Limp Mode, Fuel Leak, Burning Smell, & Neutral Tow

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mhExped

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Our '18 Expedition Limited went into limp mode today while my wife was driving to pick the kids up from school. After parking (post limp mode) to retrieve one of the kids, the car wouldn't start again. It cranked, but wouldn't turn over.

When I first arrived on scene, I smelled a faint odor of fuel and melting/burning. Faint, but noticeable.

The next few hours were spent waiting for the tow, then working with the tow operator, our local Ford service center, and corporate Ford trying to figure out how to get this car into neutral for towing without the engine running. This was a big mystery to everyone apparently.

Ultimately, we got the engine running quite by accident, I think. There's a "brake-shift interlock access slot" hidden in the center console. With the engine off, it didn't matter how we pressed this button, we were NEVER able to shift from Park to Neutral. Nor were we able to get the associated indicator lights to flash on the display.

As a last ditch effort, I tried depressing the button in the slot and trying to start the car simultaneously and, despite having tried to start numerous times/methods before and failing, the vehicle started, after a series of kinds strange steps. I can't remember them all, but it was definitely not a normal start. The one thing about it I do recall is that a message like "drive mode not available" flashed on the screen.

The other peculiar thing was when I turned the car off after this strange start. It also was a peculiar shut-off experience, most notably the parking brake automatically engaged when the engine shut off.

In any case, after finally getting the car pulled onto the flatbed for towing, we noticed a flow of fuel had dripped down from the underside of the vehicle and made a small stream of fuel down to the back of the tow bed. Obviously quite concerning given the series of events that led up to this.

Anyone experience anything similar to any of these events and arrive at a conclusive diagnosis and fix for any/all of it? I always like to have additional thoughts/questions to throw at the dealer in case they come back to me with the patented "there's no error codes, can't reproduce, it's 'normal'" lines. Can't imagine they'd feed me those lines on this one, but you never know. :)
 

FlyBry

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MH, please keep us informed about this, a serious situation that could have lead to injury. Leaking fuel from a 4th Gen is new to me, and I did a good job of reading the 4th Gen Forum for months. Will be interesting to read what the diagnosis is.
 

BMW2FORD

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Same here, please keep us posted. Was the fuel leak on the passenger side rear of the engine area? I noticed when checking things over the feed line from the tank connects to the high pressure pump and low pressure injector fuel rail in this area. The connection stood out to me since it looked to have a zip tie as a safety back up installed that looked factory.
 
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mhExped

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Was the fuel leak on the passenger side rear of the engine area?
I only got a brief look before the tow pulled away. The only thing I could tell was the fuel was dripping from the exhaust system just in front of the passenger-rear tire. I've circled that area in the attached diagram. But, that's just where it was dripping from the car to the tow bed, no clue where the actual origin was.

I started wondering if the fuel was excess from the failed starts? Flooding the engine? Scary that it could find its way to readily to the (potentially very hot) exhaust system components. I don't know enough about these cars to know if this should/should not happen in the case of failed starts.

Meanwhile, it looks like the dealer has started diagnosing the car this morning. Will definitely post the results once I hear something.
 

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Fastcar

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There is/was a small hole at the bottom rear of the muffler for condensation to weep out. If you had a stuck injector and it was dumping fuel, the fuel could have passed by an open valve and into the exhaust.

I had a stuck float on a holley 850 back in the day and it created almost the same scenario. You might want to have them change the oil as you probably have a load of gas in it or at least check the level or the viscosity before starting the engine.
 

Fizzy

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The initial problem sounds electrical to me. Do you park in an area where rodents could be accessing the bay?
 
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mhExped

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Just received word from the dealer...

Cause of the fuel leakage is exactly as @Fastcar suggested: Stuck open fuel injector (cylinder 6 to be specific). Good call @Fastcar! (I relayed them your comments, btw. So, thank you very much for throwing it out there.)

As to whether or not the stuck open fuel injector was the cause of going into limp mode in the first place vs a biproduct of all the failed starts thereafter, dealer says they won't be able comment on that until they're further along in the work to resolve the stuck injector.
 

FlyBry

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Wow! How common is a stuck injector on a Gen 4? Hence the safety measure of going into Limp Home/Safe Mode.
 

Fastcar

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Just received word from the dealer...

Cause of the fuel leakage is exactly as @Fastcar suggested: Stuck open fuel injector (cylinder 6 to be specific). Good call @Fastcar! (I relayed them your comments, btw. So, thank you very much for throwing it out there.)

As to whether or not the stuck open fuel injector was the cause of going into limp mode in the first place vs a biproduct of all the failed starts thereafter, dealer says they won't be able comment on that until they're further along in the work to resolve the stuck injector.
Glad it worked out for you. A couple of questions though. How many miles on it? Has the fuel filter been changed prior to this?
I'd strongly suggest you get a copy of the repair order in case the gas has gotten into the oil. If there is a lot of it you could suffer premature bearing failure. Thinking about it I'm surprised you didn't lock up the engine.
 

BMW2FORD

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Wow, amazing if there is no other damage and that it didn't lock up or fuel wash the cylinder wall and damage the engine. When you posted this, I thought it was an external leak but to send that much fuel through the exhaust that it leaked out the muffler is a lot. I agree with Fastcar, at least an oil change is needed besides the injector. Buy some lotto tickets if all it needs is an injector and oil change!!! Can you post back the part number they replace? I'm curios if this was a direct or port injector (these engines have 2x per cylinder and are very different than each other).
 
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mhExped

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How many miles on it? Has the fuel filter been changed prior to this?
Just under 24k miles. Off the top of my head I can't recall if the fuel filter has been changed. Why do you ask?

