Q: The engine is restarting for no apparent reason. What is happening?

A: If your Insight's gasoline engine is restarting for no apparent reason, it is probably due to one of the following reasons:

• The computer thinks you are about to accelerate - When decelerating, after the gasoline engine has stopped, if you release the brakes before coming to a complete stop, the engine may restart. Even though you may just plan on coasting before braking further, when you release the brake pedal the computer thinks you are about to accelerate again, and this is why the engine is restarted. If you don't want the engine to restart in this situation, simply keep your foot on the clutch pedal when you release the brakes. This tells the computer that you don't plan on accelerating immediately, and so it won't restart the engine.

• Master brake cylinder pressure is too low - The power brakes in the Insight, like most cars, receive their power assist from the vacuum created in the intake manifold by the engine. In simple terms, if you apply and release the brakes a number of times with the engine not running, you will begin to deplete the reserve of "power". The Insight's computer is smart enough to sense this situation and automatically restart the engine to provide further power assistance to the brakes when needed. You can minimize unnecessary running of the gas engine by using fewer & longer brake applications, rather than "pumping" the brakes when in idle stop mode.

Other conditions where you should also expect the internal combustion engine to automatically restart are:

• The battery's remaining charge becomes low (e.g. you've been stopped with the key in the "on" position a long time with a lot of accessories running)
• You shift from neutral into any gear (with the clutch pedal pressed)
• You press the gas pedal (with clutch pedal pressed or transmission in neutral)

Q: My battery charge level suddenly went to zero. What happened?

A: This is normal behavior. Depending on your driving pattern, you may see this often, rarely or never. The charge in the battery has not suddenly gone away, the gauge has just "corrected" to accurately reflect the amount of available charge. The more assist and partial re-charging that has taken place since the gauge last read fully charged, the more likely you are to see this.

Technical explanation:

Unlike a fuel tank where the amount of remaining fuel can be physically measured, there is no direct way to determine the battery's charge level. Instead, the best the battery gauge can show is an estimate. This estimate is based on the following measurements:

A. The amount of current that has "entered" or "left" the battery since it was last fully charged or fully discharged,

B. Measurements from the 10 battery voltage sensors, and

C. Measurements from the 4 battery temperature sensors.

The resulting battery charge estimate tends to be remarkably accurate. However, as the car is driven, this estimate will drift from the actual amount of charge available. Since the measurements of current are cumulative from the last time the battery was deemed fully charged or fully discharged, the more the battery has been used since it was last entirely full or empty, the greater this drift will tend to be.

When this drift becomes great enough, the car will detect that its measurements from current, voltage and temperature sensors don't agree with one another and determine that there is no longer any further available charge. When this happens the gauge will correct itself.

The typical scenario:

Common situations where you may see this correction is shortly after you've been climbing a long hill, or after you've done a fair bit of full-throttle acceleration. Prior to correcting itself, the gauge will still show some charge remaining. When the correction happens, the gauge may fall instantly to zero, or you may notice it stepping downwards over a period of several seconds or longer, before falling all the way to zero. You may also notice situations where the gauge indicated some charge left prior to turning off the car, but shows zero charge the next time you start it up. This is because the IMA system remains active and battery charge measurements continue for several seconds after the car is turned off.

After the gauge correction, the car will behave as it normally does when the charge is very low. Specifically, auto idle stop will not take place, you will see the gauge showing partial charge when idling, decelerating or cruising at a constant speed. Also, no electric assist will be available for a few minutes until the battery has some charge available.

If anyone ever questions whether the Insight's electric motor really makes a significant contribution to performance, driving with no charge available illustrates clearly that it does. You can still get around perfectly fine with no charge (though you may notice you need to give it more gas that you normally have to when starting from a stop in the 5 speed Insight), but it lacks a lot of its normal fun-to-drive character until a bit of battery charge is restored.

Note: You should also be aware that like many fuel gauges, the battery level gauge is non-linear. It is designed so that the top half of the gauge represents significantly more than half of the overall battery capacity. This makes small changes in available charge much more evident when the charge is low, when charge level becomes more relevant.

