Rental Ford Fiesta Accelerates After Accident

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gathermewool

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The short: I was rear-ended and pushed into the truck in front of me. Following impact, the Fiesta began to accelerate. The brakes held, but I had to slam the transmission into to Park and kill the engine to stop the acceleration and subsequent engine rev.

The long version:

I'm on travel and have a Ford Fiesta as a rental car. On my way back to the hotel I'm staying at this evening there was a lot of traffic and people driving pretty wildly, IMO. Well, I saw it coming and was luckily able to stop without incident when the guy in front of me (and the guys in front of him) literally locked it up. Unfortunately, the lady behind me took her eyes off the road to check out the accident not 50 yards back (according to the cop, that accident was a result of a husband rear-ending his wife. Insert joke here) and plowed right into me.

I don't know how fast she was going , but I recall being stopped and feeling that awful feeling of helplessness as I saw her coming up in my rear-view way too fast.

After the impact I heard an engine revving and some vibration and thought, "oh, no, the person in the car behind me hit the wrong pedal in a panic!" After what seemed like only a few seconds, the guy in front of me, who's bumper I was smushed into, moved forward and off to the shoulder. My foot was only lightly on the brake at this point and my car began to move forward with the truck in front of me.

Part of my brain thought I was still being pushed, while the other considered whether I was wedged hard enough into the truck's bumper that I was actually being pulled. After what felt like an eternity, but was probably only 10 or less seconds (from time of impact) I looked down and realized that the tach was at ~2500 RPM. I was able to stop forward motion with a firm stomp on the brakes, and then killed it by shifting to Park and concurrently turning off the ignition before the engine was even able to rev any higher.

I was just telling everyone how impressed I was with the little Fiesta, but now, after this incident, I don't know what to think. The observed behavior is unacceptable. I worry what might happen if some one was in the same situation and didn't react as I did. Based on what I observed, the realistic worst cases are that without operator interaction, the car would accelerate into the truck in front again as it pulled away, or that it would cruise into the adjacent lane and hit someone else or be hit by some one else, should the driver fail to hit the brakes due to shock. The same could be possible without th operator maintaining the brake depressed if the vehicle idled forward, but would be made much worse in this case, where it actually accelerated.

Any ideas why this would occur?
 
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First of all, glad that you survived it unscathed.

IMO, at least for now, a malfunction with electronic throttle control a.k.a. drive by wire.
 
I expected the engine to die, honestly. My brain almost didn't comprehend what was happening - I responded on instinct alone.
 
Originally Posted By: gathermewool
After what felt like an eternity, but was probably only 10 or less seconds (from time of impact) I looked down and realized that the tach was at ~2500 RPM. I was able to stop forward motion with a firm stomp on the brakes, and then killed it by shifting to Park and concurrently turning off the ignition before the engine was even able to rev any higher.


Either what you did, or shifting to Neutral and braking.
 
Originally Posted By: tswm
First of all, glad that you survived it unscathed.

IMO, at least for now, a malfunction with electronic throttle control a.k.a. drive by wire.

This sounds likely enough. When a drive-by-wire throttle body loses electrical input it doesn't go to full closed. Instead, it goes to a position that is open just enough to drive up a small incline and get out of the way of traffic, but not open enough to overheat the brakes. This is a safety feature.

I'm a bit surprised this new Fiesta lacks the infamous Ford inertia switch that stalls the engine after a hard jolt such as a nasty pothole hit.
 
Originally Posted By: yonyon
When a drive-by-wire throttle body loses electrical input it doesn't go to full closed. Instead, it goes to a position that is open just enough to drive up a small incline and get out of the way of traffic, but not open enough to overheat the brakes. This is a safety feature.


What you say makes a lot of sense to me. Thank you for the insight.
 
I have said it before....with drive by wire we are risking our lives and futures to a computer to decide what is best for us...no throttle or "full" throttle,we have no input.Just wait until hitmen figure out how to remotely program a DBW system to eliminate those they want done away with.No sir,no drive by wire here... I want some say in how I die,or live.
 
You rearended a truck. 99.99% sure it had a trailer hitch installed, and I bet you were impaled on it.

28.gif


I wonder if the throttle pedal got jarred, stuck in a spot and rev'd up the motor. That or maybe the throttle position sensor in the throttle body (or whatever flap is on the intake, it likely has a position sensor as feedback that the plate did open to x% after being requested) got jarred.

Were you able to drive away afterwards? Did the fault clear itself? If so it was probably just a Windows issue, and needed a reboot.
 
Originally Posted By: supton
You rearended a truck. 99.99% sure it had a trailer hitch installed, and I bet you were impaled on it.

28.gif


I wonder if the throttle pedal got jarred, stuck in a spot and rev'd up the motor. That or maybe the throttle position sensor in the throttle body (or whatever flap is on the intake, it likely has a position sensor as feedback that the plate did open to x% after being requested) got jarred.

Were you able to drive away afterwards? Did the fault clear itself? If so it was probably just a Windows issue, and needed a reboot.


Either way - hitch or not - that is definitely an issue to be reported to NHTSA.
 
Originally Posted By: yonyon
Originally Posted By: tswm
First of all, glad that you survived it unscathed.

IMO, at least for now, a malfunction with electronic throttle control a.k.a. drive by wire.

This sounds likely enough. When a drive-by-wire throttle body loses electrical input it doesn't go to full closed. Instead, it goes to a position that is open just enough to drive up a small incline and get out of the way of traffic, but not open enough to overheat the brakes. This is a safety feature.

I'm a bit surprised this new Fiesta lacks the infamous Ford inertia switch that stalls the engine after a hard jolt such as a nasty pothole hit.


They have the inertia switch.

In my experience, you don't have to get in an accident to trip them. I have tripped them on pot holes ...
 
Originally Posted By: Miller88
In my experience, you don't have to get in an accident to trip them. I have tripped them on pot holes ...


"Sorry, hun, let me re-start the engine, I just hit a manhole cover!"
 
Originally Posted By: Hokiefyd
Originally Posted By: Miller88
In my experience, you don't have to get in an accident to trip them. I have tripped them on pot holes ...


"Sorry, hun, let me re-start the engine, I just hit a manhole cover!"


I had that happen once in a very bad neighborhood!

Seems that after they get tripped once (either via accident or pot hole) they trip much easier.
 
Didn't they used to have the reset in the trunk? Want to say it was like a push-button breaker; had a friend with a Tempo and somehow I knew it could be that. [Wasn't, fuel pump died instead.]
 
Originally Posted By: supton
Didn't they used to have the reset in the trunk? Want to say it was like a push-button breaker; had a friend with a Tempo and somehow I knew it could be that. [Wasn't, fuel pump died instead.]


Yup. It was behind the trunk liner on my townie and in a similar location in my Mustang.
 
On my Focus it's by the passenger's right foot. No longer do you have to hop out in a bad neighborhood, open the trunk, pull back the liner and push the button! Just reach over and press it!
 
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