tps voltage

subarufamily · #1 02-18-2008, 01:41 PM

I bought the subaru rx from rebecca and was curious as to the tps voltage was the same as the svx .5 volts ? the rx was sick and needed the coolant temp sensor replaced and was informed that the tps was out of range so was wondering if the voltage was the same so i can reset it.

Hocrest · #2 02-18-2008, 05:08 PM

I don't know but if you go over to USMB I'm sure they can help you out in no time...

Go to the "Older Generation" forums.

gsodonis · #3 02-18-2008, 05:22 PM

Did you mean TPS reports?

Suby Fan · #4 02-19-2008, 09:26 AM

yes it is its universal with all most every car... should be between .45-.55 .5 optimum

svx_commuter · #5 02-19-2008, 11:06 AM

I have recently set the TPS all the way one way in the slots. The ECU compensates for it, no problem. The learning circuit in the ECU does the compensation.

The TPS is prone to wear if you drive a lot with your gas foot in the same place each time. This wears a spot in the TPS resistor contacts. Not good for the TCU since it depends on the TPS reading.

I say about 130K miles of highway driven wear them out. Moving it all the way in the slots has it work on a spot that is not worn at all. In normal driving the TPS hardly moves at all so it is pretty easy to put a wear spot in it.

There is other setting information on this site that says to use 2.0 volts for setting and that depends on what two pins out of the three you connect to.

If it's bad I will move the position and try that first as that little TPS is costly.

I have also had some strange problems on a 1.8 Impreza where the TPS was bad. No CEL or other indicators. The TPS on the 1.8 impreza and SVX look the same.

Take care of that SVX

John

Suby Fan · #6 02-19-2008, 01:16 PM

Quote:

Originally Posted by svx_commuter

I have recently set the TPS all the way one way in the slots. The ECU compensates for it, no problem. The learning circuit in the ECU does the compensation.

The TPS is prone to wear if you drive a lot with your gas foot in the same place each time. This wears a spot in the TPS resistor contacts. Not good for the TCU since it depends on the TPS reading.

I say about 130K miles of highway driven wear them out. Moving it all the way in the slots has it work on a spot that is not worn at all. In normal driving the TPS hardly moves at all so it is pretty easy to put a wear spot in it.

There is other setting information on this site that says to use 2.0 volts for setting and that depends on what two pins out of the three you connect to.

If it's bad I will move the position and try that first as that little TPS is costly.

I have also had some strange problems on a 1.8 Impreza where the TPS was bad. No CEL or other indicators. The TPS on the 1.8 impreza and SVX look the same.

Take care of that SVX

John

Just about all of what you just said is wrong

Trevor · #7 02-19-2008, 04:09 PM

If the TPS is worn to the point whereby contact, or the conductive plastic resistance element is faulty, there will be any error in the signal regardless of how you set it the adjustment. This "learning stuff" is confusing and can not be applied in this instance. In point of fact by setting the unit incorrectly, you will have compounded two errors.

Please quote the reference you have found published referring to 2.0 volts.

subarufamily · #8 02-19-2008, 10:02 PM

thank you for all the info. YES the little square tps is $322

so if it can be reset and/ or cleaned this was my hope. I was unaware that it could be moved and the computer would learn it.

Trevor · #9 02-20-2008, 01:14 AM

Quote:

Originally Posted by subarufamily

thank you for all the info. YES the little square tps is $322

so if it can be reset and/ or cleaned this was my hope. I was unaware that it could be moved and the computer would learn it.

It can NOT be moved from what is the correct position in the hope that ECU will adjust for the wrong position., i.e. "learn it".

Before you do anything, go here and read all about it.

http://www.subaru-svx.net/photos/files/How-To/14293.pdf

svx_commuter · #10 02-20-2008, 11:02 AM

Quote:

Originally Posted by Suby Fan

Just about all of what you just said is wrong

Oh yes I agree this is not what is considered correct and took a long time for me to try this and guess what? Well all I can tell you is that it is working just fine!! No effect on the MPG either.

svx_commuter · #11 02-20-2008, 11:04 AM

Quote:

Originally Posted by Trevor

If the TPS is worn to the point whereby contact, or the conductive plastic resistance element is faulty, there will be any error in the signal regardless of how you set it the adjustment. This "learning stuff" is confusing and can not be applied in this instance. In point of fact by setting the unit incorrectly, you will have compounded two errors.

