Vehicle Operation

A slight lean towards the drivers side is normal. Conjecture on this subject has been wide and varied for many years, but nobody has quite been able to finger the exact reason. One theory is it was done so it would be easier to drive in a straight line on a one lane road, which rises in the middle to assist in drainage. The best theory thus far is that the lean is caused by the engine and driver being on the left-hand side. Nobody has complained thus far that it affects any part of the ride quality of the car, although a few people have commented that the right rear of the car tends to rattle a bit more. This may be because the lower left front tends to unload the right rear suspension slightly.

After 10+ years and if the lean is excessive, things to look at:

• suspension bushings are probably worn out, causing excessive lean.
• different brand/size tires
• spring snapped in half
• check the spring seat at the top of the strut tower. rubber spacer might have rotted

In general, normal idle for a DSM is 750 RPM. However, due to specifications for various components, an idle of 700-825 RPM displayed on your tachometer can be considered normal (in the absence of other symptoms). This specification applies to a fully warmed vehicle with all electrical accessories switched off (except Canadian vehicles, which have DRLs).

The car will have a higher idle under certain circumstances:

• The vehicle not fully warmed up (+0-500RPM, slowly falling)
• The A/C is on (+200-250RPM)
• The vehicle is not at a complete stop (+150-200RPM)

Note:

1G owners can expect 1.8L engines to idle at 800 RPM, while 2.0L (non-turbo and turbo) idle at 750 RPM. With the air conditioning on, automatics will drop to 650 RPM, while manuals will rise to 850 RPM.

2Gers will get 800 RPM out of their non-turbos, and 750 RPM from the 2.0 turbo and 2.4L engines. Again, this will rise to 850 RPM with the air conditioning on.

If your car does not idle exactly at these levels, or changes its idle slightly, occasionally or while driving, don't freak out. Few cars idle at precisely the designed level, owing to variations in climate and engine components. All of the above levels are rated at plus or minus 100 RPM, and the car will sometimes adjust the idle acording to driving conditions. If you don't have a problem with the car, leave the idle alone.

Some DSMers have problems with an unstable idle, or with their car being unable to maintain idle when coming to a stop. The first problem is a symptom of a badly set base idle, while the second in an indication of a broken speed sensor. Those with idle surge problems go here; those with cars that die at stoplights go here.

Most owners get around 20 MPG (11.75 L/100km). On-highway use typically results in 25 MPG (9.5 L/100 km).  These numbers vary a fair amount according to season, location, altitude, type of driving, state of modifications, age of various parts, and quality of gasoline used; non-turbo owners often have the edge here. Owners have reported 'normal' mileage on both new and used cars that vary from typical by as much as 10 MPG.

Mileage in the 12-13 MPG (18-20 L/100 km) sometimes reflects a problem with the car.  An old or failing oxygen sensor is a prime suspect, as this component senses the air/fuel mixture and, when bad (or even weak), can cause the ECU to supply more fuel than is necessary. According to Todd Day of Technomotive, even a slightly weak O2 sensor can knock 1-2 MPG off of the normal mileage. Since weak or dead oxygen sensors often do not trip the "Check Engine" light (see here for why), owners may not realize their O2 sensor is on the blink.

However, this is not always the case. Mileage can often be lower in the winter simply because of the widespread sale of oxygenated gasoline, which tends to lower fuel mileage. Cold weather also leads to increased idling and more congested traffic.

Another common problem occurs when upgraded downpipes are installed. Techs often forget to re-connect the ground strap from the original downpipe, leading to a poor ground for the oxygen sensor that can have the car running rich.

If you're really desparate, try replacing your thermostat - a poorly operating unit can keep the car thinking it's cold so it never leaves it's 'warm-up' mode, during which the ECU runs the car richer than normal.

Oil pressure is directly related to

• the ambient temperature
• the engine temperature
• the amount of oil in the engine
• the engine speed

When changing the oil you often end up with a slightly different amount of oil in the engine then you had previously.  Less oil means less oil pressure - add a little more oil and the pressure will rise.

Also, the oil pump is driven by an accessory belt. Operating the engine at higher speed runs the oil pump faster, raising oil pressure. Consequently, oil pressure is lowest when the car is idling (and hot), and will rise during cruising.

Normal oil pressure on these cars is between the Low and Mid mark when idling, and between the Mid and High marks when cruising. These marks, unfortunately, do not correspond to any known psi rating.

