I Feel . . . Violated. (Long) - Page 2

#16 03-01-2002, 02:12 PM

1994subarusvx. are you using oem replacement axles?

SHISVX · #17 03-01-2002, 02:14 PM

Glad you finially got your car back. all the luck in the world to you!

Kelli

Beav · #18 03-01-2002, 03:29 PM

How about they might have replaced the tranfer clutch discs while they were in there? Or something similar. Try doing some figure eights, tight but not necessarily fast, in an empty parking lot and see if that helps. A few in each direction should do the trick, if that's indeed the problem.

I understand the hammer blows, I don't like doing it in front of most customers because it can be unnerving to them. Then there are 'certain' customers...

I forgot you mentioning the end play situ. Something's going on, wrong/missing/misplaced thrust washer, internal leak, etc. Funny thing is that 'soft' shifts are hard on transmissions - the slippage needed to accomplish a soft shift wears the friction faster. Now you know why certain tranny shops have better luck with their rebuilds (longevity) especially when they talk their customers into a 'performance' shift...

Beav

svxter · #19 03-01-2002, 04:16 PM

So you wouldn't think the resistor mod does any harm?

Beav · #20 03-01-2002, 08:46 PM

Quote:

Originally posted by svxter
So you wouldn't think the resistor mod does any harm?

I prefer to leave things as they are engineered unless there's a definite reason not to do so. There are usually several different ways to accomplish the same task, some have side-effects, some don't. The best people to ask would be respected tranny rebuilders and trusted friends that have been long-time guinea pigs.

Beav

svx_commuter · #21 03-02-2002, 11:58 AM

Awhile ago I measured the voltage across the line pressure solenoid and it was out of spec. To bring it back I added another dropping resistor in series. So now the car has two dropping resistors in series. A check of the line pressure readings showed them to be right on the money. This has been working fine for about six months now.

Beav · #22 03-02-2002, 02:21 PM

Quote:

Originally posted by svx_commuter
Awhile ago I measured the voltage across the line pressure solenoid and it was out of spec. To bring it back I added another dropping resistor in series. So now the car has two dropping resistors in series. A check of the line pressure readings showed them to be right on the money. This has been working fine for about six months now.

Now you see why the engine computer is a 'learning' computer! As electronics age (hell, anything for that matter, look at us

), their parameters change. The learning computer operates against a set of values and expects certain parameters to be met. When those parameters fall out of range the computer adjusts its expected values in order to obtain the results it wants. That's why I've always said it's not big voodoo when you disconnect your battery. The car really isn't learning anything about the driver, it's just adjusting itself in order to fall into the expected parameters.

Unfortunately the TCU isn't a learning computer. If it was and it had a line pressure sensor it would have adjusted its program and the duty cycle in order to obtain the pressure it expected under certain conditions.

What I find interesting is that the resistance decreased? Normally age and heat increases resistance. Maybe the available voltage is higher than the engineers expected, have you done the alternator cable upgrade? Hmmm.....

Beav

svx_commuter · #23 03-03-2002, 08:25 AM

Quote:

Originally posted by Beav

What I find interesting is that the resistance decreased? Normally age and heat increases resistance. Maybe the available voltage is higher than the engineers expected, have you done the alternator cable upgrade? Hmmm.....

Beav

Hi Beav,

I have not done the alternator upgrade. What I found puzzling when I was checking this out is that the voltage at the TCU was high for some reason. Anyway, This modification just raises the line pressure some and the TCU still does the adjusting in proportion to the TPS and the power light doesn't come on. An easy mode that doesn't mess anything up.

Beav · #24 03-03-2002, 01:54 PM

That's what I was getting at - the higher voltage or lower resistance and how/why it changed. I don't see anything wrong with what you did, I was just curious about the direction of change. Alternator output voltage high - over 14.2vdc?

Beav

svx_commuter · #25 03-03-2002, 06:47 PM

Quote:

Originally posted by Beav
That's what I was getting at - the higher voltage or lower resistance and how/why it changed. I don't see anything wrong with what you did, I was just curious about the direction of change. Alternator output voltage high - over 14.2vdc?

Beav

Okay back to the notes. Between (B68) No 8 to 10 the voltage spec is 1.5 to 3.0 when the throttle is closed. My car had 2.9 volts with key on, engine off and 3.3 with engine running. Adding in the 2nd resistor made it 1.8 volts key on engine off and 1.9 volts with engine running. Still in the range of 1.5 to 3.0 volts. As I remember the voltage was around 12.4 volts at the TCU. Which I though was odd since it was supposed to be low. You know the alternator wiring mod not being done on my car.

