405 Mi16 ECU plug?
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  1. #1
    Fellow Frogger! pips's Avatar
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    Default 405 Mi16 ECU plug?

    Hi All,

    My wife's bother happens to run a workshop.

    He also happens to have just bought a Computer scanner from the Snap-On man. I also noticed it happened to have the plug module for a Pug.

    Now, I've scoured the workshop manual, and the user manual (just in case it mentioned it there). Where is the plug that you plug the scanner into, to get the errors and other information.

    My mind has gone blank as to what the issue with this car is. I've replaced fuel lines, filters, spark plugs, leads, vacuum hoses, etc. And yet it still runs fine, then when warmed up to road running temps, it idles at 400RPM and sometimes dies.

    I'm hoping this scanner will alteast tell me something, because all I can think of now is that the ECU is bung. Which sounds expensive already.

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    Cheers
    pips
    Ever wonder why Mad Scientist talk to themselves? They know others just wouldn't understand.

    The software said "Windows 98 or better". So I installed Linux.

    1990 405 Mi16

  2. #2
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    The diagnostic connector on yours is inside a black plastic box in front of the RHS strut tower. It's a green, standard Bosch style two pin connector, like the ones all over the engine.

    However, the idling issue could well be the idle stepper motor which is a common issue. This is the thing like an aluminium can sited on top of the inlet manifold, with a rubber hose connected to each side. It has a grey connector attached to it. This is essentially a servo controlled valve which allows air to bypass the throttle according to feedback from the crank sensor (which tells the ECU how many revs the engine is doing). It finely controls this air, and the injection compensates the air with the appropriate amount of fuel, hence, the idle is usually finely controlled through this closed loop system.

    However, when the idle stepper motor bungs up a bit, it doesn't move smoothly or at all. Some people have had success with cleaning them out and then lubing with silicone spray. There has been a thread on this on AF.

    By the way, you don't need the diagnostic computer - the fault codes can be read by the number of flashes of the K-light on the dash. Do a search on 'K-light'. There was a thread on this in the last couple of days, where I posted a link to a previous thread about the issue.

    Stuey


    2003 PEUGEOT 206 GTi

  3. #3
    Fellow Frogger! pips's Avatar
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    Cheers, I shall search for the K-light thread.

    I cleaned out the idle motor when I first got the car, as it would sit in traffic revving at 2,000RPM.

    But these days, it sits on 1,500RPM when cold (warming up), but after it has heated up nicely, like a good 30 mins after driving. The revs drop down like I mentioned earlier. Every single time. Between this time, it runs spot on, ever since replacing the spark plugs and HT leads, it idles on 850 RPM and smooth. But then drops off again.

    Could the idle motor have anything to do with this or would it be a sensor? And what sensors in particular would effect idle speed? o2, Coolant temp, Oil temp, air temp? or all, or more?

    I checked the K light, it flashes * pause * *, Signifying the number 12. then I ground the wire again (for 3 seconds) and get 11 (* pause *)

    So, there are no errors in that department.

    Is there a way to check the operation of the idle motor? like removing it and putting 12 volts to it or something? Or would that kill it?

    Cheers
    pips
    Last edited by pips; 19th October 2005 at 04:06 PM.
    Ever wonder why Mad Scientist talk to themselves? They know others just wouldn't understand.

    The software said "Windows 98 or better". So I installed Linux.

    1990 405 Mi16

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    Hi pips,

    didn't Paul when getting your timing belt notice this problem?!? I wouldve thought that would be a good time to check it out since he knows what to do (well, so far I've had no probs, though i dont like the recent problems you've been having with him re: oil filter and rough engine)
    '93 405 Mi16 Series2 Sold!

  5. #5
    Fellow Frogger! pips's Avatar
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    I told him about it, but he didn't say much (Meaning, nothing).

    He did mention that my Accessory belt tensioner was shot. Though when I talk to pug parts places, they tell me there's two. One metal one and one plastic one with a large alloy mounting/tensioner unit attached.

    Not sure which one Paul was referring to. But it's costly. Probably worth replacing both, but can't afford it at this stage. And the car barely gets used, until I sort it all out.

    pips
    Ever wonder why Mad Scientist talk to themselves? They know others just wouldn't understand.

    The software said "Windows 98 or better". So I installed Linux.

    1990 405 Mi16

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    It sounds like something that's heat affected, but I can't think what.

    The Motronic ECU controls very small changes in idle through timing adjustments (the bigger ones being made by the idle stepper) as well. The inputs for both forms of idle control are revs and engine temp (and closed throttle I think).

    Stuey


    2003 PEUGEOT 206 GTi

  7. #7
    Moderator Alan S's Avatar
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    Take a look under the section where the butterfly sits and look for a plug and see if that's been pulled out. If not, take a look at this.

    http://www.rwbsmith.plus.com/citroen2/Injection_system/

    I think you'll find that is for the series one without a Catalytic converter, but may point you in the right direction.
    I have today had the hoses off the filler cap on a Tri 122 and it carried on like that, just idled so slow it stopped, so look for air getting in where it shouldn't. They also reckon if the dipsticks stuffed it will affect the idling badly. Is it a tight fit in the tube?

    Alan S
    If it ain't broke, use a 12" shifter.....that usually does the trick!!

  8. #8
    Fellow Frogger! pips's Avatar
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    Butterfly, meaning that throttle body after the air filter and MAP sensor?

    Cheers
    for the link. I shall have a read of the pdf's and see what I can come up with.

    The dipstick on mine is a little chatty. That may well be the issue. I'll try blocking it with something else today and see what happens.

    Also, just thinking back (and I'll check this as well), the filler cap housing is cracked a little.

    I hear these are not cheap.

    Cheers
    pips
    Ever wonder why Mad Scientist talk to themselves? They know others just wouldn't understand.

    The software said "Windows 98 or better". So I installed Linux.

    1990 405 Mi16

  9. #9
    Moderator Alan S's Avatar
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    Quote Originally Posted by pips

    Also, just thinking back (and I'll check this as well), the filler cap housing is cracked a little.

    I hear these are not cheap.

    Cheers
    pips
    One of these was on eBay a week or two back for $10 I think a guy at the Gold Coast who sells a bit of Pug stuff mainly brake rotors, could have had it. Might be worth a look and see if he still has it in his 'eBay shop'


    Alan S
    If it ain't broke, use a 12" shifter.....that usually does the trick!!

  10. #10
    Fellow Frogger! pips's Avatar
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    Thanks AlanS. I'll look into ebay.

    Cheers
    pips
    Ever wonder why Mad Scientist talk to themselves? They know others just wouldn't understand.

    The software said "Windows 98 or better". So I installed Linux.

    1990 405 Mi16

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