that pulls it down to 0 volts to reduce torque. If it is removed it should stay up at 5 volte all the time. Does your friends SVX have the exhaust resonator still fitted, won't make top end power without it.
__________________________________________

Also, is there a way to manually control the Air Resonance valve in the intake manifold? Is this unit at all disabled with the replacement of a manual tranny? It too could be the cause for the loss in power on the higher end if it doesn't open properly.
____________________________________________
Anything is possibable, but the way it is set up is to open at the right change over point, changing it to some other rpm won't help. No the manual replacement won't affect the operation. If the valve does not open it will stay in the Inerta mode, fall flat over 4000rpm. You could check if it is working by useing a light to see the arm under the manifold, that works the valve, raise the rpm to about 4500/5000, the arm should move.


Harvey.
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  #18  
Old 10-11-2007, 09:26 PM
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Bizzump!

May as well bump this up from the grave since it is all the talk and rave right now.
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  #19  
Old 10-11-2007, 09:36 PM
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How the heck did you find this?






Lol.
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  #20  
Old 10-11-2007, 10:06 PM
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don't bother... i have tried only to find the car completely falls on its face when jumping the wires (giving it a 5v source). More or less it operates without any torque control with 0v signal and and activates it with a 5v signal...

Tom
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  #21  
Old 10-11-2007, 10:40 PM
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Tom,

Not surprised it did not work, considering the source of the info.

To pick your brain/knowledge --- In respect of the SVX, is torque induced via the interruption of fuel or ignition?

I have always understood that some, but not all cylinders, are deprived of ignition for the short periods involved. This would be plausible as control would be practically instantaneous, as opposed to a probable slight inherent delay.

Please, can someone confirm the exact mode of operation. Please, no opinions, only exact evidence, e.g. pointers towards verifiable published statements, from an absolutely reliable source exhibiting authority.
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  #22  
Old 10-11-2007, 10:52 PM
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cannot verify but my suspicion is that it drops all timing advance

Tom
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  #23  
Old 10-12-2007, 05:01 AM
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Quote:
Originally Posted by TomsSVX View Post
cannot verify but my suspicion is that it drops all timing advance

Tom
I can verify that fuel is reduced or eliminated between shifts based on my dyno runs I did from 1st to 3rd gear. The air/fuel ratio would go off the chart between 1st - 2nd gear. This is not the case with any of my other cars, Subaru or not. Of course this could be an isolated event so I can not generalize (speaking about the air/fuel ratio going way lean).
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  #24  
Old 10-15-2007, 06:42 AM
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Does any ones car stall when the speed is above 20mph. Eg if you quickly clutch in and lift your foot off the trottle does the engine die. If you hit the breaks does that effect if the engine shuts down. When the pins on the ECU are left floating for example not connected to either +5v or ground they could drift between the two. Mine stalls some time for a couple of days then never for two weeks or more. Its a pain and we need to sort it out. If we can all run trials we should be able to figure the event or sequance that causes the engine to shut down.
Tony
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  #25  
Old 10-15-2007, 06:47 AM
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thats the infamous 5mt stall. It is a fuel cut. responsible when the car is moving but the transmission is not engine braking. Thus the engine dies... I am working in finding a 100% solution.

