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 Frequently Asked Question's
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. Courtesy of the DSM VFAQ site.

1.) What exactly is a DSM?
 Technically, a DSM is a car built by Diamond Star Motors, a joint venture between Mitsubishi and Chrysler. Diamond-Star Motors was officially dissolved in 1993 after the design and production tooling for the 1994 and 1995 cars was complete. Mitsubishi Motors continues to operate the plant formerly responsible for DSM cars under sole ownership. The "Eagle" brand name was originally created as a method of integrating AMC dealerships and products into Chrysler. It continued for some time as a marque, much as General Motors now continues to market under several brand names. It was eventually discontinued as Chrysler sought to improve their business operations.

2.) What are the differences between a [model year] and a [model year]?
 There are many differences, both major and minor, between various model years. To date, no comprehensive list exists which details all of the changes; to list them all is beyond the scope of this FAQ. A few of the high points are:

1990
  • Inagural model year of the DSM.
  • Pop-up headlights.
  • Some high-end models had wheel covers.
  • All ECUs had EPROMs.
  • Front brakes change during the model year.
  • 1.8L models have the 4G37 engine, all others have the 4G63 engine.
1991
  • ECU changes mean that 1991+ ECUs don't operate the 1990 tachometer correctly.
  • Most ECUs had EPROMs.
  • First model year with ABS available. ABS not available with limited-slip differential (LSD).
  • All high-end models had alloy or mesh wheels.
  • First year of the Galant VR-4 - 2000 sold in the American market.
1992
  • Non-popup headlights introduced on all models.
  • The first AWD Lasers were introduced.
  • Few (or no) ECUs have EPROMs.
  • ABS now available with LSD.
  • The engine changes from the 6-bolt version to the 7-bolt version in April.
  • Second and final year of the Galant VR-4 - 1000 sold in the American market.
  • The last year of the Dodge 2000GTX.
1993
  • "Big brake" 2-piston front calipers become standard on turbo models.
  • 7-bolt engines are now standard.
  • No ECUs have EPROMs.
  • Diamond-Star Motors ceases to exist.
1994
  • All cars built to California emissions standards - there are no "Federal" cars.
  • The last year of the 1G car and the 1.8L NT models.
  • The last year of the Plymouth Laser.
1995
  • The inagural year of the 2G DSM.
  • Significant changes to the engine, body, and electronics.
  • New transmissions.
  • All ECUs have EPROMs.
  • Non-turbo models are based on the Chrysler 420A engine instead of the Mitsubishi 4G63 engine.
  • OBD-II becomes standard on DSMs, along with two oxygen sensors.
  • Mitsubishi begins using some substandard crankshafts, leading to crank walk on some 2G cars.
1996
  • The first year of the convertible Spyder.
  • The Mitsubishi 4G64 engine is offered, in the Spyder models only.
  • ECUs stop having EPROMs.
1997
  • Additional body changes from the 1995/1996 models.
  • Minor changes to the ECU code.
1998
  • Minor changes to the ECU code.
  • After many years, Mitsubishi finally issues a recall on the AWD DSM transfer case.
1999
  • The last year of the 2G car, and of the 4G63/AWD DSM platform.
  • The last year of the Eagle Talon. Chrysler drops the Eagle marque.
2000+
  • 2000 - The first year of the 3G Eclipse.
  • 2002 - The first year of the Lancer (non-Evolution) in the United States and Canada.
  • 2003 - The first year of the Lancer Evolution in the U.S.A.
  • 2004? - The first year of the Lancer Evolution in Canada?

3.) What kind of recalls have there been on DSMs?
 The major recalls on DSMs have been for:
  • 1990-91 timing belts;
  • 1992 timing belts, under a separate recall;
  • 1990-91 seat belt latches;
  • 1990-91 oxygen sensors; and
  • 1990-1998 transfer cases.

4.) My engine makes a 'tick tick tick' sound. What is it? Is there a fix?
 This is commonly attributed to the hydraulic lash adjusters (lifters) used in the DSM cars. Other cars have similar problems - Mazda owners, for example, refer to them as HLA problems. Other possible causes include excessive carbon buildup on the valves and piston heads. The general consensus is that this problem is not damaging to the engine. Indeed, many owners have lived with the problem for years with no side effects. In extreme cases, it is possible that the ticking may be picked up by the ECU as knock, causing a retardation in timing that will cost some engine power. This case seems to be the exception, not the rule, since the DSM ECU only 'listens' for knock during specific time intervals. In the past, owners have reported that their tick appeared or went away with certain oil brands, oil weights, oil filters, oil pressures or the like. These 'solutions' appear to be car-specific and do not represent a real fix, but some experimentation may help alleviate the problem. Some owners find that adding a small amount of extra oil helps to raise oil pressures and minimize the ticking, but again, it doesn't work for everyone. Simply replacing the problem lifters is unquestionably the best option. The lifters have been redesigned to eliminate the tick. There have actually been a few versions of the lifters. The original were Mitsubishi part number MD149309 used in 1990 to 1997 cars. A redesigned version (part MD337687) was then introduced, and was replaced yet again by part MD377054. This latest part number is reportedly the best version but the availability may be limited if dealerships still have some of the older part still in inventory.

