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Old 07-14-2012, 05:19 PM
TTmartin TTmartin is offline
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Default Audi TT OEM throttle pedal soliton1?

Looking for guidance,
After much cursing/swearing, stiff neck, (god I'm getting old)
I managed to remove the drive by wire throttle pedal from my Audi TT to enable testing of wires as unable to test in position.
There are 2 separate outputs from the pedal, signal one is .7 volts at no throttle to 4.7 volts at maximum throttle. Signal two is half of signal 1.
As per soliton 1 hand book quote, 0 to 5 volt signal is required so if I use signal 1 to controller and calibrate as per soliton 1 instructions, will this work ok?
The hand book states that OEM throttle can be used if guide lines are followed but calibration may be difficult. Has anyone experienced what the difficult bit is?
Is there any advantage in removing the OEM throttle and using soliton throttle pot,
I don't want to go to the trouble of refitting OEM throttle if it is likely to give problems.
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Old 07-15-2012, 05:48 AM
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Tesseract Tesseract is offline
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Default Re: Audi TT OEM throttle pedal soliton1?

Quote:
Originally Posted by TTmartin View Post
...
There are 2 separate outputs from the pedal, signal one is .7 volts at no throttle to 4.7 volts at maximum throttle. Signal two is half of signal 1.
As per soliton 1 hand book quote, 0 to 5 volt signal is required so if I use signal 1 to controller and calibrate as per soliton 1 instructions, will this work ok?
You could use either signal, actually, but the wider span of the first signal will give you better throttle resolution (ie - amps of motor current per throttle volt)

Quote:
Originally Posted by TTmartin View Post
The hand book states that OEM throttle can be used if guide lines are followed but calibration may be difficult. Has anyone experienced what the difficult bit is?
I was intentionally vague when I wrote that because each car with drive-by-wire throttle does it a little differently, but the difficulty is not so much with obtaining the signal, it's more from the consequences of cutting the engine computer (ECU) out of the throttle loop entirely.

To use one of the above identified signals just tap the corresponding signal wire and connect it to the THROT input on the Soliton controller. This bypasses the ECU so you won't be able to use cruise control, which is a minor inconvenience, but if the car has an automatic transmission then it will almost certainly shift roughly if it even shifts at all.

If you pull the signal from the position feedback pot on the throttle butterfly valve (aka, the TPS) then you have to fool the ECU into thinking there is still an engine present and that it is working at least somewhat as expected. This may entail "spoofing" (i.e., recreating) some or all of the signals from the engine sensors such as coolant temp, crankshaft position, camshaft position, manifold air pressure (MAP), mass air flow (MAF), etc... Needless to say, *this* is what is often very difficult.

The programmable outputs on the Soliton controllers can help here, though; particularly the "gauge driver" functions. These functions represent an operating parameter (e.g. - battery voltage and current, motor voltage, current and power, etc.) with a 0-100% duty cycle square wave. For example, "motor kW" is a close analogue to mass air flow, so with the proper scaling of this gauge driver output you can do a pretty good job of spoofing the MAF signal.

Obviously, this is just a cursory overview of the situation but it gives you an idea of what to consider.
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Old 07-15-2012, 07:12 AM
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Default Re: Audi TT OEM throttle pedal soliton1?

Quote:
Originally Posted by Tesseract View Post
You could use either signal, actually, but the wider span of the first signal will give you better throttle resolution (ie - amps of motor current per throttle volt)
I was intentionally vague when I wrote that because each car with drive-by-wire throttle does it a little differently, but the difficulty is not so much with obtaining the signal, it's more from the consequences of cutting the engine computer (ECU) out of the throttle loop entirely.

If you pull the signal from the position feedback pot on the throttle butterfly valve (aka, the TPS) then you have to fool the ECU into thinking there is still an engine present and that it is working at least somewhat as expected. This may entail "spoofing" (i.e., recreating) some or all of the signals from the engine sensors such as coolant temp, crankshaft position, camshaft position, manifold air pressure (MAP), mass air flow (MAF), etc... Needless to say, *this* is what is often very difficult.
Thank you for response,

I started to go the route of "spoofing" the ECU, but realized that although possible it would be difficult and time consuming for (Me) to do
So I then removed Throttle pedal to find there is a 5 volt supply there without having to spoof the ECU.
It's a manual transmission, cruise control not required.
But am I wrong in thinking I don't need to "spoof" the ECU.
All functions required on the car seem to work ok with IGN on, the soliton1 will be my ECU so why "spoof"
Am I missing something?
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Old 07-15-2012, 11:25 AM
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Default Re: Audi TT OEM throttle pedal soliton1?

Quote:
Originally Posted by TTmartin View Post
All functions required on the car seem to work ok with IGN on, the soliton1 will be my ECU so why "spoof"
Am I missing something?
You might want to check the air-conditioning, specifically, as it often is disabled when the ECU is in "limp home" mode.

Otherwise, yeah, you are off to a good start converting a manual and not having (or wanting, anyway) cruise control.
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Old 07-15-2012, 12:19 PM
TTmartin TTmartin is offline
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Default Re: Audi TT OEM throttle pedal soliton1?

Quote:
Originally Posted by Tesseract View Post
You might want to check the air-conditioning, specifically, as it often is disabled when the ECU is in "limp home" mode.

Otherwise, yeah, you are off to a good start converting a manual and not having (or wanting, anyway) cruise control.
Great, air-con already removed, decided I would do without as we don't get much of a summer here in the UK anymore, also its one less thing to drive.
I have installed an electric power steering pump and vacuum pump for brakes, both controlled separately from any ECU involvement, so hopefully I won't hit any major problems.

Thank you for your help and advice.
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Old 07-17-2012, 01:29 AM
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Default Re: Audi TT OEM throttle pedal soliton1?

Just as an FYI,

I went down the route of spoofing the ECU.

Complete PITA!

Then I took a step back to see what it actually does and what I need it to do... all mine does is the power steering. Not really worth the effort of spoofing every signal!
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