1.0 Eco boost engines cuts out on auto strat stop

[Bertmort8]

Evening all.

Having an issue with my 18 plate 1.0l ecoboost.

It's very intermittent so doesn't happen every time.
Today the car was driving fine and then I pulled up to some lights and stopped. The auto stop kicked in and when the light turned green. As I dipped the clutch the car didnt respond.
Police car was behind me and fair play to them, they got out and give me a push. At that when the car was rolling, it then started up again.

Ive had the battery tested but came back at 99%.

Does anyone have any knowledge of this happening??

Cheers 👍

 

[Handy Andy]

Other possibilities include a change in the wiring harness, was any work done to the front of the car like any oil changes or technician once-over to check the engine?

Don't know if your vehicle ST is a Hybrid - that uses a 48V system....

Anyone change the floor mats or vacuum out the floorboards? A bump on the 3-rd pedal (clutch) or the brake light switch aspect can be changed by aggressive vacuuming. How? Dust and dirt - can affect the plunger on the "Starter" contact switch and prevent restart - especially when under the dash gets warmed up - cold weather changes the performance of the switches, can make them operate differently that when cold you get one result and no issues, but warmed up the thermal effects of temperature and change from cold to hot can alter the switch performance - it can get stuck at a mid-point position until you "play" with ir by moving the pedal so the action clears out the condition briefly.

There is (possible - depends on year) a second battery used to engage the starter relay - if the secondary battery gets weak, it won't always make the relay re-start switch engage fully so it won't make the starter kick it over. Again an HEV-type of line would use a secondary battery system. A smaller battery keeps the electronics powered until you release the brake or apply the gas - you mentioned clutch so to have Auto shut off engaging - leads me down the path of a dirty or unseated plunger giving you the fits due to the plungers' sticking or got dirty - preventing it from making the proper contact until you play with it.