1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Engine Idling Speed

Discussion in 'Problems, Fixes, Tips...' started by mac1962, May 13, 2014.

  1. mac1962

    mac1962 Copenworld Newbie

    Joined:
    Feb 22, 2014
    Location:
    Leicestershire, England
    Car(s):
    2004 Copen 0.7 litre Reg WV04 MZZ
    Hi,

    Even when my engine is warm, the idling speed seems to be around 1200 rpm if the tachometer is to be believed. This seems high.

    Can anyone please share their approximate idling speed when warm?

    Is the idling speed adjustable.

    I've got sooty exhaust pipes, so maybe I'm running rich or need a new air filter. ( Only had the car a couple of months.... )
     
  2. DaG

    DaG Copenworld Guru

    Joined:
    Jul 11, 2012
    Location:
    Sunderland
    Car(s):
    Copen 1.3
    Just under 1000 rpm Around 800 - 850 is the normal idle speed.
    Youre running rich which explains the black exhaust. I would service the car then take it for a blast down a fast road as a starting point to fixing it.
     
  3. mac1962

    mac1962 Copenworld Newbie

    Joined:
    Feb 22, 2014
    Location:
    Leicestershire, England
    Car(s):
    2004 Copen 0.7 litre Reg WV04 MZZ
    Thanks for the advice. I'll get my hands dirty at the weekend. Cheers!
     
  4. Rex

    Rex Copenworld Pioneer

    Joined:
    Oct 20, 2009
    Location:
    Cardiff
    Car(s):
    Copen
    At least on the 1.3, the idle speed is fixed by the ECU.

    Is it possible the throttle cable cable is too tight?

    I really am no expert, but I believe the mixture is controlled by the oxygen sensor before the CAT. In normal running the sensor should be switching every few seconds.

    One other possible cause I can think of is the temperature sensor. Does the gauge work ok?

    Anybody else that can comment on this? I only know the 1.3 engine.

    Rex.
     
    Last edited: May 13, 2014
  5. trustafox

    trustafox Copenworld Guru

    Joined:
    Nov 19, 2012
    Location:
    East Mids
    Car(s):
    Yes
    All exhausts get some carbon deposits even if running in spec. Its not a problem unless yours has an excessive build up. So I'm saying that might not be a result of the high idle speed.

    Does it have an idle control valve? if that gets blocked/stuck or plain fails then it will result in a high idle speed other wise the engine would stall. The ECU recognises there is a problem and ups the revs.

    If things are working correctly an old filter shouldn't cause rich mixture/sooty exhaust because the ECU should adjust the fuel to match the amount of air coming in. It would mean you will be down on power, but probably not significant. Unless you have been on the Paris Dakar rally and got an inch of sand on your filter.
     
  6. DaG

    DaG Copenworld Guru

    Joined:
    Jul 11, 2012
    Location:
    Sunderland
    Car(s):
    Copen 1.3
    Leaks in the vacuum pipes can cause a fast idle as well.

    Unfortunately today's cars are not very DIY diagnosis friendly so after checking a few obvious possibilities taking the car to a garage with diagnostic gear is probably the best bet.
     
  7. trustafox

    trustafox Copenworld Guru

    Joined:
    Nov 19, 2012
    Location:
    East Mids
    Car(s):
    Yes
    you'd had your turn!
     
  8. Number6

    Number6 Copenworld Veteran

    Joined:
    Apr 25, 2013
    Location:
    Dublin
    Car(s):
    2005 0.7L Copen
    Or buy a cheap bluetooth ECU reader from somwhere like DealExtreme, and get any number of iPhone and Android apps - that what I've done :)
     
  9. DaG

    DaG Copenworld Guru

    Joined:
    Jul 11, 2012
    Location:
    Sunderland
    Car(s):
    Copen 1.3
    :D
    I typed it on my phone and so was brief.
     
