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| Thread ID: 85795 | 2007-12-22 04:21:00 | My Car won't idle.. Any mechanics in the house? | radium (8645) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 623632 | 2007-12-24 04:02:00 | I'm not sure if mitsi are the same, but our corolla had a rough idle and when stopped at the lights and being an auto it wanted to stall, it turned out to be a sticky solenoid that I think controls throttle . Not 100% sure because a mate fixed it . Original fault felt like a low idle, Since about 1968 or so, almost all engines required some sort of idle compensator device to keep them running during changes in loads to the engine at idle . That includes using the AC when the compressor cycled or you turned the power steering and dragged the engine down a little with the power used by it . . . etc . Carb'd engines had a sort of plunger-solenoid . . . the early ones had just one step and they were set at the time of tune-ups to keep the engine running . Later on with the advent of feed-back carbs, they could have a little more . . but only slightly more control of the idle with changing loads . Fuel injected engines have it all over the carbs as they can even individually adjust the air/fuel mixture in single cylinders now . Mostly we see an ISC (idle-speed-control) motor in the throttle body to bypass air into the plenum and allow the engine to get enough air . . . the ECM adding fuel as necessary to keep the idle constant and consistent . This technology has caused grief to owners, but a godsend to shops with the necessary diagnostic equipment . It costs big-time to operate a shop any more . School, high paid techs and very costly and sometimes one-model-only test equipment . . . . sets the shop owner on his butt for expenses and overhead . I have a lot of disrespect for most of the Euro models as they have had the gaul to keep their test criteria secret and not let it out to the individual shops . Mitsubishi and sadly Mazda too have kept a lid on what they call "proprietary" values and codes . Kia was another one until we invoked the US/Federal Right To Know statute on them in a class action lawsuit . |
SurferJoe46 (51) | ||
| 623633 | 2007-12-27 09:44:00 | Update for ya, I took my car in to a mechanic today, not my usual one and not a mitzi specialist either he is closed until the new year - which is no good for me. My boss rang his mate who is also a mechanic in town and he looked at it for me. I forgot all about just asking for a diagnostic test, don't know why I forgot, I just handed him the keys and told him the problem, Then I got a shock later on when I had realised what I done , I was thinking, what a big mistake I made, was probably going to cost me a fortune. $$$$. Any who, they replaced some part - throttle part I think he said and it's all go, cost me $90 for the part plus an hour labour, so about $150 all up he said, going to pay tomorrow so will know exact price then. Thanks for your help guys. |
radium (8645) | ||
| 623634 | 2007-12-27 10:29:00 | Betcha 'twas the ISC motor! :D | feersumendjinn (64) | ||
| 623635 | 2007-12-27 16:13:00 | In any case . . . it pays to not use much alcohol-based fuel in the future . It has a tendency to gum the works up in the ISC motors and make the throttle body sticky . The ISC then tries it's hardest to return the idle speed to a preset or adaptive value and since it can't, it dies trying, stalled at a higher position that it wants . If you open the air intake on the engine . . . as close to the place where the throttle linkage is, you'll see a dark black or brownish-black residue that is the congealed vapors of your poor fuel and/or the crank case vapors from a non-vegetable-based oil . And if you regularly clean the throttle body in the future, you'll likely not have this same problem again . Use good fuel Don't bother with snakeoil fuel injection cleaners in the tank Use good oil (Castrol and Valvoline come to mind) Use Berryman's B12 Chemtool in the throttle body at least every six months . . . with a soft (old) toothbrush and your index finger as a brush . |
SurferJoe46 (51) | ||
