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My father was gifted a 1972 Buick Regal. I was asked to drive it on I-85 (interstate) During acceleration on the onramp, the cable controlling the throttle go

My father was gifted a 1972 Buick Regal. I was asked to drive it on I-85 (interstate) During acceleration on the onramp, the cable controlling the throttle got stuck and the gas was flowing into the carb and UA continued to occur. I was reaching speeds in excess of 100 MPH (160 Kmph). The brakes did nothing to slow me me down. My wife, driving adjacent to me in another vehicle, thought I was showboating or just being wreckless. I had to kill the engine with the key, slow down, and then crank the car, begin accelerating, then kill the engine to 'manage' the vehicle until I could get off the interstate. Terrifying ordeal.

tempnow987 4y ago
I was boating and same issue - broke to full throttle on a gas engine. So I just came flying in and killed engine. I could have restarted probably if needed. These things are almost always stoppable. Another boat had a diesel. This boat had serious flooding and I went over to help ($1M+ boat, owner had backed it hard into concrete pier and not noticed a transom crack that opened). Engine would not shut off (electrical all shorted out). That diesel engine was running full tilt almost totally submerged - was pretty impressive. Eventually someone got a mask and snorkel and dove to fuel cutoff before it ingested a bunch of water through air intake (which I'm sure would have stopped it). With diesels I always liked knowing where manual fuel cutoff was after that.
- moron4hire 4y ago
  A place I worked years ago was a manufacturer of industrial lifting cranes. They had a problem one particularly hot summer of the diesels in the cranes starting up in their own. These were massive engines. The block was bigger than my whole car. Terrifying watching one of them run away. They tended towards "violent, unscheduled disassembly" if they couldn't be shut down.
- hatsunearu 4y ago
  Hijacking (kinda): diesels are vulnerable to a phenomenon called "diesel runaway", where unintended fuel (for instance, engine oil leaks) seems into the intake/cylinder. The engine is controlled by how much fuel is injected, so if you just add an extra amount of fuel it will start increasing torque all on its own, and in the worst case, will cause unintended acceleration. Nowadays diesels actually come with throttle bodies for emissions reasons which I think also will serve a safety function against runaways.
  - sokoloff 4y ago
    A major part of diesel efficiency comes from a lack of a throttle plate. I’d be surprised if adding one was beneficial for emissions. Do you have any reference here? I couldn’t find one with a quick googling.
    - namibj 4y ago
      I'd guess too-lean combustion in idle is bad, and throttling the intake so that it starts out with reduced pressure and at the fixed compression ratio, won't reach as-high pressures (which waste power by some of the adiabatic heating coupling to the cylinder walls). Might only work on individual cylinders, as it seems like it'd easily prevent ignition, but still...
    - GeorgeWBasic 4y ago
      I don't know if it's for emissions reasons, and I doubt it does anything for emissions, but Volkswagen diesels have a throttle that's there to make engine shutoff much less shaky. It's called the anti-shudder valve, and it activates every time the engine is stopped, and it would stop a runaway diesel.
    - hatsunearu 4y ago
      https://www.team-bhp.com/forum/technical-stuff/188332-explained-why-diesel-engines-need-throttle-body-throttle-plate.html https://www.team-bhp.com/forum/technical-stuff/188332-explai... from what i understand it's mostly to have a control over the air fuel ratio.
      - gonzo 4y ago
        That’s what the injectors are for. It’s for emissions
        hatsunearu 4y ago
        what the heck are you talking about, if you're at partial throttle, by design a normal diesel has no control over how much air is entering the engine, so your only way of modulating torque is changing the injection. This means your air fuel ratio will be uncontrolled, which is bad for emissions.
WalterBright 4y ago
Happened to me once. I stuck my foot under the gas pedal and forced it back up. The throttle return spring is rather weak, and it doesn't take much to gum it up. A little force the other way will usually unstick it.
- kevin_thibedeau 4y ago
  That only fixes a stuck pedal. If its stuck at the other end you'll just slacken the cable.
  - WalterBright 4y ago
    pulling the pedal back pulls the cable, not slackening it.
    - hef19898 4y ago
      Vaccum leaks can do the same, in idle that is. My '82 Rover V8 has that attitude sometimes when it's hot and not a lot air gets to the engine (traffic jams and so). Needs some load to get revs down, ideally the engine get cooled down. Have to hunt the issue down. Apparently it can happen with carbs in general. I knoe people tgat had issues switching this engine off in the desert because the fuel in the carbs evaporated and continued to be pulled in the engine. Which was hot enough to to ignite it for a while...
      - WalterBright 4y ago
        Yeah, it's called run-on. Just let out the clutch and force a stall.
tomcam 4y ago
OK that’s a straight up nightmare. Really cool thinking under pressure.
Markoff 4y ago
Doesn't steering wheel get locked on some cars when you kill the engine? Seems switching to Neutral is safer option. EDIT: I read that on some cars you can have problem to change to Neutral without brake, so even if brake fails I guess your only option is slowly pull the emergency brake.
vikingerik 4y ago
In such cases, if you can't brake or release the throttle, one other out is to gear-shift into neutral. The result of slamming that power into neutral won't be great for the engine or transmission, but at least you'll be able to stop accelerating and coast to a stop.
- macintux 4y ago
  I recall riding with a friend who had an automatic, and his engine was racing at every stoplight (I don't recall the name of the hardware that's supposed to disengage the engine when the brake is fully applied, but clearly it was broken). So, he sat at every light with the brake pushed hard to the floor, trying to keep it from plunging into the intersection. As a long-time stick shift driver, I asked him why he didn't just shift it into neutral.
  - hatsunearu 4y ago
    uh what the fuck? why didn't he fix the damn car?
    - sokoloff 4y ago
      I suspect a lot of people find themself in a situation where driving a car with a mechanical problem is a sensible local optimum for some period of time. The statute of limitations has passed on all of my “she’ll be a’ight” endeavors, but they included having to manually apply throttle to keep the engine lit, driving on partial service brakes, driving without a working charging system, having to push start the car, reckoning speed by gear and RPM, and fueling based on ded reckoning with an INOP fuel gauge and odometer.
      - throwaway0a5e 4y ago
        The partial brakes is the only thing on that list I'd consider to be more than just an inconvenience. Obviously if you want to drive like a jerk you need the car to be in tip top shape so that you have the most freedom to make control inputs but if you just want to putt along and drive in a mild mannered way having a bunch of mechanical oddities that constrain what you can do isn't a big deal.
kemiller2002 4y ago
"Funny" enough, my family had a similar experience. My parents owned a 1984 Ford conversion van. On a family road trip, a squirrel got up into the engine and built a nest or something around the component which was used to control the amount of gas going into the engine (I don't remember the exact specifics), my dad had to shift it between drive and neutral until we could make it off the highway as well.

