Heel and Toe problem

B

bjorno

Member
 Barrow in Furness
I had the crank case vent valve changed by an indy last week to cure a missfire at tickover and oil consumption and since picking the car up had noticed on the couple of times that I tried that it wasn't responding when i tried to rev match when changing down. I discovered last night at traffic lights that the accelerator has no effect at all if you press the brake at the same time. So if in Neutral with the handbrake on i put my left foot on the brake I can floor the gas and it stays on tickover, if i release the brake the revs rise. I rang the indy this morning to ask if something had been disabled when they ran diagnostics to find the CCV fault and they were having none of it, the guy said maybe it has always been like that..............no it bloody wasn't!!

This is obviously an electrical problem and therefore completely outwith my understanding, does anyone know enough about the hardware/software that controls the throttle to throw some light onto what may be causing this and how it might have been caused

as ever, thanks in anticipation

Bjorno
 
Very interesting! VW's have this 'feature' which i totally hate, but i've never heard of a Bimmer doing it...

I'd definitely get on to them harder about it, mentioning you are unable to heel/toe anymore etc. Sorry i cant be of any help yet, ill have a little research! ;)

Edit: just out of curiosity id probably try taking the battery off for 15mins to remove the cars short term memory. When re-attaching perform a throttlebody reset (detailed on here if you search: ign on 10 sec, off 10 sec, on again 10 sec, start car).
 
EdButler said:
Very interesting! VW's have this 'feature' which i totally hate, but i've never heard of a Bimmer doing it...
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Got to be honest I've never tried heel-and-toeing on my Z4, but I had previously tried it on my VAG group car (a Seat, so VW in drag) and found the same. I thought it was a characteristic of electronic throttles / drive-by-wire, and wasn't restricted to VAG cars, but that's not the case?
 
I tried the throttle reset last night and it hasn't made a difference, do you get any confirmation of a reset like a beep or light etc, wondering if my 10 seconds were long enough? I'll try disconecting the battery tomorrow, before i do though does that adversly effect anything else, ie will i need a code to get the radio working again.

A11y, it's definately not the case on z4's, heel toeing worked fine before.

The indy seemed adement that they didn't turn anything on or off with the throttle, I'm reluctant to start kicking up a fuss unless someone can add some weight to my theory that a diagnostic could somehow have messed it up
 
I dont know if Z4 radios need a code, probably yes...

It sounds like some parameter has been enabled which stops double pedal input, probably for an Auto as thered be no reason to do this.

Can anyone with an auto confirm this is not possible? Unfortunately they may not look in a "Heel and Toe" thread! :poke:

Wheres CJ10Jeeper!?
 
Cheers, I'll have to try heel-and-toe in my Z4 then...

Radio code - NOT required when I changed the headunit in my 54-plate Z4. I replaced the basic headunit with a newer business headunit from a facelift car and neither unit required a security code. Quite surprised at that, most nowadays always have some sort of code.
 
never needed to heel and toe to be honest... not needed when you hardly ever brake and clutch at the same time :D
 
gannet said:
never needed to heel and toe to be honest... not needed when you hardly ever brake and clutch at the same time :D
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I know, I know, I really shouldn't be doing both ever according to the IAM but I've slipped back to overlapping mine a bit now :oops:
 
a11y said:
gannet said:
never needed to heel and toe to be honest... not needed when you hardly ever brake and clutch at the same time :D
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I know, I know, I really shouldn't be doing both ever according to the IAM but I've slipped back to overlapping mine a bit now :oops:
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:rofl:

overlapping brake and clutch is inevitable even when driving to IAM standards in certain circumstances (approaching a left turn while going downhill for example)... Ive been IAM since I was 19 so it is fairly ingrained to my driving :D. Key aim is to minimise it.
 
I've checked this on my car and there's no problem in using the throttle whilst applying the brake so something is not right with your car.
 
Interesting. Reading about the new Mazda2, seems that for automatics, they're building this in due to Toyota's acceleration problems. If your foot is on the brake, you can't get the accelerator to respond. Wonder if they've allowed for all us manual drivers or if they're using the same code?
 
Certainly not a problem with mine.

I may or may not have ended the life of my last tyres by doing silly manoeuvres that require both the accelerator and brake to be used at the same time.......
 
sk93 said:
Certainly not a problem with mine.

I may or may not have ended the life of my last tyres by doing silly manoeuvres that require both the accelerator and brake to be used at the same time.......
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:D :rofl:

Yeah definitely shouldn't be the case on a Manual (proper ;)) transmission... Would like to know about our fellow Auto owners though!

bjorno: It may be better posting on other BMW forums like BimmerForums.co.uk or E46Fanatics.com. Theres a fair few techno gurus on them :)
 
gannet said:
I will try in our mazda2 and let you know :)
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Let me rephrase, it's for the NEW Mazda2 that is just now hitting the States. :P

Heck the Fiesta is just now being sold. Hope SVT gets hold of it-it would be a little rocket.
 
Smokin said:
gannet said:
I will try in our mazda2 and let you know :)
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Let me rephrase, it's for the NEW Mazda2 that is just now hitting the States. :P

Heck the Fiesta is just now being sold. Hope SVT gets hold of it-it would be a little rocket.
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does it look like this: Mazda2

if so, then unless they make changes then heel and toe is possible :D
 
Yep, that's what it looks like. 2011s are the first ones here.

I can't find the darned article I read this morning that mentioned the brake override of the accelerator in the auto tranny model. If I run across it, I'll link it.
 
Ah, found it:


http://www.latimes.com/business/la-fi-car-review-20100812,0,5276084.story

"The last thing drivers of small cars want is to lose an unintended battle with a large object. Traction control, stability control, anti-lock brakes and tire pressure monitoring are standard. So is brake override, a new system that gives priority to the brakes should the accelerator and brake pedals be pressed simultaneously.

Inspired by Toyota's sudden-acceleration fiasco, Mazda's brake override is debuting on the Mazda2 and will roll out to all other Mazda models by the end of the 2011 model year."
 
You don't rev the engine often in a car with an automatic transmission, but how about when you're working on it or listening for something-foot on brake, tranny in N or P and giving a bit of gas? Will this override prevent this? Interesting questions. Of course, as I understand it, our Z4s (and the rest of the BMWs with drive by wire) allow the ABS to override the throttle. Saw it in a Roundel article a few months back.
 
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