Also Note: To maximize battery life, the IMA system maintains the NiMH battery pack between 20% and 80% of its rated charge level. As such, the system considers the battery fully charged at 80%, which corresponds to the very top of the battery level gauge. Likewise, it considers the battery fully discharged at 20%, which corresponds to the very bottom of the battery level gauge.

Q: I occasionally notice a slight unexpected surge in engine power. What is this?

A: From time to time some owners notice a slight unexpected engine surge that doesn't correspond to any additional pressure on the gas pedal.

What they are most likely noticing is the computer temporarily switching the engine to a richer air-fuel ratio to purge the lean-burn NOx catalyst. This mode will last for about 10 - 15 seconds.

One of the things that makes the Insight's gasoline engine so efficient is that it can operate at a very lean air-fuel ratio. The ratio of gasoline to air can be as low as 22:1, as compared to the normal (stoichiometric) ratio of 14.7:1.

This lean burn operation has the benefit of reducing fuel consumption, CO2, CO and hydrocarbon emissions. The disadvantage is higher NOx emissions. To keep NOx emissions below ULEV levels, the Insight uses a special lean-burn NOx catalyst. During lean-burn mode, the additional NOx and oxygen present in the exhaust is catalyzed and stored as nitrogen dioxide. During later non-lean-burn operation, this is then catalyzed to harmless nitrogen gas, carbon dioxide and water vapor.

If the engine has been running in lean-burn mode for an extended period of time, the lean-burn NOx catalyst may become saturated (full). The NOx catalyst has a sensor that tells the engine management computer when the catalyst is saturated. The computer will then temporarily richen the air-fuel mixture to purge (empty) the NOx catalyst.

When the computer adds more fuel, this will result in a slight surge in power, and a corresponding movement of the FCD display. This is probably what people are noticing.

Something to keep in mind is that the engine only runs in lean-burn mode under light load conditions. This has a couple implications:

1. If you don't drive for relatively long periods of time at a constant cruising speed, you may never saturate the NOx catalyst, and so may never notice this engine surge for seemingly no reason.

2. When you're cruising at a constant speed and then decide to accelerate, you can apply slight throttle pressure without taking the engine out of lean burn mode. However, if you apply slightly more pressure, the computer will richen the mixture, and you'll again feel a slight surge of power.

Some people have attributed this surge to the VTEC-E system, but in most cases they're probably mistaken. The VTEC-E system always turns on the second set of intake valves at a 2500 RPM, and turns them off at 2300 RPM, regardless of engine load. Also, if you watch closely, you'll notice that this surge of power doesn't necessarily correspond to the IMA assist. You will still notice, though, a slight jump on the FCD bar graph when the engine switches in to or out of lean burn mode.

Q: My downshift light never turns on. Is something wrong?

A: Probably not.

The downshift light only illuminates under high load conditions, when a lower gear is needed to maintain the current speed. Generally the only situation where you should expect this light to come on is when driving in hilly/mountainous areas, while driving up a steep incline in fourth or fifth gear. The light will illuminate to request a downshift to fourth or sometimes third.

The downshift light doesn't illuminate to tell you that you're going too slowly for the current gear.

Many Insight owners who don't live in mountainous areas may never see the downshift light come on.

Q: Will I get stuck at traffic lights due to magnetic sensor not being triggered by the Aluminum-bodied Insight?

A: No. The sensors that trigger some traffic lights are sometimes referred to as "magnetic", but they're actually electromagnetic, measuring a variance in EMF when a conductor (rather than a ferrous material) passes through the field. Thus, aluminum should work as well as iron.

I'm having trouble closing my hood

Some owners have found the Insight's hood to be a little difficult to get latched properly. This is the approach that Geoff Shepherd suggests as a simple & foolproof method:

1. Make sure the latch release handle inside is pushed back to its resting position
2. Put the hood down
3. With the palm of your hand, firmly press on the Honda logo to latch the hood fully
4. Enjoy the controlled latching sound. Doesn't that sound so much better than dropping the hood?

I have found that the Honda logo is right over the hood latch mechanism and
seems to be able to take some pressure without deforming the aluminum skin.
You car may be different, so proceed with caution.