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Rogue voltage or idle control system malfunction? 200

Well, we have made progress. Our initial problem was that the car was not driveable. Swapping the AMM for one off a diesel, (same part number) got us out of the driveway, but now we are plagued by a multitude of gremlins. Firstly, I shall describe the problem; Driving at any speed, the idle will fluctuate from 1100 to 1500, then to 2000, in that order, every two to three seconds. In conjunction with this erratic idle, black smoke pours out the exhaust. Once every time we drive, the car will cut out completely with no warning, and from time to time the wipers will run for one cycle, on their own accord! As well, we have a minor exhaust leak at the manifold-pipe coupling. ECU tests have confirmed the proper operation of the TPS, ECT sensor, and we show relatively consistent spark. The faulty AMM had produced such rich conditions that we were certain the engine was rife with carbon, so the fuel system was flushed at a garage. As far as our diagnosis goes, we are about to pour brake cleaner into the IACV to free it from grit that may inhibit smooth operation. Our other nagging suspicion is that there is a short in our coil or in the ECU. The nature of the idle hunt suggests a problem with a control component of the idle system, ie. electronic sensor. The last thing we have though of is the Idle Adjustment Screw. Manipulation makes absolutely no difference in idle speed. Does anyone recommend removing this piece and cleaning it? It is possible that the air channel is clogged with oil, I think. Any help would be greatly appreciated. Thanks.








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    Rogue voltage or idle control system malfunction? 200

    What part exectly did you swap with one from a Diesel? Was it a
    *Volvo* diesel? AFAIK, older Volvo diesels used a mechanical
    injection pump with basically no electronics to meter fuel, and
    thus didn't have an AMM.
    .
    -b.








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    Rogue voltage or idle control system malfunction? 200

    Stall tactic: what year Volvo do you own? Guess I could figure it out if I knew what model AMM is used in a diesel.








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    Rogue voltage or idle control system malfunction? 200

    You could do the following:
    1. Remove and clean the IACV with carburetor cleaner. Clean the electrical contacts also.

    2. Remove and clean the throttle body. Clean out that idle adjust airway while you have it out. Don't get carb cleaner in the Throttle Position Switch though.

    3.Check to see the switch works and, when you reinstall the throttle body, be sure to adjust the TPS for proper operation.

    4. Read up on how to check the operation of the IACV and TPS and to set base idle. If you don't have a Bentley manual, you can get help in the 700/900 FAQ.







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