Tom
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  #26  
Old 10-15-2007, 03:50 PM
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I think they are related, for example the ECU looks to see if the engine is in P & N, I would assume (might be wrong) that if it sees this condiation it sets up a starting engine map condiation. Also you would think that ECU would not allow full power under this condiation.
We all need to find out what infomation the ECU is getting that may effect is management under this condiation and then I might be able to put a scope on the imput wires to see if anything goes grazy just before the engine dies. Is your fix manchinal or electronic Tom.
Tony
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1995 - SVX 700,000 K Mine, DMS Struts to lift car 2in. Tyres Wrangler Silent Armor 235/70R16, PBR Radiator. 6 speed with DCCD and R180 rer diff, Heavy duty top strut mounts front and rear. Speedo correction box fitted. New stero (gave up on the old one). Back seat removed and 2 spare tyres fitted for desert driving. ECUTune SC sitting in the box for the next SVX.
1992 - SVX 255 K Wife (Want to stay Married so not allowed to fit SC)
1992 - SVX Pearl with black roof race car roll cauge etc ready to race. Ex Tasman Targa car.
1995 - SVX Green low k mint condiation.
1995 - SVX Rally car, ex Matts car. Now to be used on track.
1992 - SVX red & Black being converted to Mid Engine.
1995 - SVX Red 143,000 bit rough.
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  #27  
Old 10-15-2007, 04:18 PM
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no, it will require rewriting the code in the ECU if it is even possible. A fuel cut cannot be stopped by means of a mechnical modification. I have tried numerous ways of wiring the circuit and none seem to work better than the other. I am at a loss until I can tap into the ECU myself and do some testing

Tom
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  #28  
Old 10-15-2007, 06:53 PM
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Quote:
Originally Posted by Dessertrunner View Post
Does any ones car stall when the speed is above 20mph. Eg if you quickly clutch in and lift your foot off the trottle does the engine die. If you hit the breaks does that effect if the engine shuts down. When the pins on the ECU are left floating for example not connected to either +5v or ground they could drift between the two. Mine stalls some time for a couple of days then never for two weeks or more. Its a pain and we need to sort it out. If we can all run trials we should be able to figure the event or sequance that causes the engine to shut down.
Tony
Leaving an input floating is bad news, in that if the input has a relatively high impedance, the open circuit could induce extraneous noise. This would tie in with the sporadic nature of the problem.

As it would appear that the pin can not be grounded, a small capacitor of say 0.1 mfd connected pin to ground may provide a solution. It is possible that a capacitor as it charges at turn on, could close the input circuit for an instant, but the value suggested should not cause this problem.

As an alternative, a resistor of a value largely exceeding that which would trigger an input, could be tried.
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Last edited by Trevor; 10-15-2007 at 07:22 PM.
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  #29  
Old 10-15-2007, 07:49 PM
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Quote:
Originally Posted by Trevor View Post
Leaving an input floating is bad news, in that if the input has a relatively high impedance, the open circuit could induce extraneous noise. This would tie in with the sporadic nature of the problem.

As it would appear that the pin can not be grounded, a small capacitor of say 0.1 mfd connected pin to ground may provide a solution. It is possible that a capacitor as it charges at turn on, could close the input circuit for an instant, but the value suggested should not cause this problem.

As an alternative, a resistor of a value largely exceeding that which would trigger an input, could be tried.
Edit: Nevermind I re-read it and found it... I don't think that is the issue here. As this should be left alone (torque controll) and we should be looking at a way to keep the engine management from cutting the fuel when the car is rolling but no accelerator is applied in a neutral state. I have noticed ont eh wideband that my idle will bounce back from dead lean once the car comes to a complete stop. This is an indicator to me that the ECU is trying to engine brake. Jumping the neutral pin should take this issue away for anyone else but right now it is not working for me

Tom

Last edited by TomsSVX; 10-15-2007 at 07:53 PM.
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  #30  
Old 10-15-2007, 08:32 PM
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Quote:
Originally Posted by TomsSVX View Post
Edit: Nevermind I re-read it and found it... I don't think that is the issue here. As this should be left alone (torque controll) and we should be looking at a way to keep the engine management from cutting the fuel when the car is rolling but no accelerator is applied in a neutral state. I have noticed ont eh wideband that my idle will bounce back from dead lean once the car comes to a complete stop. This is an indicator to me that the ECU is trying to engine brake. Jumping the neutral pin should take this issue away for anyone else but right now it is not working for me

Tom
This thread is a convoluted mess.

My suggestion directly relates the post (28) originated by Tony and which I quoted within . Also post 24 is directly applicable.

Whatever, no input should be left open as this could result in all sorts of problems.
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