awesome times setting TPS (not really)

[jetjock]

Had you done it using the diag system like Nick is suggesting all you would have needed to do is loosen the TPS. No moving of hoses or disconnecting of anything. Even more important is you wouldn't have made the pin mistake because no measuring would have been involved. Nor would the TSRM have been needed. The hassle is having to look at the MIL although two people solves that problem. My own method is to measure voltage on IDL because voltage is what the ECU deals with.

 

[DeMoN2318]

Here is 105/hr worth of free advice. You can watch for 51 then adjust to when it shuts off. That did in fact happen on the line at Toyota.

Code 41 not 51

 

[jetjock]

No, 51. 41 is related to the VTA signal

 

[DeMoN2318]

My bad. I didn't see 51 below 71 in the TSRM

 

[jetjock]

It's ok. Probably a touch of hypoxia. Check the O2 flow to that mask :icon_razz

If you're not using it this is a good page for codes:

http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

 

[IndigoMKII]

Had you done it using the diag system like Nick is suggesting all you would have needed to do is loosen the TPS. No moving of hoses or disconnecting of anything. Even more important is you wouldn't have made the pin mistake because no measuring would have been involved. Nor would the TSRM have been needed. The hassle is having to look at the MIL although two people solves that problem. My own method is to measure voltage on IDL because voltage is what the ECU deals with.

What is the voltage on the IDL that the ecu is looking for? I know most people with SAFC's will go by the IDL voltage on screen when setting the tps too.

 

[jetjock]

It's my understanding the SAFC only displays VTA but having never messed with one I could be wrong.

Since IDL is pulled up internal to the ECU it will be high when the TPS switch is open (throttle off idle, input floating) and low when the switch is closed (throttle on idle, input grounded). The TSRM, at least some I've seen, say IDL will be battery voltage when high while others say it'll be 5 volts. I have never seen one be battery voltage nor, since it's part of the EFI sensor system, does it makes sense it would be.

Put simply it'll be close to 0 volts at idle and 5 volts at all other times. Having never played with it I don't know exactly what level the ECU judges the throttle to be off idle. I'm assuming it's near whatever the 2K ohm max spec on the TPS figures out to be or whatever the "legal" high is for the type of logic involved. Probably around 1.8 volts but it doesn't really matter because of the pull up.

When the TPS is set properly VTA will vary from around 200 mv at idle to appx 3.6 volts at WOT. This is in contrast to the nearly 5 volts the book states.

 

[IndigoMKII]

It could be VTA on the SAFC, I was merely going by an assumption.

That's nice to know though about the voltage though.

 

[DeMoN2318]

It's ok. Probably a touch of hypoxia. Check the O2 flow to that mask :icon_razz

If you're not using it this is a good page for codes:

http://www.cygnusx1.net/Supra/TechTips/engine_error_codes.aspx

Bookmarked!! Thanks!

oopps...O2 valve was closed...I thought I felt a little too smiley! good watchin out

 

[Insidious Surmiser]

Had you done it using the diag system like Nick is suggesting all you would have needed to do is loosen the TPS. No moving of hoses or disconnecting of anything. Even more important is you wouldn't have made the pin mistake because no measuring would have been involved. Nor would the TSRM have been needed. The hassle is having to look at the MIL although two people solves that problem. My own method is to measure voltage on IDL because voltage is what the ECU deals with.

that sounds pretty simple either way... it was just me working on it... the way I did it was REALLY simple too. like I said, all I had to move was 2 vacuum lines, and unplug the TPS (still don't think you even need to do that to see if there's a break in continuity, if there wasn't it'd mean your harness was shorting) the key to getting the TPS loose w/ out moving everything was a phillips tool shaped like an allan key

but yes, the safc displays VTA for sure... I used to use that all the time on the highway (in conjunction w/ vacuum/boost gauge) to hit 30mpg...

 

[jetjock]

If it was simple you wouldn't have spent so much time trying to figure it out and this thread wouldn't exist. And I said you *risk* measuring circuit resistance by not disconnecting. Point is it's very bad technique yet you keep telling us what a sierra hotel mechanic you are. I r corn-fuzed...

 

[Nick M]

What is the voltage on the IDL that the ecu is looking for? I know most people with SAFC's will go by the IDL voltage on screen when setting the tps too.

http://www.autoshop101.com/forms/h24.pdf

Page 23 and 24. And it wouldn't hurt to read all of it to be more familiar.

 

[Nick M]

Having never played with it I don't know exactly what level the ECU judges the throttle to be off idle. I'm assuming it's near whatever the 2K ohm max spec on the TPS figures out to be or whatever the "legal" high is for the type of logic involved. Probably around 1.8 volts but it doesn't really matter because of the pull up.

I read it in one of the older books, like 850 or something. But I am not going downstairs to read it.

 

[jetjock]

See, there again is more documentation that shows IDL may be connected to +B and that it may be anywhere from 5 to 12 vdc when pulled up. I've never seen anything except 5. Go figure. Maybe we can convince 3p to poke around an ECU and see whether that input is pulled up by +B or Vc

 

[IndigoMKII]

http://www.autoshop101.com/forms/h24.pdf

Page 23 and 24. And it wouldn't hurt to read all of it to be more familiar.

Thanks, I actually have that printed out as I found it the other day and said "DOH" lol

That was one of my lesser moments if you will.

 

[Nick M]

See, there again is more documentation that shows IDL may be connected to +B and that it may be anywhere from 5 to 12 vdc when pulled up. I've never seen anything except 5. Go figure. Maybe we can convince 3p to poke around an ECU and see whether that input is pulled up by +B or Vc

I am going after the book. I don't have anything to do right now. Babysitting....

In 852, which is is later and has the 1MZFE and other OBD2 in it has a spec. They say 0V at idle, and B+ when open. And that might not apply to the older TCCS.

http://www.autoshop101.com/forms/h33.pdf

Page 3 of 8. Or page 2-15 in the hard copy.

 

[Nick M]

Thanks, I actually have that printed out as I found it the other day and said "DOH" lol

That was one of my lesser moments if you will.

He has everything that I have, and then some. I have nothing on hybrids, other than what I cribbed from him.

 

[Insidious Surmiser]

If it was simple you wouldn't have spent so much time trying to figure it out and this thread wouldn't exist. And I said you *risk* measuring circuit resistance by not disconnecting. Point is it's very bad technique yet you keep telling us what a sierra hotel mechanic you are. I r corn-fuzed...

lol, hotel mechanic sounds about right (I've done that before)... I've got the certifications, but an extreme lack of experience, and pretty much no tools. it was simple as hell, you of all people ought to know. the extent of complexity is that I had the diagram upside down. flip it the other way and it's no issue at all... I didn't need to measure resistance anyhow. all I needed to know was if the circuit was closed or open.