power mode still/again

[svxistentialist]

We did talk about this a lot before.

I think Spinn 360 has an electrical fault. This is triggering the Power mode, and the speedo antics. It could be a bad earth. Currently I am suffering electrical problems with my car as well. The difference is, my speedo is not getting a signal at all, so no shift out of first.

I sold my JDM car some months ago. For the last two years, in fact since I rebuilt the tranny, I kept it in Power mode all the time. You can do this with the JDM console switch. It seems to work the same as a friend's BMW 530, they call it Sport mode.

The reason I kept it switched on was I felt the natural [or normal] inclination for the standard shift map to IMMEDIATELY go for a higher gear once the car was moving was causing a lot of gear changing at really low revs. I interpreted this as slow slurring changes with low line pressures, and I saw two potential problems with this
1) Increased oil temperatures because of the low rev low line pressure shifts.

2) Increased friction material wear because of the low line pressure and the longer [drawn out in time] shifts.

Both of these problems are interdependent, as you can see.

Put more succinctly, harder shifts = less wear, less heat.

As for economy, I mentioned this before, also a long time ago. I check every tank, brim to brim. Using Power mode all the time meant an increase in consumption of 1 to 2 mpg, or none at all, depending on driving style.

So I rationalised that given this minor increase in the year's fuel consumption, versus the cost of another gearbox rebuild, it was a no brainer and a no contest. So Power. Permanently.

This English car I now have will only do Power mode based on demand as determined by the rapidity of flooring the throttle. I'm not looking forward to it. If anyone can suggest a way to wire the Econ switch to turn on Power instead, that's what I would like to hear.

Joe

[Trevor]

?D?ha]You can see the wiring in the diagram I posted earlier. The signal from speed sensor 2 goes to the TCU and the speedo.

It sounds like you might have a ground fault in the wiring for the TCU.

The TPS wire shorting to ground causes the power mode to come on.
The Speed sensor wire intermittantly shorting to ground due to engine vibration might produce pulses that the speedo would misinterpret as a speed signal.

Trevor, or one of the other electronics experts may have a better theory.[/QUOTE]

The above is good advice and I hope you have this inexpensive fault. But, I would say that unfortunately all now points to a probably faulty TCU.

Best of luck, Trevor.

[Trevor]

Originally Posted by svxistentialist

We did talk about this a lot before.

I think Spinn 360 has an electrical fault. This is triggering the Power mode, and the speedo antics. It could be a bad earth. Currently I am suffering electrical problems with my car as well. The difference is, my speedo is not getting a signal at all, so no shift out of first.

I sold my JDM car some months ago. For the last two years, in fact since I rebuilt the tranny, I kept it in Power mode all the time. You can do this with the JDM console switch. It seems to work the same as a friend's BMW 530, they call it Sport mode.

The reason I kept it switched on was I felt the natural [or normal] inclination for the standard shift map to IMMEDIATELY go for a higher gear once the car was moving was causing a lot of gear changing at really low revs. I interpreted this as slow slurring changes with low line pressures, and I saw two potential problems with this
1) Increased oil temperatures because of the low rev low line pressure shifts.

2) Increased friction material wear because of the low line pressure and the longer [drawn out in time] shifts.

Both of these problems are interdependent, as you can see.

Put more succinctly, harder shifts = less wear, less heat.

As for economy, I mentioned this before, also a long time ago. I check every tank, brim to brim. Using Power mode all the time meant an increase in consumption of 1 to 2 mpg, or none at all, depending on driving style.

So I rationalised that given this minor increase in the year's fuel consumption, versus the cost of another gearbox rebuild, it was a no brainer and a no contest. So Power. Permanently.

This English car I now have will only do Power mode based on demand as determined by the rapidity of flooring the throttle. I'm not looking forward to it. If anyone can suggest a way to wire the Econ switch to turn on Power instead, that's what I would like to hear.

Joe

Both the economy and manual (higher shift point) switches, control by completing circuits to ground. The manual switch completes a circuit between terminal 6 in the TCU 20 pin connector, B66. Wire colour brown and black. The economy switch terminal 4. Wire colour, Light green and Black.

Provided that the same facilities are provided on all TCU units, i.e.all models, you are in business. If you complete this modification, you should add it to the "how to" list.

Best of luck wrestling with the hard to get at TCU. Trevor.

[svxistentialist]

Originally Posted by Trevor

Both the economy and manual (higher shift point) switches, control by completing circuits to ground. The manual switch completes a circuit between terminal 6 in the TCU 20 pin connector, B66. Wire colour brown and black. The economy switch terminal 4. Wire colour, Light green and Black.

Provided that the same facilities are provided on all TCU units, i.e.all models, you are in business. If you complete this modification, you should add it to the "how to" list.

Best of luck wrestling with the hard to get at TCU. Trevor.

Thanks Trev.