tempnow987 4y ago

I was boating and same issue - broke to full throttle on a gas engine. So I just came flying in and killed engine. I could have restarted probably if needed. These things are almost always stoppable. Another boat had a diesel. This boat had serious flooding and I went over to help ($1M+ boat, owner had backed it hard into concrete pier and not noticed a transom crack that opened). Engine would not shut off (electrical all shorted out). That diesel engine was running full tilt almost totally submerged - was pretty impressive. Eventually someone got a mask and snorkel and dove to fuel cutoff before it ingested a bunch of water through air intake (which I'm sure would have stopped it). With diesels I always liked knowing where manual fuel cutoff was after that.

moron4hire 4y ago
A place I worked years ago was a manufacturer of industrial lifting cranes. They had a problem one particularly hot summer of the diesels in the cranes starting up in their own. These were massive engines. The block was bigger than my whole car. Terrifying watching one of them run away. They tended towards "violent, unscheduled disassembly" if they couldn't be shut down.
hatsunearu 4y ago
Hijacking (kinda): diesels are vulnerable to a phenomenon called "diesel runaway", where unintended fuel (for instance, engine oil leaks) seems into the intake/cylinder. The engine is controlled by how much fuel is injected, so if you just add an extra amount of fuel it will start increasing torque all on its own, and in the worst case, will cause unintended acceleration. Nowadays diesels actually come with throttle bodies for emissions reasons which I think also will serve a safety function against runaways.
- sokoloff 4y ago
  A major part of diesel efficiency comes from a lack of a throttle plate. I’d be surprised if adding one was beneficial for emissions. Do you have any reference here? I couldn’t find one with a quick googling.
  - namibj 4y ago
    I'd guess too-lean combustion in idle is bad, and throttling the intake so that it starts out with reduced pressure and at the fixed compression ratio, won't reach as-high pressures (which waste power by some of the adiabatic heating coupling to the cylinder walls). Might only work on individual cylinders, as it seems like it'd easily prevent ignition, but still...
  - GeorgeWBasic 4y ago
    I don't know if it's for emissions reasons, and I doubt it does anything for emissions, but Volkswagen diesels have a throttle that's there to make engine shutoff much less shaky. It's called the anti-shudder valve, and it activates every time the engine is stopped, and it would stop a runaway diesel.
  - hatsunearu 4y ago
    https://www.team-bhp.com/forum/technical-stuff/188332-explained-why-diesel-engines-need-throttle-body-throttle-plate.html https://www.team-bhp.com/forum/technical-stuff/188332-explai... from what i understand it's mostly to have a control over the air fuel ratio.
    - gonzo 4y ago
      That’s what the injectors are for. It’s for emissions
      - hatsunearu 4y ago
        what the heck are you talking about, if you're at partial throttle, by design a normal diesel has no control over how much air is entering the engine, so your only way of modulating torque is changing the injection. This means your air fuel ratio will be uncontrolled, which is bad for emissions.