Please quote the reference you have found published referring to 2.0 volts.

Think about wear the wear point is. This is well within the range voltage setting.

I may have that 2.0 volts wrong but I will look around. Don't forget there are three wires and they do not read the same.

svx_commuter · #12 02-20-2008, 11:07 AM

Quote:

Originally Posted by Trevor

It can NOT be moved from what is the correct position in the hope that ECU will adjust for the wrong position., i.e. "learn it".

Before you do anything, go here and read all about it.

http://www.subaru-svx.net/photos/files/How-To/14293.pdf

I have moved the TPS this was few years ago with the engine running. I was looking for a higher idle speed. After a few starts and stops the idle came back down. That is learning by the ECU in my book.

This last time I turned it all the way with the engine off. So gues what? No change in idle speed, no CEL, no change in MPG and the tranmission is shifting better since it's off the wear spot.

svx_commuter · #13 02-20-2008, 11:13 AM

Quote:

Originally Posted by subarufamily

thank you for all the info. YES the little square tps is $322

so if it can be reset and/ or cleaned this was my hope. I was unaware that it could be moved and the computer would learn it.

I have not been successful in cleaning this thing. If it worn that is a problem. Clean does not put worn material back. I have also tested one out of the SVX. Check out my old locker and see what happens when it wears. I took a chance when I moved it this time and so far so good. I was trying to get the transmission to shift better.

The TPS is prone to wearing out. Periodic cleaning BEFORE it wears is a better way to keep it lubricated and not wear. Just like that speed sensor in the tranny.

Take care of that SVX,

John

Trevor · #14 02-20-2008, 03:01 PM

Quote:

Originally Posted by svx_commuter

I have moved the TPS this was few years ago with the engine running. I was looking for a higher idle speed. After a few starts and stops the idle came back down. That is learning by the ECU in my book.

This last time I turned it all the way with the engine off. So gues what? No change in idle speed, no CEL, no change in MPG and the tranmission is shifting better since it's off the wear spot.

The learning aspect so often referred to, tends to be a play on words initiated by the sales department, as a means of glorifying a what is a standard practice used within control systems. The use of a feedback loop is an essential component in most systems involving electricity, hydraulics air, temperature, etc.

A change in the controlled medium is sensed, the result measured to be fed back to the adjusting mechanism. A change is signalled and the result again measured and fed back. The process continues until equilibrium is reached and medium stabilised at the desired parameter.

I guess this system of feed back and response, can be likened to learning, in a vague sort of manner.

The idle speed is determined by the ECU on the basis of sensing engine RPM and correcting other parameters in order to adjust same. The ECU has learned nothing, it is simply operating normally and made an adjustment to counter a changed input. It has reacted in the same way as it does in countering a change in other factors.

After the alteration suggested, the overall signal voltage from the ECU has been altered from optimum and regardless of placebo, and functions relating to the TPS will have been altered.

Trevor · #15 02-20-2008, 03:20 PM

Quote:

Originally Posted by svx_commuter

I have not been successful in cleaning this thing. If it worn that is a problem. Clean does not put worn material back. I have also tested one out of the SVX. Check out my old locker and see what happens when it wears. I took a chance when I moved it this time and so far so good. I was trying to get the transmission to shift better.

The TPS is prone to wearing out. Periodic cleaning BEFORE it wears is a better way to keep it lubricated and not wear. Just like that speed sensor in the tranny.

Take care of that SVX,

John

The TPS resistance comprises conductive plastic, for the very reason that this does not wear, being of constant density throughout. An old fashioned carbon surfaced or wire wound component is not involved. The movement of the contact point is also much more sophisticated than of old.

Lubrication as such should not be attempted. The electrical surfaces should not be contaminated with oil, as this comprises an insulation against electricity. An electrical cleaning agent must be used. Once clean, the surface of conductive plastic is inherently friction free.

Any debris will prevent proper contact with the conductive plastic surfaces, thus upsetting the resistance at specific points during rotation. Whatever, there can be general wear and tear effecting optimum performance, which will require replacement at some point.