| 623636 | 2007-12-27 16:49:00 | I think this is typically the same as your Galant DSM 2 . 0 - 4 cylinder engine w/dual overhead cam engine's ISC ( . imagef1 . net . nz/files/Gallant_ISC . JPG" target="_blank">www . imagef1 . net . nz) . . . . and here's a close-up of it ( . imagef1 . net . nz/files/Gallant_ISC_Closeup . JPG" target="_blank">www . imagef1 . net . nz) as it is beneath the throttle body . The I . S . C . is on the rear side of the throttle body, on top of the engine toward the back . It has a tan plastic plug connecting to the harness (some late models are black plastic . ) The other half of it (the moving part) is sticking inside the throttle body . This location causes all sorts of contamination possibilities . . . a short sighted plan by Mitsubishi . . . but typical of their engineering . One other consideration . . . . . Mitsubishi ECMs are quite easily damaged by the current draw of the ISC while it is trying to comply with the command to close the valve, resulting in overload and usually, not ALWAYS . . . fatal damage to the ECM . If your symptoms change for the worse or don't go away at all, then you have another yard or two of money to spend . Mitsubishis are kinda weak kittens in the electronics department with little or no provision for overloads to the ECM . They should use a relay/quad driver or so, but they are cheapskates ( :2cents: ) in the bean-counter department and you get short shrift as a buyer/user . C/P from another site about Mitsubishis . . exclusively . . . . "Mitsubishi ISC motors can fail and cause unrepairable failure to the ECM . Most dealerships as well as our technicians recommend replacing your ISC when the ECM engine control computer is repaired or replaced . Symptoms of failing ISC control motor include: idle surge, failure to idle up on cold start, idle oscillation with engine idle reving up & back between approximately 900 to 1500 rpm's at idle (which should be around 850 with engine at operating temperature) or an unresponsive high or low idle . The car should compensate and idle up when the a/c compressor, power steering or when fan is running . It's likely you'll need to replace this at some point in your Mitsubishi . " |
SurferJoe46 (51) | ||
| 623637 | 2007-12-27 17:48:00 | I think this is typically the same as your Galant DSM 2 . 0 - 4 cylinder engine w/dual overhead cam engine's ISC ( . imagef1 . net . nz/files/Gallant_ISC . JPG" target="_blank">www . imagef1 . net . nz) . . . . and here's a close-up of it ( . imagef1 . net . nz/files/Gallant_ISC_Closeup . JPG" target="_blank">www . imagef1 . net . nz) as it is beneath the throttle body . The I . S . C . is on the rear side of the throttle body, on top of the engine toward the back . It has a tan plastic plug connecting to the harness (some late models are black plastic . ) The other half of it (the moving part) is sticking inside the throttle body . This location causes all sorts of contamination possibilities . . . a short sighted plan by Mitsubishi . . . but typical of their engineering . One other consideration . . . . . Mitsubishi ECMs are quite easily damaged by the current draw of the ISC while it is trying to comply with the command to close the valve, resulting in overload and usually, not ALWAYS . . . fatal damage to the ECM . If your symptoms change for the worse or don't go away at all, then you have another yard or two of money to spend . Mitsubishis are kinda weak kittens in the electronics department with little or no provision for overloads to the ECM . They should use a relay/quad driver or so, but they are cheapskates ( :2cents: ) in the bean-counter department and you get short shrift as a buyer/user . C/P from another site about Mitsubishis . . exclusively . . . . "Mitsubishi ISC motors can fail and cause unrepairable failure to the ECM . Most dealerships as well as our technicians recommend replacing your ISC when the ECM engine control computer is repaired or replaced . Symptoms of failing ISC control motor include: idle surge, failure to idle up on cold start, idle oscillation with engine idle reving up & back between approximately 900 to 1500 rpm's at idle (which should be around 850 with engine at operating temperature) or an unresponsive high or low idle . The car should compensate and idle up when the a/c compressor, power steering or when fan is running . It's likely you'll need to replace this at some point in your Mitsubishi . " Is all of the above french for solenoid? |
plod (107) | ||
| 623638 | 2007-12-27 22:12:00 | Is all of the above french for solenoid? Most emphatically . . . NO! It's a controlled stepper motor with 256 positions . ( #'s zero to 255 ) A solenoid has one or possibly two energized positions not counting unactivated . |
SurferJoe46 (51) | ||
| 623639 | 2007-12-28 08:55:00 | I got the invoice for my car. The part they replaced is called a Stepper Motor, is that the same thing? Cost me $187.50 all up, which was more than what he said but he was only guessing, I was hoping for it to be under $200, so I'm quite happy. |
radium (8645) | ||
| 623640 | 2007-12-28 11:49:00 | The part they replaced is called a Stepper Motor, is that the same thing? Yes it is, I was right, woohoo! :) |
feersumendjinn (64) | ||
| 623641 | 2007-12-28 18:43:00 | Who needs fancy equipment, we've got expert, remote diagnosticians right here!! :thumbs: :thumbs: | johcar (6283) | ||
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