Engine cuts out when braking hard, or just cuts out

[melb100]

Hi

while the car is in the garage awaiting diagnosis on a front end noise, I thought I would ask for opinions on why the engine cut out today while taking it to the garage, as i had to brake very hard because someone decided to reverse onto the main road not far in front of me🤬. this happened the other day as well but I wasn't braking at all it just cut out, but both times I did notice no dash lights came on. The engine stared up again and drove no problem on both occasions. 

I have said to the mechanic to investigate this a as well, but just wondered if any body has had the same issues.

thank you

[nitten_traveller]

Does it usually happen when you push the clutch down?  Clutch down, revs drop to zero, engine cuts out, but when you lift the clutch to engage a gear (when still moving) the car restarts?  If so it could be the throttle controller.  This was the cause of a similar problem with an older car of mine.  Cost about £80 to have it removed, cleaned and reassembled, problem solved.

[pistolpete1]

Occasionally my Focus (mk 2.5) cuts out. It's normally when coasting on the clutch whilst slowing down. Don't notice it till the steering feels heavy when power assist stops, then I notice all the lights on the dash.

Seems the revs go below 800 when the clutch is pressed, and sometimes it goes too low and stalls.

It has only happened a dozen times or so in 3 years, so I haven't bothered looking into it, and getting it fixed.

 

[melb100]

On 7/25/2018 at 9:28 AM, nitten_traveller said:

Does it usually happen when you push the clutch down?  Clutch down, revs drop to zero, engine cuts out, but when you lift the clutch to engage a gear (when still moving) the car restarts?  If so it could be the throttle controller.  This was the cause of a similar problem with an older car of mine.  Cost about £80 to have it removed, cleaned and reassembled, problem solved.

@Nitten_traveller, Yes when I had to do the emergency stop, the clutch was pushed down and braked hard, when it just cut out I was just going through the gears picking up speed and it cut out. 

The mechanic has diagnosed the clunk on front driver side as a wishbone issue,. He got it to cut out while hard braking so this is being investigated fully early next week. 

 @Pistolpete1, thanks for the reply, it would seem the revs are dropping too far according to the garage guy,  so hopefully when fully investigated all this will be rectified.

 

thanks

[pistolpete1]

I'd be interested in his conclusions! I forgot to mention that it cut out more,  and had a more fluctuating rev counter when using the clutch, when using standard petrol.

Since using Tesco Momentum it has rarely cut out, which is why I never investigated it further.

[Htpearg0]

Not sure what the mechanics of the induction system are hear but I had a vauxhall which had a throttle body and it contained an idle valeve which bypassed the butter fly. This would ocasionall stick causing the car to cut out . A clean with carb cleaner would cure it