RS4 Engine start button on S3

MarcQuinlivan said:
If I can't get it to work I can always try to bluff my passengers by turning the key at the same time as pressing the button!
Click to expand...

LOL Genius!

Anyway sorry MarcQ,

Do you know much about the immobiliser? As I was saying before it's only a case of touching 2 wires together to start the engine in basic terms. I've heard of immobilisers that work because the key sends a signal into the ignition when the key is in it. If that is the case then it will only be a case of stripping down the steering column and finding the right wires.
 
Yeah, there's a transponder in the key which communicates with something in the steering column to deactivate the immobiliser.

I'd be happy enough to just hook it into the starter cable rather than bypassing the immobiliser - at least that way i'll still need the key to start it. A car thief's job would be made so much easier if all he had to do was get in and press the button.

Anybody know which wire from the ignition feeds into the starter motor?
 
Well you wouldn't be bypassing the immobiliser, that signal will go via another route to the ECU. Once you have the steering coloumn off you can find whichever wire it is easily and then do the mod there and then.
 
There is one major problem with keyless go which to my complete and utter dismay I only realised a few weeks ago, 250 miles away from home and unable to leave my car !!! basically my brother had arrived home in his car and jumped out leaving the ignition running, I had been waiting for him so there was no need to stop the engine and lock it etc, problem arose when I arrived in london ( I live in manchester) only to find the idiot had started the car initially with keyless go and kept the key in his pocket............. so I couldnt switch the engine off, if i did i couldnt lock the car and it wouldnt start again.... Possible the most fun spent in an ncp ever !!!! still the new CL has a great dvd player in the dash..... thankgod for the dvds lying in the boot !
 
I know from experience that the Mercedes S600 and the various Bentley Continental variants display a warning in the dash if the transponder is not inside the car when you close the door.
 
I guarantee the novelty will wear off within 2 weeks

had one as standard fit on a previous car and using two hands, fumbling around in the dark to start the car was a pain in the ****
 
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I've already placed my order with my dealer. As luck would have it there's a dude on eBay selling bits from and accident damaged RS4 Avant.

He has this for sale.

c149_1.JPG
 
Ive got to say im pretty envious of all your mods Marc, lol. Everything you seem to be doing is something i would like to do with mine when i get it. Good job mine isnt red as well.

Rich
 
Hi Marc,

Will be eagerly waiting to see the results. Good luck!

klik
 
I'll be collecting the bits on Friday morning, so should hopefully get to the install at the weekend. Just need to get the button into my hands to see what connector is needed for it.

I assume it is going to be something like the ESP button with three wires - earth, lights and then the third wire is for the ignition.
 
MarcQuinlivan said:
I'll be collecting the bits on Friday morning, so should hopefully get to the install at the weekend. Just need to get the button into my hands to see what connector is needed for it.

I assume it is going to be something like the ESP button with three wires - earth, lights and then the third wire is for the ignition.
Click to expand...

Four wires I'd say + & - for the light and then input and output for the ignition.
 
My mistake - I was thinking about when I installed those illuminated buttons from Cargravo.

It is a 6-pin connector for the ESP button, but the Cargravo buttons have a connector which takes a tap off two wires for the lighting.

Obviously the button needs an input and output pin too. Sure, I'll soon find out!
 
Although it could work from 3 as it could use the ignition input to power the light. I'd recommend this anyway to save on wiring!
 
Think I'd prefer the light to be powered using the illumination circuit for the rest of the instrument panel\dash buttons. That way it'll be lit when the lights are on.

I've been reading where some people have hooked an earth from the ignition relay into the handbrake so that you can only start it when the handbrake is on.

I'd kinda like to stop some curious passengers from pressing the button while i'm driving, but don't want to have to apply the handbrake in order to restart the car if it happens to cut out while pulling out of a junction or on a level crossing. Might see if there's some way to hook it into the relay for the brake lights so that I have to have my foot on the brake to start it.
 
MarcQuinlivan said:
Think I'd prefer the light to be powered using the illumination circuit for the rest of the instrument panel\dash buttons. That way it'll be lit when the lights are on.

I've been reading where some people have hooked an earth from the ignition relay into the handbrake so that you can only start it when the handbrake is on.

I'd kinda like to stop some curious passengers from pressing the button while i'm driving, but don't want to have to apply the handbrake in order to restart the car if it happens to cut out while pulling out of a junction or on a level crossing. Might see if there's some way to hook it into the relay for the brake lights so that I have to have my foot on the brake to start it.
Click to expand...

