Hi,
i have brought up the old thread again, because the search revealed this relevant result.

 

It's about the problem of Throttle release during Left-Foot braking.
The Car is a Fabia RS (MK1) with manual Transmission and without Cruise Control.

Has anyone tried this, at the brake light switch disconnect the signal wire to
the ECU to enable Left-Foot Brake?

Or is there still a possibility via VCDS?

Maybe someone has dealt with this Problem in more Detail and can give me a hint?

 

Many thanks already

Richard

 

P.S.
If questions arise, I need the Left Foot Braking only for Trackdays...

I only found out this happens after fitting new brakes and giving the brake pedal a press with my left foot while still on the throttle with my right. The engine power was promptly cut out by the ECU resulting in a sudden unexpected lurch

Edited 7 September, 20223 yr by TMB

11 minutes ago, TMB said:

I only found out this happens after fitting new brakes and giving the brake pedal a press with my left foot while still on the throttle with my right. The engine power was promptly cut out by the ECU resulting in a sudden unexpected lurch

 

Yeah... new trousers were needed when mine did it.

7 minutes ago, AnnoyingPentium said:

 

Yeah... new trousers were needed when mine did it.

...and a new seat cover? 

3 minutes ago, e30_V8 said:

...and a new seat cover? 

 

... full fumigation more like...

I managed it in my mk1 by disabling (read pulling out) the brake light switch fuse.

Works but leaves the glow plug light flashing.

Iirc you can snip and join two wires on the connection to the brake light switch and that works without triggering the glow plug light.

Left foot braking is very useful, definately in that car.

Bit of a shame the mk2 won't let me do it the same way, would be handy with it being turbocharged.

Hi,

thank you for your answer.
In the 4-pin brake light switch there are actually 2 switches in one housing, the switch between terminals 1 and 4 is a make contact for the brake light and the switch between terminals 2 and 3 is a break contact for the signal to the ecu.

I'll short-circuit connection 2 and 3 with a switch, like you said, and then I'll see if it works for me too...

 

I have seen that there is also a 2-pin switch on the clutch pedal, do you know what function it has?

Does it also have a safety function and send a signal to the engine control unit like the brake pedal switch if the accelerator pedal sensor gets stuck at "full throttle"?

 

Have a good start to the new week

Richard

One function of the clutch switch is to disengage cruise control if that is fitted and active.

Not sure if there are other functions, but there probably are because it is still fitted on cars that left the factory without CC.

The clutch pedal switch is there to make it easier to change gear. If you rev the car in netrual, clutch up, the revs fall slowly. If you put the clutch down, you'll notice they drop really quickly. Easier to tell if you keep blipping the throttle and moving the clutch up and down. I summise that with the clutch up, if you let off the throttle, the ECU keeps injecting some fuel so you don't get hit with a huge amount of engine braking. But obviously, when you want to change gear, you need to revs to fall quickly, so when the clutch goes down the ECU cuts more fuel.

 

See SSP 209 for details on the above

 

To disable this "nicely" you need to flash the ECU and change one byte. Need to use Galleto/MPPS or similar.

 

 

Also the cutting of power in the first place is a safety feature, because its assumed the accelerator may be stuck, so you're trying to brake. The SSP also makes reference to the fact that, if one of the pair of brake light switches fail, then the ECU will reduce power.

If anyone has a file they want this doing to, let me know and I'll do a guide. Takes 30 seconds with a hex editor

Can you not just switch traction control off? We used to switch off traction control to left foot brake for bedding in new brake pads.

@grumpy1Do you have a Mk2 or a Mk1 Fabia?

 

Traction Control / ASR  does not stop you using the brake pedal to bed in brake pads, why would you need to switch it Off if you have it. 

1 hour ago, grumpy1 said:

Can you not just switch traction control off? We used to switch off traction control to left foot brake for bedding in new brake pads.

You shouldn't be able to on a stock Fabia. The ECU has a check where if the thorttle isn't in the idle position (less than 1%) and the brake is pressed, the fuel ramps down to idle. There is a software switch to disable this check. It is also disabled if you have a faulty brake switch.

TKW describes how to have both brake and accelerator active quite early on page 1.

The check happens when the brake pedal is pressed, which explains why TKW method works. When you release the accelerator the throttle position falls to 0 and let’s the ECU pass the check, when you accelerate again the check isn’t ran as long as the brake pedal is still down.

I disabled the power cut in the ecu mapping.  Just never got round to learning left foot braking properly.

29 minutes ago, faboka vrs said:

Just never got round to learning left foot braking properly.

 

Likewise, became well acquainted with my windscreen though!

The other benefit is it lets you transition between brake and accelerator faster, which is why circuit racers use a left foot brake. As said though, a standard vrs doesn't have great throttle response. 

 

I use it a bit on twisties if I'm in a car with the throttle response to do it (MK2 caddy SDI is the only vehicle I have on the road that benefits from it, it doesn't seem to cut the throttle, despite having fly by wire and a multipin brake switch). Growing up driving tractors makes braking with either foot easier.

14 minutes ago, StevesTruck said:

The other benefit is it lets you transition between brake and accelerator faster, which is why circuit racers use a left foot brake.

Yup and helps smooth out weight transfer which was the reason I wanted to disable it. I’m just not good at it haha