  10. DaG

    DaG Copenworld Guru

    Joined:
    Jul 11, 2012
    Location:
    Sunderland
    Car(s):
    Copen 1.3
    I've got an OBD code reader it's self contained though, doesn't send to a phone or other device
    The problem with these readers is they are only any use if the ECU has thrown up a fault code and lit up the engine management light. Mac1962 didn't mention the light was on so I assumed it wasn't.
     
  11. trustafox

    trustafox Copenworld Guru

    Joined:
    Nov 19, 2012
    Location:
    East Mids
    Car(s):
    Yes
    yes I assumed he hadn't either. Like number 6 I have a cheap bluetoother with phone app.

    As he's local, he could try mine if he needed to.
     
  12. mac1962

    mac1962 Copenworld Newbie

    Joined:
    Feb 22, 2014
    Location:
    Leicestershire, England
    Car(s):
    2004 Copen 0.7 litre Reg WV04 MZZ
    Last night, I plugged in my ODB2 dongle and paired it with my Android tablet. The revs dropped to around 740 rpm, no fault-codes were reported, and the fuel was in "closed loop" mode.

    There's probably some kind of intermittent fault, like something sticking or a leak in the fuel-intake system. Like Trustafox says, the ECU should take car of the idling speed and fuel/air mix. I'd expect that if there was an intermittent bug in the fuel-mixture loop, some kind of fault would be logged but maybe not.

    Also, if the car has a throttle cable, ( rather than just a potentiometer ) maybe it's not returning properly, but that only explains the higher rpm, not the rich fuel-mixture.

    I'll try logging my drive home from work. Maybe something will appear when I'm giving it a damn good thrashing.

    The exhaust pipes are very sooty, like a chimney. I need Dick van Dyke to dress up as a chimney-sweep and do his stuff.
     
  13. trustafox

    trustafox Copenworld Guru

    Joined:
    Nov 19, 2012
    Location:
    East Mids
    Car(s):
    Yes
    :eek: I'd advise to just concentrate on the driving.
     
  14. mac1962

    mac1962 Copenworld Newbie

    Joined:
    Feb 22, 2014
    Location:
    Leicestershire, England
    Car(s):
    2004 Copen 0.7 litre Reg WV04 MZZ
    ....with both hands on the wheel!

    I took the plastic cover off the engine for the first time at the weekend. The throttle cable was a little bit slack, but the return spring seems snappy enough. I took up the slack so that the accelerator pedal is slightly more instantaneous. Its all a bit tightly packed-in under the bonnet.

    I didn't see anything which might cause a rich mixture. When I have some more time, I'll check all the hoses and joints more thoroughly in case there's a leak or some perished rubber. ( OO-ER Mrs! )

    I'll get the car serviced in a couple of weeks time, when life isn't so busy. The garage's diagnostic software will be better than my 10 quid ODB2 bluetooth interface. Usually, there's some indication of the fuel-air balance but not in the Copen. It would be nice to know why the ECU "thinks" it needs a rich mixture......

    I'm not sure about leaving the ODB2 plugged in as I keep kicking it when using the clutch.
     
  15. TooCopen

    TooCopen Copenworld Member

    Joined:
    Aug 8, 2013
    Location:
    France
    Car(s):
    Copen 0.7
    Hello mac1962
    I see your car is same model as mine, 0.7 turbo :)
    I already observe the "high" rate of the idle with my car, and sent a post to have advice. Someone answered to me, saying that a such small engine need to run fast... I must say that it did not convince me :think:
    The normal speed, read on ODB, must be 750 +100/-50 rpm.
    But you need to check that your motor is a stable temperature, that no light is ON, and that all ancillaries, and specially Air Cond, is OFF.
    And I hope you will be quiet now with the rpm, as I was after checking conditions to have normal idle rpm.
    As 'trustafox' said, if the car is running well, don't worry...
    If not, and if the exhaust pipe are dirty, dismantle a spark plus and check its colour. If "Brown" it's OKay :)
    If black, you have to check if air filter is recent, if the engine consume oïl, if...
    Try to get an advice from a technician
    Hello to everybody on the site ;)
     

Share This Page