WalterBright 4y ago

Happened to me once. I stuck my foot under the gas pedal and forced it back up. The throttle return spring is rather weak, and it doesn't take much to gum it up. A little force the other way will usually unstick it.

kevin_thibedeau 4y ago
That only fixes a stuck pedal. If its stuck at the other end you'll just slacken the cable.
- WalterBright 4y ago
  pulling the pedal back pulls the cable, not slackening it.
  - hef19898 4y ago
    Vaccum leaks can do the same, in idle that is. My '82 Rover V8 has that attitude sometimes when it's hot and not a lot air gets to the engine (traffic jams and so). Needs some load to get revs down, ideally the engine get cooled down. Have to hunt the issue down. Apparently it can happen with carbs in general. I knoe people tgat had issues switching this engine off in the desert because the fuel in the carbs evaporated and continued to be pulled in the engine. Which was hot enough to to ignite it for a while...
    - WalterBright 4y ago
      Yeah, it's called run-on. Just let out the clutch and force a stall.

tomcam 4y ago

OK that’s a straight up nightmare. Really cool thinking under pressure.

Markoff 4y ago

Doesn't steering wheel get locked on some cars when you kill the engine? Seems switching to Neutral is safer option. EDIT: I read that on some cars you can have problem to change to Neutral without brake, so even if brake fails I guess your only option is slowly pull the emergency brake.

vikingerik 4y ago

In such cases, if you can't brake or release the throttle, one other out is to gear-shift into neutral. The result of slamming that power into neutral won't be great for the engine or transmission, but at least you'll be able to stop accelerating and coast to a stop.

macintux 4y ago
I recall riding with a friend who had an automatic, and his engine was racing at every stoplight (I don't recall the name of the hardware that's supposed to disengage the engine when the brake is fully applied, but clearly it was broken). So, he sat at every light with the brake pushed hard to the floor, trying to keep it from plunging into the intersection. As a long-time stick shift driver, I asked him why he didn't just shift it into neutral.
- hatsunearu 4y ago
  uh what the fuck? why didn't he fix the damn car?
  - sokoloff 4y ago
    I suspect a lot of people find themself in a situation where driving a car with a mechanical problem is a sensible local optimum for some period of time. The statute of limitations has passed on all of my “she’ll be a’ight” endeavors, but they included having to manually apply throttle to keep the engine lit, driving on partial service brakes, driving without a working charging system, having to push start the car, reckoning speed by gear and RPM, and fueling based on ded reckoning with an INOP fuel gauge and odometer.
    - throwaway0a5e 4y ago
      The partial brakes is the only thing on that list I'd consider to be more than just an inconvenience. Obviously if you want to drive like a jerk you need the car to be in tip top shape so that you have the most freedom to make control inputs but if you just want to putt along and drive in a mild mannered way having a bunch of mechanical oddities that constrain what you can do isn't a big deal.

kemiller2002 4y ago

"Funny" enough, my family had a similar experience. My parents owned a 1984 Ford conversion van. On a family road trip, a squirrel got up into the engine and built a nest or something around the component which was used to control the amount of gas going into the engine (I don't remember the exact specifics), my dad had to shift it between drive and neutral until we could make it off the highway as well.