Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

idle problem video

Discussion in 'E30 (1984-1993)' started by joe2skate, Jan 22, 2010.

    joe2skate guest

    Post Count: 13
    Likes Received:0
    • Member

    Elkoholic

    Post Count: 183
    Likes Received:0
    Wow, that's quite a surge! Have you replaced the idle control valve? Mine was doing this when I first bought it (although would only surge to about 1200-1500, and do it every second or so). I replaced the ICV, and all was well...
    • Member

    az3579

    Post Count: 3,270
    Likes Received:3
    Stuff I've done in the past to *try* to remedy my idle problem I had:
    Replaced ICV (2 times), replaced ICM (Idle Control Module in the glovebox), replaced all vacuum hoses. I have not tried replacing the ECU and changing the intake boot.

    Verify you have no vacuum leaks. Clean your ICV. I'm willing to bet my problems were caused by a cracked intake boot, so check that for any cracks.
    • Member

    Elkoholic

    Post Count: 183
    Likes Received:0
    Oh yeah, changed my intake boot, too, and that made a difference...

    joe2skate guest

    Post Count: 13
    Likes Received:0
    thanks for all the suggestions...

    today i did a deep down inspection and two cracks in my intake boot on the bottom side and also found an orange connector on the upper thermostat housing that, when the car was running, when i thouched it and wiggled it around it made the car react by changing idles. my repair manual doesnt throughly say what it is but if anyone has anyt suggestions that would help. definently vhanging the intake boot. thanks again
    • Member

    MGarrison

    Post Count: 2,795
    Likes Received:143
    Bentley manual mentions multiple causes of warm engine idle problems -

    Coolant temperature switch faulty
    Throttle switch incorrecto adjusted or faulty
    throttle plate incorrectly adjusted
    coolant temperature sensor faulty
    coolant level incorrect
    fuel injectors clogged leaking or faulty
    Idle air stabilizer valve (ie, idle control valve) out of adjustment or faulty
    O2 sensor faulty
    Cold start system operating continuously
    Charcoal canister purge valve faulty
    intake air leaks
    incorrect ignition timing (I'm not sure this applies to motronic-controlled vehicles, might be '84 318i only)
    fuel pressure regulator faulty or hose to regulator leaking or faulty
    Motronic 1.1 ECU faulty, or L-Jetronic control-unit faulty.

    Since the problem is apparently temperature related, if your car has a cold start valve and thermo-time switch, test those as per the Bentley manual, plus the coolant temperature sensor, and coolant temperature switch, again as per the Bentley manual (Section 6, pgs. 40-47).

    Also see the motronic schematic on pg. 35 in the same section. The Bentley manual is a little vague in a later reference, (Cooling system, section 7, pg. 7, fig. 3.5), explaining a sending-unit quick test, but the motronic diagram seems to refer to the same sending unit as a thermo-time switch. Bentley indicates that the coolant-temperature sensor connector for your car should be white. I believe they're referring to the connector in the thermostat housing. Anyway, test those for function, might be worthwhile to check their ground continuity as well.

    Let us know what you find. I'll venture a guess that one possibility is the control unit isn't getting a signal that the engine is warmed up, and your surge is the control unit is telling the fuel injectors to open longer, delivering more fuel than is needed and making the surge. That guess could be all wet though. Idle tests assume you have no vacuum leaks, and there's plenty of places you can get those.

    Good luck :)

    joe2skate guest

    Post Count: 13
    Likes Received:0
    wow thanks MGARRISON...my haynes manual doesnt have any of that info. so far ive gone through about half of that list but i think it does have something to do with engine temp because everything else is FINE lol.

    aurelius guest

    Post Count: 3
    Likes Received:0
    Have you found a fix yet? If not and based on what you described above, sounds like you need a coolant temp sensor. There are 2 of them in the thermostat housing, one sends a signal to the engine control unit (aka Bosch DME) and the other feeds the temp gauge in the instrument cluster. The connector for the one that feeds the ECU/DME is usually blue but at $8.50, try it. Installed one in my '87 yesterday. Part # 13621357414. Pelican Parts. They also have the Bosch version for $20 and the BMW-branded one at $60+.
    • Member

    Zdaneman

    Post Count: 105
    Likes Received:0
    Try this...

    Mine was 02 sensor, it helped but the final fix was the idle control value. Bavarian Auto parts has them both.

    Good luck!

    Zdaneman sends
    • Member

    MGarrison

    Post Count: 2,795
    Likes Received:143
    I hope he got a Bentley manual by now; the Haynes manual is useful, but pales in comparison to the detail offered by the Bentley manual. Hope the issue is resolved by now, regardless.

    joe2skate guest

    Post Count: 13
    Likes Received:0
    problem soon to be resolved...i hope.

    got a new icv, o2, intake boot, couple hoses, head gasket with studs and a valve adjustment coming my way in the next couple weeks when i get paid.

    i started working at a local independent bmw shop so itll be nice to be able to work on it there when i get the parts instead of my dirveway with the car on bricks.

    oh and i got a chilton.
    • Member

    bcweir

    Post Count: 1,263
    Likes Received:5
    When you're ready to stop guessing and shooting blind at a problem..

    The Haynes manuals and Chilton's manuals are cheaper for a reason = less information means less cost to the publisher to put the book out. The Bentley isn't 100 percent perfect either, but short of putting a BMW engineer on your payroll or paying hundreds for the BMW factory service documentation, the Bentley is the best out there.

    I completely concur. Both the Hayne's manuals and the Chilton's manuals leave out a LOT of important information. The Bentley manual is pricey, but you really do get what you pay for.

    Did (or does) the Chilton manual correctly identify the problem? Does it accurately illustrate and describe how to fix an issue?

Share This Page