# Audi TT OEM throttle pedal soliton1?



## Tesseract (Sep 27, 2008)

TTmartin said:


> ...
> 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)



TTmartin said:


> 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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## TTmartin (Feb 7, 2012)

Tesseract said:


> 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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## Tesseract (Sep 27, 2008)

TTmartin said:


> 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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## TTmartin (Feb 7, 2012)

Tesseract said:


> 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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## skooler (Mar 26, 2011)

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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## TTmartin (Feb 7, 2012)

skooler said:


> Just as an FYI,
> 
> I went down the route of spoofing the ECU.
> 
> ...


That's reassuring, I gave up early on trying to trick the ECU, convincing myself it's not necessary Without actully being 100% certain, expecting problems further down the line.

Was Your original throttle "fly by wire" if so did you use it?

I'm thinking about additional safety contactor control or maybe not necessary 
Do you rely on the soliton 1 via ignition / brake input for sole control or do you use any extra safety interlocks?


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## skooler (Mar 26, 2011)

Hi Martin.

Sorry, forgot to reply!

Yes I used the oem HEPA pedal. I disconnected 3 wires that went to the ecu and rerouted them to the soliton. If I ever find that the ecu needs the throttle signal for whatever reason an operational amplifier can be used to share it.

I currently rely on the soliton for safety. I'm running a clutched coupler so worse case is that I dip the clutch and let the motor be destroyed.

I did plan to use a second handbrake to operate an anderson connector. I decided against it as it mucked up the inside to much! Need to find a nice skinny handbrake and I may reconsider.

I'm now thinking of putting an EV200 in the boot between my 2 packs. This will be operated off the ignition. Helps with maintenance but also an added layer of safety.

I'd still prefer a mechanical disconnect such as an anderson connector.

Cheers,

Mike


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## Bowser330 (Jun 15, 2008)

Whats a clutched coupler?



skooler said:


> Hi Martin.
> 
> Sorry, forgot to reply!
> 
> ...


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## TTmartin (Feb 7, 2012)

Bowser330 said:


> Whats a clutched coupler?


Hi,
I think Skooler means he will put the clutch in to disengage the motor from the drive wheels so it would overspeed in a fault situation and disintegrate,
where as I would not have that choice due to not going with a clutch in my conversion


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## skooler (Mar 26, 2011)

TTmartin said:


> Hi,
> I think Skooler means he will put the clutch in to disengage the motor from the drive wheels so it would overspeed in a fault situation and disintegrate,
> where as I would not have that choice due to not going with a clutch in my conversion


Yep that's exactly what I meant! Not ideal but better than nothing!

I will still install an mechanical-electrical disconnect - an anderson connection attached to a handbrake lever looks the most likely option.

For the clutchless couplers could you not use neutral as an absolute last resort?

Cheers,

Mike


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## TTmartin (Feb 7, 2012)

skooler said:


> For the clutchless couplers could you not use neutral as an absolute last resort?
> Mike


For some reason I kind of thought without the clutch it might be hard to come out of gear under high load, never tried it?

By the way you mentioned an EV200 contactor, I looked on ebay and there appears to be a listing posted for this unit as second hand but 18 units available, from China maybe there old stock? only £32 +shipping sounds to good to be true, what do you think ?

Martin.


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## skooler (Mar 26, 2011)

I'll try pulling my vectra out of gear under load tomorrow. Don't think it's a problem. 

I purchased mine from the below link and they have been perfect. If you need more than one purchase them separately a week or so apart to dodge customs  (£60 is the low cutoff)

http://www.ebay.co.uk/itm/Kilovac-E...t=BI_Control_Systems_PLCs&hash=item43af8d50ee

To cover myself, I'm not recommending them, just posting my experience.

Cheers,

Mike


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## dtbaker (Jan 5, 2008)

skooler said:


> I will still install an mechanical-electrical disconnect - an anderson connection attached to a handbrake lever looks the most likely option.



mechanical pull of anderson connects while under load would not be *recommended*. without quick separation and magnetic blowout, chances are you'd have a hell of a arc and melt things.

take a look at your main circuit breaker(s), and see if you can add a cable pull, like an after market choke cable, to pull the breaker from the driver's seat.

...little off the original topic, but it caught my eye.

on the left of this image, note my main circuit breaker has a cable thru the toggle switch. I used a cheap choke cable run thru the firewall and mounted under dash next to window... visible to driver and emergency responders perhaps.


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## skooler (Mar 26, 2011)

dtbaker said:


> mechanical pull of anderson connects while under load would not be *recommended*. without quick separation and magnetic blowout, chances are you'd have a hell of a arc and melt things.
> 
> take a look at your main circuit breaker(s), and see if you can add a cable pull, like an after market choke cable, to pull the breaker from the driver's seat.
> 
> ...


Sorry to stray off topic...

I agree completeley.

But.....

In the (fairly unlikely) event of a runaway, risking the possibility of a (large) arc and possible melting is much preffered than certain motor destruction by dipping the clutch or using neutral.

Its normal use will be for maintenance. It wont be used if it is ever damaged by an arc - the chances are that the controller has some serious problems in this case and will likely need replacing before the car is usable again.

If circuit breakers were more widely available then that would be my preffered solution, although I'm not convinced that once welded shut, they would be as easy to open as an anderson with a lever?


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