Thank you for all the suggestions. I'm making a list of talking points for further conversations with the dealer.
 

Fastcar

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Just under 24k miles. Off the top of my head I can't recall if the fuel filter has been changed. Why do you ask?

Thank you for all the suggestions. I'm making a list of talking points for further conversations with the dealer.
Just thinking about possible causes of the failure. Stay on the dealer as to the fuel dilution of the oil. You were pushing a lot to have it out the muffler. Ask the dealer to put in writing that no internal damage or premature wear occurred due to faulty injector.
I just reread your initial post. You said that after a couple of hours it did start. The plugs may have been fouled with fuel that dissipated over time. You may have more that one injector messing up.
 
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mhExped

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You said that after a couple of hours it did start.
More clarity on that...

- My wife said she only tried starting it 1x.
- I arrived on scene within about 30-40 min's. I smelled faint fuel odor (and slight burning/melting smell) at that time when standing near back of car.
- Tow truck arrived about 1 hour after that.
- Tow driver tried starting car 2-3 times.
- Next 1-2 hours were spent trying to figure out how to get the car into neutral without engine running (manual, dealer, and corporate Ford were all equally unhelpful). Ultimately, we wasted a bunch of time here believing the "brake-shift interlock" could help, but it turns out that's only helpful if the car is running.
- Tow driver then has me try to start the car about 3-4 times more while he has a battery jump connected.
- Immediately after that, I pressed and held the "brake-shift interlock" while trying to start and the car started (albeit with the strangest startup sequence I've heard from the car and with the "drive mode unavailable" message appearing on-dash).
- After that, I shifted into neutral and the tow driver pulled the car onto the bed.
- When he was about to drive away is when we noticed the leaking fuel.

So, really, the car sat for quite awhile without any start attempts, then had a series of start attempts real close together, before ultimately holding in the "brake-shift interlock" button resulted in a successful start.

I don't think it's by design that the "brake-shift interlock" aided the car in getting started, but I can't help but wonder if it was more than coincidence? Maybe holding that button in messed with the computer in a way that it was willing to start?

EDIT: So, when it finally started, it would have been the most flooded with fuel it had been.
 

Fastcar

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More clarity on that...

- My wife said she only tried starting it 1x.
- I arrived on scene within about 30-40 min's. I smelled faint fuel odor (and slight burning/melting smell) at that time when standing near back of car.
- Tow truck arrived about 1 hour after that.
- Tow driver tried starting car 2-3 times.
- Next 1-2 hours were spent trying to figure out how to get the car into neutral without engine running (manual, dealer, and corporate Ford were all equally unhelpful). Ultimately, we wasted a bunch of time here believing the "brake-shift interlock" could help, but it turns out that's only helpful if the car is running.
- Tow driver then has me try to start the car about 3-4 times more while he has a battery jump connected.
- Immediately after that, I pressed and held the "brake-shift interlock" while trying to start and the car started (albeit with the strangest startup sequence I've heard from the car and with the "drive mode unavailable" message appearing on-dash).
- After that, I shifted into neutral and the tow driver pulled the car onto the bed.
- When he was about to drive away is when we noticed the leaking fuel.

So, really, the car sat for quite awhile without any start attempts, then had a series of start attempts real close together, before ultimately holding in the "brake-shift interlock" button resulted in a successful start.

I don't think it's by design that the "brake-shift interlock" aided the car in getting started, but I can't help but wonder if it was more than coincidence? Maybe holding that button in messed with the computer in a way that it was willing to start?

EDIT: So, when it finally started, it would have been the most flooded with fuel it had been.
I'm not up on all the function of the brake interlock other that you can't start it unless the brake is depressed. With all these attempts to start was the engine turning over and not starting or was sputtering and not running or doing nothing at all, no noise? Did you at any time get sorta of a half a revolution and it stopped?
Sorry, don't mean to interrogate you just trying to ascertain whether the engine locked and then fired after the fuel drained down.
 
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mhExped

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...was the engine turning over and not starting or was sputtering and not running or doing nothing at all, no noise?
I would describe it as "crank no-start" as shown in this video at around 2:40: https://www.youtube.com/watch?v=TjK31lqJWkA

The amount of time spent cranking on each failed start attempt was consistent. Something like 5-10 seconds (I didn't pay close attention, but could tell it was some default timeout programmed in).
 

Fastcar

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I would describe it as "crank no-start" as shown in this video at around 2:40: https://www.youtube.com/watch?v=TjK31lqJWkA

The amount of time spent cranking on each failed start attempt was consistent. Something like 5-10 seconds (I didn't pay close attention, but could tell it was some default timeout programmed in).
Okay. As you are cranking that engine over you are dumping fuel into the cylinders. That fuel will work around the rings and end up in the oil as it is not being fired. I'd ask the dealer to check the plugs as they are probably fouled, so you'll at least get new plugs under warranty if they gas soaked or fouled.
 

Zig10

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I wouldn't sweat any potential internal damage based on some fuel in the oil. There are HO outboard motors that "make oil" with ring blowby that gain 1/2 quart over a season and don't see any issues. I'm not saying it's good practice, but you obviously didn't drive it very far (if at all) with that bad injector hung open and the car in limp mode. Once they get it all put back together change the oil and you should be in good shape.

Look at it this way - you're way better off to have an injector stick open than to have one clog and run lean on a forced induction motor. Had that happen on a previous supercharged vehicle and had a nice detonation event that cracked the #4 piston.

Hopefully they get you fixed up and back on the road in short order.
 

FlyBry

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Interesting. Rockauto shows the fuel filter for the 2018 & 19, but no listing for the 20 or 21.
 
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