So I deduce from the above that BOTH switches must have failed, since I can’t replicate the function of the fuel cut out switch. Perhaps it is making intermittent contact . Can’t think why it would be corrected by blipping the throttle though. Does anyone know if the switch is “open circuit” normally, and “closed circuit” when braking, or the other way round? If the former, maybe I should just disconnect it? ( after footling about with the new brake light switch terminals, they are too well protected to get a tester on them, without getting the guard plate off and exposing the neoprene nightmare again.)
P.s where can I get one of those gadgets that makes a V8 noise, please?
Normally open as you guessed.
Here goes --
Now that is clever.
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
Could anyone confirm how the pedal cut off switch should work. Does shut the engine off if you press the brake? Mine doesn’t. Does the car have to be moving, in gear, or otherwise?
Hi SFG, I can't help, I only know the brake cut off the fuel because I dry the brakes off after washing the car, I drive gently with the brake lightly on while on a light throttle just to warm the discs and pads so the water evaporates and doesn't mark the discs or pads whilst in the garage, Hope you sort it soon
2017 Mercedes Benz SLC 200 AMG. 2019 Mercedes Benz GLA 200 AMG Now Ex-Mogger!
Could anyone confirm how the pedal cut off switch should work. Does shut the engine off if you press the brake? Mine doesn’t. Does the car have to be moving, in gear, or otherwise?
Stuart I wish I could as I sense your frustration at this fault, it does seem likely that both switches were suspect to me and intermittent with first the brake light problem and later the hesitation issue. I also wish I still had my 4/4 Sport so I could carry out some back to back checks for you but I don't however logic tells me that the ECU would have to have enough information to know that it was travelling i.e. engine under load before it attempted to cut the fuel to a tick over speed. Now I haven't read that anywhere but to me it's logical.
There are others with far more knowledge of these models that have written books on them that will hopefully summon the courage to step forward and help you as well.
If you were closer I'd love to help you with this one.
Good luck with it.
2009 4/4 Henrietta 1999 Indigo Blue +8 2009 4/4 Sport Green prev 1993 Connaught Green +8 prev
Could anyone confirm how the pedal cut off switch should work. Does shut the engine off if you press the brake? Mine doesn’t. Does the car have to be moving, in gear, or otherwise?
I might have this wrong but in normal use you'd be on the gas then off the gas an onto the brake with right foot and this would cut the gas off.
If you revved the car with your right foot and braked with the left foot this isnt what you'd normally be doing in practice as you're still on the gas and using both feet.
Good points above. I was going to rush out and check , revving up and the moving my foot on to the brake. But that would be the same as just taking my foot off the accelerator , the engine would slow down to tick over 🤔
If the system is working properly on my car, and if the fuel cut off is there as a last resort for when the accelerator is stuck open, I can tell you that it doesn’t do this!
Still mystified
Originally Posted by exbiker
Hi SFG, I can't help, I only know the brake cut off the fuel because I dry the brakes off after washing the car, I drive gently with the brake lightly on while on a light throttle just to warm the discs and pads so the water evaporates and doesn't mark the discs or pads whilst in the garage, Hope you sort it soon
Hi exbiker - do you mean the engine cuts to tickover When you are applying light throttle and braking at the same time ? So the brake over-rides the throttle?
This is from the 350z forum. Its possible the switch may reduce the revs rather be an on/off switch which could tie in with your hesitancy problem
Quote
I seem to recall Raceboy saying that he still had throttle while doing heavy braking heel-toes, but only like 1/3 as much as he should. So he could still blip on a heel-toe, but it was like being in slow motion. I've noticed this too. My blips rise faster if I'm not braking heavily (or not braking at all).
My 2011 4/4 has two switches. But I had the accelerator pedal modified so I can heel & toe. The engine blips fine so I guess the 2nd switch is just a back up brake switch.
Ice pack: i hoped that, but then my brake lights failed. Also a second switch is not shown on the wiring diagram. ( but then neither is a fuel cutout switch!)
