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Mitsubishi Diamante



  • ucscucsc Posts: 48
    Hi Mr. Vivona,

    First of all, I would like to thank you for your dimand and pearl paper about throttle body cleaning. It is well-written, and easy to follow the instructions.

    I have a 92 D LS with 138,000 miles and live in Philadelphia. I had rough idle: 750rpm in P, and 550-650 in D/R since early Feb. Sometimes in D, rpm decreased to 400rpm, then immediately increased to 1,200rpm. (Last Sept. I had idle problem. So I did 120,000 miles maintanance & repair by Mits dealer, who changed idle air control motor, spark plugs and wires, cooling system thermostat, timing belt, etc.)

    I figured out the throttle body could be dirty, so last Sunday (Feb.22) I disconnected the battery, followed your TB cleaning instruction and cleaned the TB. (TB was really dirty!) After I cleaned TB, I started my car. It idled at 2,000 rpm for a while (in cold weather, 28F), but when the temp rised to normal driving temp. It idled at 1,000rpm in P, and 800rpm in D/R. I took a test drive, and the idle was fine.

    However, today even after the car has been driven for 10 minutes, the idle is 1,500 rpm in P, and 1,000 rpm in D/R.
    1) Is it possible that I have messed up the TB? The followed the exact steps in your article.
    2) Is it possibe that because the TB is clean, so the throttle body opening is 'bigger and wider' than it was before when the ECU sends out the same signal to open the TB during idle?
    3) Can I manually adjust the TB? If I can, how can I do it?

    Thanks a lot!

  • ucscucsc Posts: 48

    Today the idle in my 92 D LS is still high, but much better than yesterday. When the car is completely stopped, the idle is around 1100rpm in P, and 800rpm in D/R after it has been driven for 10 minutes. I guess my D need time to re-learn the setting. So I will give it more time to adjust itself before I have to manually adjust the throttle body.

    Mr. Vivona, I am still interested in learning how to adjust the TB. Could you give me some advice?


  • I just purchased '03 Diamante w/ 17K and just love it.

    I discovered a noise coming from the engine/transmission or underside of the car when I go from Neutral to Drive.

    I brought it to a Mitsu dealer to have them look at it. They told me everything looked fine and that it was a normal sound. They told me that the noise is generated from a heat shield from underneath the car. They said the heat shield is properly mounted and secured. They said it is the design of the car.

    Does this sound correct? I can't believe that car of this level would have such a disturbing noise as part of a design.

    Does anyone have an opinion? - Thanks
  • patpat Posts: 10,421
  • lngtonge18lngtonge18 Posts: 2,228
    Well, the infamous warped rotors has reared its ugly head on my 03 D at only 5,500 miles. It started at about 3k as a funny jerky feeling "flat spot" when slowing down at city speeds. I noticed some slight wheel shimmy at higher speeds but just hoped it wasn't going to get worse. Much to my dismay, it has gotten worse quickly. Now the steering wheel shakes badly when applying light to moderate pressure on the brake pedal at highway speeds. Frankly, I'm shocked the issue has shown up so early, especially since I retorqued all the wheels by hand at about 1000 miles and no air wrench has touched this car since the factory. It really is a shame Mitsu hasn't learned to install better quality rotors.

    I will say this car is turning into a bit of a disappointment as far as build quality goes. It's a reliable, nice looking, comfortable car, but the build quality is just not up to the high standards of the considerably cheaper Lancer. Here is another example of a minor annoying issue: the driver's side sunvisor is overly stiff and creaks loudly ever time it is moved. I assume they will have to replace it. I've never had a new car with so many little problems. 5 unscheduled dealer visits in only 5.5k and 3 months is a bit much! To put my position into a little more prospective, my 03 Tiburon is a year old and has 10,600 miles and has yet to see the dealer for anything. It's build quality has been far superior. And that is from a company that only a few years ago was known for junky cars. I just hope this car redeems itself with its reliability.
  • 2dtom2dtom Posts: 1
    Dear Mr. Vivona,

    Just bought a 1992 D SOHC with 152,000. Previous owner said transmission was rebuilt two years ago. Idle was high (2500) and I believe it needs a water pump but the car ran and shifted basically okay. (We also own a 1994 with 160,000 that runs like a top).

    Since the car also had a valve cover(?) oil leak and the engine compartment was COVERED in oil and grime, I took it to a nearby car wash and used engine cleaner and the sprayer to power wash the engine compartment---(I should have known better!)