I have been at it you know. Got right in under. Got my hand on it. But at my age, I can't see it.

Typical, eh?

Joe

[Trevor]

Originally Posted by svxistentialist

Thanks Trev.

I have been at it you know. Got right in under. Got my hand on it. But at my age, I can't see it.

Typical, eh?

Joe

Greetings Joe,

As long as your tummy is not stopping you from seeing "it", you are OK !!

All the best, Trevor

[spinn360]

I have a tcu coming so if that doesnt fix it then I would guess it would have to be wiring.





I didnt even see the pic of the diagram as I thought it was part of you sig sorry. Now I will look at it.

[svxistentialist]

Originally Posted by Trevor

Greetings Joe,

As long as your tummy is not stopping you from seeing "it", you are OK !!

All the best, Trevor

You are so right Trevor.

Other people got a tummy bug.

I've got a TCU bug.

Joe

[b3lha]

Originally Posted by svxistentialist

This English car I now have will only do Power mode based on demand as determined by the rapidity of flooring the throttle. I'm not looking forward to it. If anyone can suggest a way to wire the Econ switch to turn on Power instead, that's what I would like to hear.

Joe,

The JDM and Euro TCUs are probably the same hardware, but the software is different. Pin 4 signals the TCU to change shift maps. On a Euro TCU, you ground pin 4 to enable Economy mode. On a JDM car, you ground pin 4 to enable Power mode.

There are two ways you can make a power switch on a car with a Euro TCU:

1) Mess with the TPS signal as per the FAQ.
2) Swap in a JDM TCU and then remove the bulb from the Econ light on the dash. This will make your Econ switch into a Power switch. AFAICT the JDM TCU should work fine with the Euro transmission.

Phil.

[svxistentialist]

Originally Posted by b3lha

Joe,

The JDM and Euro TCUs are probably the same hardware, but the software is different. Pin 4 signals the TCU to change shift maps. On a Euro TCU, you ground pin 4 to enable Economy mode. On a JDM car, you ground pin 4 to enable Power mode.

There are two ways you can make a power switch on a car with a Euro TCU:

1) Mess with the TPS signal as per the FAQ.
2) Swap in a JDM TCU and then remove the bulb from the Econ light on the dash. This will make your Econ switch into a Power switch. AFAICT the JDM TCU should work fine with the Euro transmission.

Phil.

Thanks Phil

As I have a JDM TCU sitting here, I might just do that to see if it works like you say.

Two questions occur; in the JDM car, we are accustomed to thinking the ECU has software that "restricts" the top speed to 180 kms/h. Would it be safe to presume the TCU, which handles the speed signal before the speedo, has no role in this? In other words, using a European ECU with a Japanese TCU should not impose the Japanese speed limit to the arrangement?

The other question is similar; the JDM ECU is tuned to use top grade petrol, while the Eu models are tuned to handle our rubbish. Would the JDM TCU be tuned in any way to suit the better grade petrol they enjoy? I presume not?

This is interesting all right. As I currently have the underdash area eviscerated to access the bloody TCU, I WILL stick in the Japanese one, just to see what lights up, what doesn't. What have I to lose except more skin off my knuckles?

[svxistentialist]

Originally Posted by b3lha

Joe,

The JDM and Euro TCUs are probably the same hardware, but the software is different. Pin 4 signals the TCU to change shift maps. On a Euro TCU, you ground pin 4 to enable Economy mode. On a JDM car, you ground pin 4 to enable Power mode.

There are two ways you can make a power switch on a car with a Euro TCU:

1) Mess with the TPS signal as per the FAQ.
2) Swap in a JDM TCU and then remove the bulb from the Econ light on the dash. This will make your Econ switch into a Power switch. AFAICT the JDM TCU should work fine with the Euro transmission.

Phil.

Phil

This Euro Economy mode has me flummoxed. I've always felt that the software has only two shift maps. One would be Power, which moves the change up points higher in the rev range, and also lets the box kick down more easily. I'm presuming the latter is controlled by reading the speed of voltage change at the TPS, and "allowing" kick-down to happen for gentler shoves on the gas.

The other mode would be Normal or Standard, the one which changes to higher gears way too fast, and clings on to them until you wallop the carpet with the gas pedal.

So can anyone tell me what does Econ mode do, or what is it? Can they possibly make it any slower, or any less responsive, than Normal mode?

Now, the purpose of the Manu button, that makes sense, and I can understand it. It's designed to get the car out of slippery or mucky conditions. It locks out first, and it optimises the highest torque to the wheels, at whichever gear gives lowest revs, to prevent wheelspin.

Could it be that the Econ mode we have in European cars is actually a variant of Manu, possibly with 1st gear allowed a look in?

And does this mean that there are actually three shift maps, Power, Normal and Manu/Econ?? Answers on a postcard please......