But if you do that it'll be lit only when the lights are on, do you turn the lights on before you start the engine? The way I was suggesting means it is lit all the time when the ignition is on.

I don't know why anyone would want to only be able to start it with the handbrake on, for the reasons you have suggested. But the brake idea is a good one yes. It'd be worth finding out if the alternator has an auxillery output, you could then use that to inhibit the starter button when the engine is running. I guess you could use the alternator warning light output to inhibit the circuit though also.
 
Was stopped at a set of traffic lights on the way home and decided to see what would happen if I gave the key a quick turn. Nothing happenned. Seems to be some sort of wizardry at play to disable the ignition if the engine is already running. That should mean that the button also won't work if the engine is running.

The button only needs to be lit when the rest of the instruments are lit I think. The interior lights are on when before the key is turned to accessory so finding the button won't be a problem.
 
MarcQuinlivan said:
Was stopped at a set of traffic lights on the way home and decided to see what would happen if I gave the key a quick turn. Nothing happenned. Seems to be some sort of wizardry at play to disable the ignition if the engine is already running. That should mean that the button also won't work if the engine is running.

The button only needs to be lit when the rest of the instruments are lit I think. The interior lights are on when before the key is turned to accessory so finding the button won't be a problem.
Click to expand...

I did wonder myself whether the key was inhibited from turning to the start position phisically of if it is as you say. In which case yeah if you take the feed from the right place then you won't have problems if someone presses the button.

Aha you meant the interior lights feed! Not a bad idea but the lights go off when you turn the key to put the ignition on. I still think an ignition feed coupled with an alternator aux/warning light interlock would be perfect. i.e. you turn the key and the light comes on with the ignition you press the button and once the engine is running the light extinguishes.
 
You will probably find that there is a relay controlling the starter motor.
One side of the relay coil will be fed from the ignition switch when you turn it to the crank position (usually a positive feed), the other side of the relay coil will be fed by the engine ECU (usually an earth). This enables the ECU to stop the starter from engaging when the engine is running.

So as long as you fit the starter switch between the ignition switch and the relay you shouldnt have a problem.
 
As a safety feature, on the RS4 when you turn ignition key the DIS says to press the clutch pedal and press the start. hope this helps.
 
That actually makes more sense. It means that the car cannot be started if accidentally left in gear. I'll have a more detailed look at the weekend after I've picked up the stuff tomorrow.
 
It also does this on the S3 Marc and I was going to suggest this but I thought you knew. The problem is it most likely uses a switch on the clutch master cylinder to recognise whether the clutch is depressed or not. On a non S3 model this switch won't be there and I doubt there would be fittings for it either.
 
Yeah, I've just been looking at ETKA and the RS4 has a clutch switch and a brake switch in behind the pedals but the A3 does not.

I do remember seeing a photo of someone's S3 with the "press clutch" warning in the DIS now that you mention it.

I suppose if I can intercept the signal for the brake lights that will be enough.

The parts have just arrived with the dealer, so I've asked him to see if he can work out which connector I need for the bottom of the button.
 
I don't have an S3 but do have the Press "Clutch to Start" function. Thought all A3's had this tbh.
 
klik said:
As a safety feature, on the RS4 when you turn ignition key the DIS says to press the clutch pedal and press the start.
Click to expand...
That's there for a very good reason!

On the RS4 the start button connects to the ECU and all it does is "initiate" a start sequence. So all you have to do is tap the start button for a fraction of a second and the starter motor will run until the engine starts (or a timeout period) - so if you didn't have the clutch pressed your RS4 could be motoring across the car park if you had left it in gear!

So you can put on your seatbelt while the engine is starting because you have both hands free.
 
MarcQuinlivan said:
Is yours a manual? Perhaps it is only the manual ones that need you to press the clutch on!

Mine isn't as S3 and doesn't have this on the display.
Click to expand...

Yes mine is a manual. If it wasn't I wouldn't have a clutch pedal!
 
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boggysv said:
DSC03600.JPG


Threadjack: does anyone's knob glow like this? I like it, but mine doesnt seem to glow.

(please excuse the ****-esque question)
Click to expand...

Sorry to jump in... Is this possible to do on the S3? The glow around the gearshift looks great!
 
Not sure if i would risk destroying £90 worth of S3 gearknob for a few LED's.

But fair play to him it does look impressive
 
I like the look of it as well but im not sure it would be quite as straight forward as the guide would lead you to believe.

Rich
 
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