    The car didn't start right away but finally did. I drove it to a gas station to get gas (less than 1/2 mile) filled up and when I started it back up it would not move when shifted in to drive or any of the lower gears or power/od modes. It would go into reverse.

    I pulled the car(in reverse) into a side lot and let it sit. After a couple of hours of starting and trying the gears--it finally went into drive after hesitating. I drove it a few miles running very rough. At a friends suggestion we sprayed wire dry into the various electrical connections in the engine compartment. I was able to drive the car home and it seemed to run better but was still "rough".

    After parking the car it will not move in drive or lower gears --it will still go into reverse. Fluid level and color looks okay.

    I cleaned the throttle body which was really dirty--it ran better--idle was still high and it would not go into drive.I adjusted the throttle cable bracket and idle is closer to 1500.

    I tried reading codes from the OBD sensor and the proper procedure(I am assuming it is a style one) with a digital multi tester but have a hard time interpreting the quick flashes to translate into code. I also tried an analog meter but could not distinguish needle movement between codes (they all seemed that same output).

    Do you have any ideas as far as which sensor would effect or cause this condition or what remedies I might try? Will the OBD show trans faults or do I have to access the TCM module? HELP!

  • lngtonge18lngtonge18 Posts: 2,228
    I took my car in for warranty repairs last weekend. They replaced both washer nozzles and turned the front rotors. The car stops much smoother and more securely now. But I'm really worried that they will warp even faster now. The washers spray stronger and quicker so that was fixed. They responded to my complaint on the creaky driver's sunvisor by saying, "it just needs to be used more", after putting grease marks on the visor (ggrrrrrr). Funny, the passenger side doesn't make the noise and thats almost never been used. I let it drop for now since I had already wasted 3 hours of my Saturday waiting for them to finish this minor work. They still haven't been able to fix my broken cargo net since they don't have a welding machine. So it lays useless in my trunk. I must say the mounting system for the net is a piece of junk!

    Overall, my first 6000 miles with this car hasn't been too enjoyable. But I do love the strong V6, smooth tranny and ride, and attractive comfortable interior. Mitsu needs to tighten the quality controls on the Australian plant though.
  • and retorque the wheel lugs. The most common cause of warped rotors is overly tight lugs that are put on with an air impact wrench. Somewhere around 85 pounds should be correct. If they are using the air wrench they are probably tightened to more like 120. Keep a close watch on that torque and you should have less problems.
  • glabglab Posts: 11
    Went to the dealer for steering wheel shimmy at or above 65 MPH when I apply the brakes. The car has 22500 miles.

    I had the same issue at 16K miles and they turned the rotors and everything appeared to be fine........

    Now the dealer is replacing them under warranty ( Of course they do not have them in stock..... wonder why) and will take a week to get.

    The Mitsu rep. kept trying to blame very heavy braking ( Brakes got excessively HOT) caused the problem, but I see no signs of excessive heat at the surface of the rotor. I would expect to see some signs of overheating ??? The rep stated they checked the Caliper release mechanism and the brake operation looked fine.

    The dealer has been the only service to torque the lug nuts so I don't expect over torqueing was the problem. I can only conclude the metal alloy in the rotors is poor.....

    I hope I get better results with the replacements......????
  • and check for proper torque even after going to the dealer. I can tell you from watching the techs in more than one dealership that only the minority of them do it right. Most of them just grab the air gun and "snug them up". It may not help but is guaranteed not to hurt if you loosen them and then tighten to the correct torque setting.
  • glabglab Posts: 11
    I own one and will check the lugs tonight. Just curious, How long can the Rotors be exposed to improper Lug torque before any damage is done. If it's immediate not much you can do after the fact...?
  • glabglab Posts: 11
    Well, just finnished checking the lug nut torque and found that most lug nuts exceeded 150 ft-lbs. to break free. The wheels had just been mounted by the "dealer" two days ago......

    "subarusaleshou" was correct !! DO NOT TRUST THE DEALER !

    I validated that my brand new Eclipse GTS (That the dealer has not touched yet) had 70 ft-lbs lug nut torque.

    It appears an investment in a torque wrench is well founded !!
  • is important however I don't think a couple of days is going to hurt it. I am not a mechanic at all but I believe it would take at least several hundred miles before it would become problematical. I'm glad you got it corrected right away. I believe you won't have that problem in the future as long as the torque is kept around 75 pounds or so.
  • vivonavivona Posts: 410
    Regular visitors to this site know that I have written an extensive article on the subject of brake pulsation and wheel lug nut torque. Read about it at

    You can bet that 90% or more of the time a mechanic will incorrectly torque the lug nuts. I have easily gotten over 100,000 miles on rotors by double-checking and retorqueing the lug nuts immediately after any mechanic has touched my, er..., wheels. On my current Diamantes, I have 37,000 miles on one and 15,000 miles on the other and neither car has measurable runout.