Joe

[b3lha]

Originally Posted by svxistentialist

Two questions occur; in the JDM car, we are accustomed to thinking the ECU has software that "restricts" the top speed to 180 kms/h. Would it be safe to presume the TCU, which handles the speed signal before the speedo, has no role in this? In other words, using a European ECU with a Japanese TCU should not impose the Japanese speed limit to the arrangement?

The speed limiter is in the ECU, I have proved this by bypassing it on 4 JDM SVXes. Read this thread for information about how the speed signals differ between JDM and Euro/Aussie cars. Harvey, JJ, Tony and I figured it all out: http://www.subaru-svx.net/forum/showthread.php?t=31506

The other question is similar; the JDM ECU is tuned to use top grade petrol, while the Eu models are tuned to handle our rubbish. Would the JDM TCU be tuned in any way to suit the better grade petrol they enjoy? I presume not?

I've noticed that my cars run MUCH better on 98 octane than 95, so the ECU may have some tuning for higher octane petrol. The TCU wouldn't care about that. It just has to measure a few input signals, run a little algorithm and set the output signals to select the correct gear.

[spinn360]

Sorry to interupt. J/K

So I am not getting my tcu until at least the 21st So................ I jacked up the car and am looking under it and around in the engine bay to see if any wires are burnt, broken, exposed, or what not. I was thinking possibly the tranny problems and the o2 sensors might be related, but I dont know if there is any area where they might come in contact with eachother.


I have to wait for the tranny to cool down though cuz I tried to reach up in there after about an hour after I shut it down and the axles are still hot. SO twiddle de dum here I go back out again.

[b3lha]

Originally Posted by spinn360

Sorry to interupt. J/K

Hey, we're just keeping the thread warm for you

Originally Posted by spinn360

So I am not getting my tcu until at least the 21st So................ I jacked up the car and am looking under it and around in the engine bay to see if any wires are burnt, broken, exposed, or what not. I was thinking possibly the tranny problems and the o2 sensors might be related, but I dont know if there is any area where they might come in contact with eachother.

Why do you suspect the o2 sensors would be causing the transmission problem?

[svxistentialist]

Hey, Spinn

Like Phil says, we're not hijacking your thread, we're just joyriding it for a bit!

More seriously, regards your original problem, I'm not sure you are looking for a solution in the right place.

I'm no electronics expert, I have not sorted my own problem yet, but I WILL.

I think you should be looking harder at the TPS for a solution. Your TPS itself may be faulty, or you may have a bad connection between the TPS and whichever connector block connects it to the ECU and TCU.

Here's the reason I say this; your TCU decides to put on power mode, based on a few parameters, such as road speed and so on. You will have noticed it is much easier to get Power on when going slowly, it's programmed that way. Now, aside from road speed, the one thing the TCU takes into account is the RATE, how fast, you floor the throttle. It interprets this call for power based on the rate of change of voltage shown by the TPS, from zero to 5 volts, or whatever the max is, I've forgotten.

Two things can be wrong with the TPS. It can be set wrong, so the TCU and ECU don't see the voltage they expect at tickover, say, and this creates running problems.

The other thing is closer to your problem. If the TPS is internally damaged through wear and tear, and there is a gap in the wiring that the sweeper crosses, this will give momentary zero readings to the outputs, and "confuse " the computers. Put another way, unless the TPS is good internally, the computers will not see a smooth rise in voltage with throttle depression, and will give erratic behaviour.

This is one way it could malfunction, and give your symptoms. Another way, causing the same problems, would be a poor connection between the TPS and the ECU or TCU. In your case, because the engine is not showing any erratic behaviour[that you have mentioned], but the TCU is activating Power mode for no reason, I strongly suspect you have a bad wiring connection between the TPS and the TCU.

Think about it. If for instance, you are stopped at the lights, and vibration causes the TPS signal to suddenly connect, and shows 3v to the TCU. The TCU sees an instant rise from 0v to 3v, and performs its function, switches in Power mode.

I could be totally wrong about the above, it is just my opinion based on what you describe. It could be caused by a bad earth somewhere which is giving an intermittent signal to the TCU, and causing the same symptoms.

But that is where I would start troubleshooting for your problem.

Best of luck with it man, I know you have had more than your fair share of problems.


Joe

[spinn360]

svxistentialist I have two TPS's one I opened up and cleaned both cause the tcu to put the tranny in power mode. So it has to be either the wire, or the part you didnt mention, the TCU itself. I am getting a used TCU soon. I am going to replace this and if the symptoms percist I am going to re-wire the wire that goes from the tcu to the tps. I thought the o2 sensors wiring and the wiring from the tps might run along with eachother some where. And that possibly something rubbed or somehow removed the plastic over the wires exposing them to eachother, causing the car to malfunction in each place that the wires corrosponded with. Since the o2 Sensors came on at the same time the power mode started happening, that is why I thought the two were connected.