Electronics - Can engine shutting down while driving!

[Fiestaki]

This is going to be a long post. If you are willing to offer your advice, and it ends up being the solution to the problem, I will send you €25 as a "thank you" gift via PayPal. I mean it.



Ford Fiesta Ecoboost 1.0 (100 bhp), first registration September 2017, manual transmission, engine built in Cologne/Germany engine plant. Start/Stop button, so no key-turning.

I bought the car second-hand. First owner was leasing the car for four years and then purchased it himself. All servicing/maintenance is well-documented.


I left the car standing for a month while on holiday. When I got back, the car wouldn't start. The road assistance came by, jump started the battery and the car worked fine. They ran a test on the battery and it showed that the battery life/quality was at 95%, almost like brand new. Drove the car without any issues for 5 months.


Left the car standing again while away, for a total of five weeks. When I got back, same problem. The road assistance came by, tried the same method, but the battery was dead. They would charge it on the spot for a few minutes and the battery would immediately empty within one minute. They had no idea how the battery could die within five weeks, so they assumed something was draining the battery while the car was standing still.


New battery was installed by an expert. Tried the 75mAh battery, the car wouldn't start, and for the first time ever, a buzzing sound could be heard from the fuse box. Tried a 70mAh battery, same issues. Tried a 65mAh battery, the issue was resolved. The car started immediately, and no buzzing sound coming from the fuse box. All batteries tested were brand new.


The next day, the car wouldn't start. Buzzing sound coming from the fuse box when trying to turn the engine on. Road assistance came by, they sprayed a lot of "contact cleaner" in the fuse box, the car managed to start right after that.


Then, less than 5 minutes later, the real issues started.. The car, for the first time ever, started shutting down while driving it (around 30km/h). The engine would shut down, the electronics were still on, and a message would come up on the dashboard saying "engine shut down". The buzzing sound came back. The car would shut down while idle or while driving, more than 7 times within a 10-minute period. Road assistance came by again. Sprayed a ton of contact cleaner into the fuse box, and the car started immediately and was able to drive.



Took it straight to the Ford dealer/garage. They said that they couldn't read the car computer errors because of a faulty "smart data link". They replaced it (brand new, €87), and deleted all the errors. Called me to pick the car up, they insisted it was fixed. As soon as I drove off the dealership, the car shut down within 5 minutes. Again, driving around town/urban environment at 30km/h. The car wouldn't even start at this point. Important info: the car engine would turn on and/or the dashboard would turn on when pressing the clutch, without pressing on the start/stop button. Never happened before, no idea how the clutch could affect the electronics/dashboard/car engine. The car had to be towed to the Ford dealership.



They called a few days later saying they found the problem. They explained that there is an electronics box of some sort, located above the left front seat (driver seat, in this particular car). There is a cable running from that box through the column on the side of the windshield going to the fuse box or the car computer, they weren't sure. They said this cable was a bit "loose" and they screwed it tight, so the issue is resolved. I asked them to drive the car extensively to make sure the issue is indeed gone, they said they drove it both on the highway as well as through some backroads (I checked the km, indeed, they must have drove the car for about 80km).



I drove the car home, no issues. Then 48 hours later, I attempted to turn the engine on, it did, and it shut down after a few seconds. Buzzing sound, dashboard lighting up, and the rev meter/needle climbing to 1,500 RPM while the engine was off.



At this point it is clear that the guys at the dealership have no clue what the issue may be.



If you read this far, thank you. If you've got any advice to share, please do. The reward stands (first person to identify the issue correctly).

 

[Handy Andy]

There are several fronts here, so take this as an advice, not as repair orders.

Three different times the Battery had or needed to be jump started - on every occasion they check and even replaced one battery. Never checked the wiring, cabling or other conditions of the battery tray or what is under it - being a main artery of electrical power, any acid that spilled from the battery tray can leak onto these connectors and wires causing erratic operation.

So remove the battery, tray and inspect the Red Connector (Battery Junction Block) and make sure all these different bolted on adapters are clean so they can make the best connections and keep the system operational - this includes the multi-tap black section of this block where the EPAS, MAIN and STARTER/ALTERNATOR electrical bolt to the block.

While battery is removed, inspect and check the connectors- their swivel arms - make sure the wires are not exposed - corroded or otherwise damaged - even pinched in two - because of the battery or it's box shifting weight and crushing the harness to itself causing shorts - corrosive acids from a leaky battery can also accelerate the condition.

Kick panel on both sides, hide and protect harnesses and connectors within them from causing shorts or getting damaged, you can remove these kick panels to find, locate and inspect where the Dealership (if they were true to their word) looked and worked on to diagnose the problems they thought they fixed.

Lastly - even a dropped keyfob can get damaged by the jolt so a spare keyfob or fresh battery replacements or similar may help in diagnosing a starting condition along with the buzzing - which to me sounds like a relay "bounce" caused by faulty wiring onto the relay or the Alternator and Starter cable needs to have its points of contacts inspect and tightened - a Starter solenoid on the Starter itself can fail and cause the Alternator to be left out of the loop and unable to recharge the battery - but you can see this by observation of dimming headlights and unable to use the climate controls due to it drains the battery faster and faster because the alternator can't feed power it has (and can send to the car but it only see itself as a voltage load so it thinks everything up to the break in the wiring is ok so the ALT light stays off) back into the system - so the Alternator may be ok, the wiring to the Starter and Alternator may not be - so look and investigate.

When I say investigate, inspect, test with Ohmmeters - Circuit Testers using lamps - check for current and power - locate the fuses and look for broken tabs and corroded leads on those fuses - if you can't do this by yourself, get someone alongside you that can to help you track this intermittent connection problem (or problems) down.

You said you went camping (vacation) - an animal can damage the car just by trying to live where its warm, by the engine so you may also have that condition to contend with.