[sputnik]

Why can I drive an Insight backwards without giving the car any fuel?

It involves keeping the clutch partially engaged and I suspect the car is getting power somehow (the battery?, the electric motor?). All but one of our cars have been MT, yet I can't think of any with such a pronounced ability to self-propel.

Is this a general characteristic of all manual transmissions that I'm just now noticing, or is it particular to the Insight? Is it related to the Insight's ability to slow down in gear to a near stop and still have a live engine?

Apologies if the question is wacky, but I've been wondering about this for months. Thank-you for any info.

Respectfully,

 

[b1shmu63]

Since you said respectfully.

The Insight has very little rolling friction compared to other cars and its IMA and fuel system try to keep the motor from stalling when it is idling. The motor actually increases its power if it senses a load in order to keep the RPM the same. When you slip the clutch you allow a portion of the engines power to be delivered to the wheels, which in the case of the Insight is sufficient to move the car.

I have never owned a car before where I had to use the handbrake when parked! A tiny slope or a strong wind and away she goes. :shock:

This is a good thing. all cars should be this way.

If an automatic equipped vehicle pulls forward significantly with no foot on the gas, this is a bad thing. It could mean the engine is idling too fast or the torque converter is missadjusted. Under these conditions the automatic vehicle is wasting gasoline and generating excess pollution with zero payback.

If an automatic vehicle sitting in park suddenly drives forward and destroys your garage door this is a recall thing.

 

[Insightful Trekker]

Kip's good point about weight and rolling resistance are the keys.

Most cars are similar in behavior. The reverse gear ratio is not designed for HIGH engine RPM use. You don't need to go 50 MPH in reverse and probably can't control the car without crashing if you tried.

Insight gear ratio specifications (MT)

1st gear ratio 3.461
2nd 1.750
Reverse 3.208

The reverse gear's ratio is set in mind for use with engine speeds at idle and slightly above. And to be sufficent to move the car without stalling. A lower ratio will only lug the engine in the speed range most commonly used for backing.

HTH!

 

[ethicalpaul]

If an automatic equipped vehicle pulls forward with no foot on the gas, this is a bad thing. It means the engine is idling too fast or the torque converter is missadjusted.

Really? I've never driven an automatic that didn't require a foot on the brake to keep it still at idle.

 

[Dgate]

There are a lot of variables here,some automatics pull when drive is engaged which is normal and aides in manuevering especially when using the left foot brake technique or waiting on an incline when right foot braking is used.Other automatics such as a tiptronic type do not pull when engaged and can roll back on inclines if the brake is not used dilligently.Some CVT automatics do not pull and others do, so not all automatics can be described as having the same characterisitics.
Suffice to say all equipped with torgue convertors want to pull when drive is engaged and may pull excessively if the idle is too high.

DGate

 

[b1shmu63]

Thanks Paul, I've edited my previous post. I have been driving standard since 1980.

While test driving new automatics (for my brother) last weekend the cars we tried did not seem to pull forward, at least not noticeably.