5.) How do I prevent fuel cut?
 This question comes up a lot, mostly because people misunderstand what fuel cut is for, and why it occurs at all. The simple answer is that because fuel cut is pre-programmed into the ECU, there is no method of disabling it. There are no modifications that can do so, aside from an ECU upgrade that eliminates fuel cut. Upgraded fuel pumps, injectors, and fuel pressure regulators do nothing to avoid or eliminate fuel cut. NOTHING. That being said, there are some methods (some cheap, some not) of postponing fuel cut. All the methods work on one principle: fooling the ECU into thinking there is less air entering the engine than, in fact, there is. This can be done by adding unmetered air, or by changing the sensor inputs used by the ECU to determine air mass. Of course, these methods usually mean the engines run leaner than stock.

6.) My transmission shifts poorly. Is there a fix?
 Poor shifting is a hallmark of 1G cars. 2G owners have vastly improved transmissions, and do not generally suffer from bad shifting. For 1G cars, there are several fixes, Solution #1 came up in 1992 when the first TSB called for adding a 'friction modifier' to the transmission fluid. The modifier increases the frictional coefficient of the fluid, so the synchronizer rings (synchros) match speeds faster. There have also been several synchro design updates throughout the various years, intended to improve the crunchy shifting. Of course, to take advantage of these requires a transmission rebuild. Many DSMers end up using Redline MTL, BG Synchroshift or GM Synchromesh in their transmissions. All of these fluids have the same purpose - to increase friction, just as the Mitsu fluid modifier is intended to do. Most owners report at least some improvement with the new fluids, but most experience significantly better shifting. Opinions and experiences vary. Recent experience suggests that Redline MTL gains in shifting performance by sacrificing synchro longevity. This is not exactly news, but more and more owners are reporting this problem with MTL now that there are alternative fluids available. Many owners considered the tradeoff to be well worth it. However, more people are now recommending a mix of Redline MTL with MT-90 gear oil, to combat both problems at once.

7.) I installed an [exhaust/test pipe/cat] and now my "Check Engine" light is on? Is there a fix?
 This is usually a 2G problem. So far the only "fixes" are to replace the missing oxygen sensor, or to try and create and electronic replica "sensor" that makes the ECU believe the original sensor is still in place. Since the OBDII software in the second generation ECU also does sensor diagnositics, creating a fake sensor can be a touch tricky.

8.) My car still shudders/vibrates when cruising, even after wheel balancing! Is there a fix?
 Vibration problems can be caused by a number of things, including:
  • warped brake rotors
  • badly balanced tires
  • flat-spotted tires
  • bent or out-of-true wheels
  • mud or debris inside the wheel

9.) Does installing a [component] void my warranty?
 In the United States, it does not do so automatically. According to the Magnuson-Moss Warranty Act, the Federal Trade Commission (FTC) has made it illegal for modifications to automatically void your warranty. The important point is that the dealer has to be able to demonstrate that the modification was the cause of the failure. However, some dealers are not keen on modified vehicles and may claim that the problem is somehow related to the vehicle modifications. Plus, it is usually better to avoid the entire mess rather than enter an antagonistic relationship with your dealer. Most people recommend talking to the service managers and finding out which ones dislike modifications, and which ones don't mind. Other people install modifications that can be easily reversed, so the car can revert back to stock for each trip to the dealer.

10.) Why do these cars require premium fuel? Is it worth it?
 Strictly speaking, DSMs do not require premium fuel. However, the car was designed to accept higher-octane gasoline for a reason. Octane is not a measure of the amount of energy in gasoline - rather, it is a measure of how well the fuel resists preignition, also known as detonation or 'knock'. Detonation is very hard on the engine, and must be avoided. The DSM cars incorporate a knock sensor specifically for the purpose of detecting knock. Higher-octane gasoline resists knock better than lower octane gasoline. During normal operation, the engine control unit (ECU) adjusts the engine timing as far forward as it will go. This provides maximum power, but also increases the possibility of knock. This is especially true for turbocharged or supercharged engines, such as the 2.0L turbo 4-cylinder found in the upper model DSMs. Note that the ECU hears knock all the time - the problem has to be persistent to generate a reaction from the computer. If the ECU detects excessive, continuous knock via the knock sensor, the engine timing is retarded until the knock goes away. This results in a power loss, but saves the engine from damage. So, if you fill up with 87 octane gas, your ECU will be forced to retard the timing quite a bit, and you will not get the rated power from the engine. Not only that, but the ECU may also be forced to limit turbo boost levels to accommodate the lesser quality gasoline, which again means a significant power loss. And yes, the ECU does have the power to do that. 		.
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