From: brooks@mcnc.org (Ted Brooks)
Subject: Re: stuck carb, airborne
Organization: MCNC Center for Microelectronics, RTP, NC
Date: Wed, 23 Dec 1992 14:24:51 GMT

In article <n12cct@ofa123.fidonet.org> Larry.Mc.Donald@ofa123.fidonet.org writes:
> zm@cbnewsb.cb.att.com 
>   
>   (Zafer Mehmood)
>
>> Whenever I read stories about runaway cars with stuck throttle 
>> plate/cable or cruise mechanisms, I wonder why the transmission cannot
>> be shifted into neutral to disengage the engine from the drive-train.
>> Yes, the engine can over-rev causing damage but that's a cheap price
>> to pay compared to the risk of collision and bodily injury. In a
>> couple of automatics that I've tried, I was able to shift into neutral
>> even while accelerating. Manual transmissions, on the other hand won't
>> shift into neutral while accelerating (at least not easily), but then
>> you can use the clutch to disengage the engine from the transmission.
>
>> Aside from the driver panicking and not having the presence of mind,
>> is there a reason why this can not be done? Am I missing something?
>
>   Other than pieces of the block getting under the tires and 
>puncturing them, no, no reason. A better solution that doesn't 
>cause irrepairable engine damage is to just turn the car off. I 
>had a Ford Maverick get it's throttle stuck on the freeway and I 
>was able to get it off the freeway and to a parking lot by 
>regulating it's speed by turning it on and off. 
>
Bet you got plenty of backfiring in the exhaust. Still, that's a lot
better than having a wreck or blowing the engine.

One of the classic stuck throttle syndrome cars were the full size Chevys
of the mid '60s. As I recall from an automotive safety class I took years
ago, the scenario went like this. Someone with a hot small block V8 would
stomp on the gas. These cars had a bunch of bad motor mounts, so the one
motor mount would break. The broken motor mount allowed the engine to shift
position.  This would jam the throttle linkage, and also cause
the automatic transmission linkage to bind. If the motor rocked far enough,
the power steering hoses would break too, which is real bad if you happened
to be showing off by taking a fast curve. So now you've got a car with a hot
engine stuck at full throttle, stuck in the passing gear, and no power steering
assist. Two reasons one might think not turn off the ignition. One, you know
you're screwed and you're filling your pants while trying to maintain 
control :-() - in other words, panic. Two, you've got both hands on the
wheel trying to manhandle the failed power steering.

GM caught a lot of flak for their bad motor mounts, and didn't win any
friends when the recall fix was adding a chain between the block and frame
instead of replacing the motor mounts.

 
Ted Brooks
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