    In all my years of dealing with this issue, I have found them properly tightened maybe one or two times. In most cases, they are in excess of 150 ft. lbs. even if they use a torque wrench or torque stick, due to not knowing how to properly use these tools. For instance, they will fully tighten the first nut, then fully tighten the one across from it. That creates a lever action that will overtighten the first nut. The proper procedure is to tighten all to half torque, then go back and final tighten them to 75 ft lbs. Or they will tighten all the nuts with an air impact wrench to over 200 ft lbs, then use a torque stick or hand torque wrench to finish the tightening, obviously oblivious to the fact that the nuts are already too tight and the torque wrench doesn't loosen them to the correct torque. In many cases, they forget to tighten the one nut that has the lock on it, so I have four grossly overtightened and one finger tight.

    It is not the actual rotor warp you feel in your brakes, it is the variation in the thickness of the rotor that results from the pads wearing against a warped rotor. It takes about 3,000 to 6,000 miles for the warp to create enough disk thickness variation for you to feel it. So a couple of days being overtorqued isn't a problem, though your alloy wheels can be cracked or crushed by the excessive tightness, or the lugs themselves can be stretched and weakened, so it is best to demand they use hand tools or a torque stick from the very beginning or reinstallation and even then you should retorque them to the proper torque.

    Please also note that if they turn the rotors off the car or by using a hub mounted lathe, they can't get to zero runout and brake pulsation will occur in 3,000 to 6,000 miles. The only proper way to turn rotors is with a caliper-mounted lathe.
  • ldbrickerldbricker Posts: 140
    for a more detailed explanation and excellent information as usual. Following the same principle, I've never had brake work on my cars. I usually trade by 60-70k so I haven't fully capitalized on them but certainly have appreciated that a small and simple check on my part saves me from the problems so many have every 25-30k.
  • lngtonge18lngtonge18 Posts: 2,228
    Well, since no one is talking about their Diamante, I guess I will give an update to liven things up a bit. Since the warped rotor issue, things have finally settled down. I've had no more problems with my car so I'm finally beginning to enjoy it again. The car is such a comfortable and serene cruiser. I love how the tranny quickly downshifts and the car just effortlessly overtakes slow drivers on 2 lane roads.

    I have been fairly impressed with the gas mileage my car is getting. My mileage has been averaging 20 mpg pretty consistently in 100% heavy city traffic and suburban driving. This is including some aggressive driving here and there, such as gunning it to feel the powerful low end torque and taking it to the redline a few times. Considering the car is rated at 17 in this type of driving and has a large V6, I'm quite happy with the mileage.
  • ldbrickerldbricker Posts: 140
    I am getting about 24.5 with my RalliArt automatic. I hope it will go up a little when it's got some more miles. Right now I have less than 900 on it. I'm really enjoying it as well. I really like the wheels on the 04 Diamante. We just got a black VR-X in that is REALLY a beautiful car.
  • vivonavivona Posts: 410
    On both our 1999 and 2002 models, we get 19.5 in town and 29-30 on the highway. It is interesting that the highway mileage is as good as any rental car (Grand Am, Sebring, Century, Camry, Galant,etc.) I have rented on vacation, despite many of the rental cars having a smaller 6 or even a 4-cyl engine.

    Mr. Vivona
  • ldbrickerldbricker Posts: 140
    that would look really nice in my driveway next to the black VR-X that would also look very nice in my driveway. I better remember to throw away a dollar on a lotto ticket since it's $37M tonite.
  • diamantdiamant Posts: 7
    I also had the issue of warped rotors because of over torqueing. I just had the front ones replaced and the rear ones were machined.

    You could buy rotors from the dealer $180+ a piece but the Raybestos rotors ($80 a piece) as just as good. My mechanic thinks Raybestos makes the Mitsubishi ones anyway.

    Brake pads are however a different story. You only pay a small premium, $134 for dealer parts compared to $120 for after market but the difference is huge. The dealer parts just fit so nicely and are build way better than the best after market. My mechanic just loves Mitsubishi brake pads. He says he will never recommend after market brake pads for Mitsubishi anymore. He says I did the right thing by insisting on dealer brake pads.
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