Limited testing by DSM owners with mechanical oil pressure gauges indicate that DSMs tend to have around 70-90 psi of oil pressure while cruising, and only 10-20 psi while idling. Cold starts can generate oil pressures of over 100 psi, a fact verified by the DSM manuals when discussing proper oil filter selection.

Consistently low oil pressure while driving could be an oil leak, or a bad oil pressure sending unit. Be careful.

The Last Word: Some DSMs just show low oil pressure, period. My car has shown low oil pressure for years, but nothing comes of it.

And, despite what some people have told me, oil pressure DOES depend - a little bit, at least - on the amount of oil. I've seen the oil pressure on my car go up by adding a bit more oil. There is a danger of overfilling the oil and causing oil "frothing", but I consider that a low-probability problem, whereas my car (and most DSMs, by now) does definitely leak and/or burn oil. Personally, I'd rather have a bit too much than not enough.

The oil light on the dash may come on under hard braking when your oil is low. Top up immediately.

Finally, the little connector that connects the oil pressure sender to the dash gauge can wear out and/or fall off. The gauge will show zero oil pressure and scare the bejeezus out of you, but the dash oil light doesn't light up. The sender is located between the oil filter and the wheel, under the car.

1990-1991 DSMs had pop-up headlights. The popup button raised the lights even if they were off. Since 1992-1994 DSMs did not have pop-up headlights, this switch is not installed. There is a "blank" where the switch would have gone. The installation of such "blanks" is commonplace in automotive design. If desired, a pop-up switch, fog light switch or other stock DSM switch can easily be installed into the "blank" spot to control auxiliary lighting or other special equipment.

It is true that the pop-up switch is slightly redundant on 1990-1991 cars since the headlights pop-up automatically when switched on. It is possible to prevent them from doing so. Owners sometimes want to do this to allow them to look "cooler" when using the headlights as daylight running lights. Others prefer to run the headlights down and use the high beams to make up for the lost light. [Note: The writer of this FAQ does not recommend operating the headlights down at night.]

"When the yellow light is on, the air conditioner delivers cold air when the interior of the car is hot and then gradually tempers the air as the interior of the car cools down. This is done by gradually changing the temperature set points at which the compressor cycles to higher temperatures."

"To see exactly how this all works check out the graph at the bottom of page 24-4 of the "Technical Information Manual"."

Most people believe that the green light means the air conditioner compressor stays on all the time. This is not true.

From a post by Lorrin Barth:

"When the green light is on the air conditioner cycles off when the oulet temperature of the evaporator drops to 37 degrees and cycles on when it rises to 39 degrees. In other words, cold air all of the time. Of course, as in really hot weather, the evaporator temperature may take a long time to drop to 37 degress, and this is going to depend on the condition of the system too, making you think it never cycles.

So, as you can now see, the compressor cycles in either mode. To see exactly how this all works check out the graph at the bottom of page 24-4 of the "Technical Information Manual". "

This is peculiar to 2G DSMs. Likely the factory installed this feature to ensure that the defrost air is dry. Trying to defrost a freezing windshield with humid air does more harm than good, and blowing snow can easily get into the fresh air intakes.

It was previously posted that the rationale for this 'feature' is that disuse of the A/C feature during winter can lead to premature seal cracking. Having the A/C on with the defrost ensures that the A/C system stays "active" and keeps the seals properly wetted. This might be considered suspect since chronic A/C seal failure is not known to be a problem on 1G DSMs - even Canadian ones.

If you hate it, you can remove the little tab on the vent dial that is responsible. Essentially, there is a small tab on the A/C selector knob that automatically trips the A/C if the defroster is selected. Breaking off the tab "fixes" it.

The Last Word: Your experience may vary, but the only reason I keep A/C in my car is to dry the air and keep the windows fogging up in rainstorms.

Your brake fluid is probably low. Check it. Another possibility is that your brake pads are wearing out.

Some owners have found that the brake light comes on when it is cold out. However, this is often a symptom of another problem, and not the problem itself. Check your brake system to make certain.

Another possibility is some malfunction in the antilock braking system of your car. If you find your fluid is ok, have the ABS system checked out. It has been reported that 1991 cars may occasionally experience a glitch in a wheel sensor, causing the ABS system to reset.

Still another possibility is that you are accidentally bumping the parking brake handle with your right knee. This can happen to taller people.

This may be a symptom of a failing battery - the ABS system can misbehave under low-voltage conditions.

Changes the shift points the transmission uses - that's all.  Mitsu recommends that the economy setting not be used except over 50 MPH, to avoid unnecessary wear and tear on the transmission.

That is the ECU turning off. It is perfectly normal.