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.
 
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