The resistance across solenoid A is spec'ed at 1.5 to 4.5 ohms. That is a hugh spread

Mine measured 4.7 ohms. Take that into account with specified voltage drop 1.5 to 3.0 and dropping resistor spec of 9 to 15 ohms and I think there is a big spread on what one gets for line pressure at idle and how it varies as the throttle is depressed. Fully depressed throttle yields .5 volts (that is 1/2 V). The opening of the solenoid "A" is proportional to the voltage. So it can go from 1.5 to .5 or 3.0 to .5 and that is a 100% change in volatge at idle.

Beav · #26 03-03-2002, 09:40 PM

Now to me it would seem a lot easier and more reliable to include a line pressure sensor and allow the TCU to 'learn' new values. Then again I'm not an engineer or programmer.

Maybe you know something that I'm missing, but a 'duty cycle' valve, to me anyway, means that it regulates pressure by frequency of cycles. Being a solenoid it's either on or off. Is it that you're seeing a voltage change as an indication of cycling rate changes? I guess this is all moot as your problems are solved, I just found it interesting.

Now I can see why you were interested in checking your TPS. I kinda came in at the end of it and assumed you were in it for an engine problem.

Beav

vkykam · #27 03-04-2002, 10:01 AM

SVX_Commuter,

Are you sure it's spec'd at 1.5 to 4.5 ohms? I remember someone mentioning 6 to 9 ohms, and that's what I followed when I repaired my solenoid A.

From what you have said, is it safe to assume that the lower the ohms, the higher the line pressure?

I think I have mine at about 10 ohms. I didn't have a transmission problem last winter, but this winter when my tranny's cold, it's VERY slow to engage 3rd gear. It drops to the correct rev when it disengages from 2nd and prepares to shift into 3rd, but just kinda hovers there for a second or so before it shifts into 3rd. I'm wondering whether I can raise the line pressure a bit to see if it helps, but without disconnecting the solenoid A, since I can't stand what the tranny does coasting in 3rd gear either when I disconnect it.

Any input is appreciated.

VK

Quote:

Originally posted by svx_commuter

Okay back to the notes. Between (B68) No 8 to 10 the voltage spec is 1.5 to 3.0 when the throttle is closed. My car had 2.9 volts with key on, engine off and 3.3 with engine running. Adding in the 2nd resistor made it 1.8 volts key on engine off and 1.9 volts with engine running. Still in the range of 1.5 to 3.0 volts. As I remember the voltage was around 12.4 volts at the TCU. Which I though was odd since it was supposed to be low. You know the alternator wiring mod not being done on my car.

The resistance across solenoid A is spec'ed at 1.5 to 4.5 ohms. That is a hugh spread Mine measured 4.7 ohms. Take that into account with specified voltage drop 1.5 to 3.0 and dropping resistor spec of 9 to 15 ohms and I think there is a big spread on what one gets for line pressure at idle and how it varies as the throttle is depressed. Fully depressed throttle yields .5 volts (that is 1/2 V). The opening of the solenoid "A" is proportional to the voltage. So it can go from 1.5 to .5 or 3.0 to .5 and that is a 100% change in volatge at idle.

1994SubaruSVX · #28 03-04-2002, 01:29 PM

this last time i purchased them locally and they are not oem. if these go out i will go ahead and spend the $250ea. for oem. even if i have to replace them every year i dont care because it will only amount to $500 buck a year. big deal.

#29 03-04-2002, 02:18 PM

Thanks, I didn't know if aftermarket was available. Bill Z

#30 03-04-2002, 06:24 PM

Quote:

Originally posted by svx_commuter

You know the alternator wiring mod not being done on my car.

Hate to sound stupid...but what is the alternator wiring mod? Also, one question. My car is having trouble starting...it turns over, but the engine does not catch. Usually takes me 2-3 times trying this to get it started, and sometimes I have to push on the accelerator a little bit. Seems like it's my batteries that are draining. I charged up the one that was in my car, put it back in and it started great, but the next morning it was run down. Put the one from my celica in there...it worked fine. But now it's having problems starting again. It only has problems starting when the car has sat for awhile (engine and everything has cooled). I can turn it off after it's running, and turn it back on fine after 5 minutes. This should have been a new thread...my apologies, but any responses would be appreciated! Thanks!