Peugeot 406 hesitation

Discussion in 'Peugeot 406' started by Tonyh, May 7, 2005.

  1. Tonyh

    Tonyh Guest

    Hi, Iv’e a problem with Peugeot 406 2 ltr hesitation etc, there’s
    always been a problem with uneven running when under oxygen loop
    control upto 3000rpm. Engine is EW RFR type Magneti Marrelli ECU. A
    guy who knows a thing or two about peugeot’s assured me it was a coil
    pack, which I replaced, no better. But stayed with it replacing odd
    bits when I had time. Eventually it failed emission tests, so I took
    it to main agents, who diagnosed misfire cased by guess what! the coil
    pack. Still failed MOT so replaced CAT, passed ok but still misfires,
    so decided to try again myself, before the next CAT goes, (this is the
    second replacement).
    Hooked injectors and oxy sensor up to oscilloscope set up peg in
    throttle to 2250 rpm and took a few observations.
    Injector on period dithers about 3ms (under loop control)
    No of high counts from oxy sensor = 85 per minute
    Voltage from throttle position sensor = varies slightly between .89v -
    .9v
    After some time at this state the revs drop to approx 1200 rpm,
    readings then as follows.

    Injector on period dithers about 4ms (under loop control)
    Oxy sensor switching, but not counted, it looks normal.
    Voltage from throttle position sensor = .893v

    Why should injector see 4ms as the correct fuel dose to produce a
    switching oxy sensor?
    The idle valve has been renewed, (not faulty). But I cant work out
    what its position might be set at, or why it should want to be at a
    position other than the 2250 rev spot.
    Any help would be appreciated.
    Tony


    :(
     
    Tonyh, May 7, 2005
    #1
  2. Hi mate these engines are a bag of shit (ew10j4r) the uneven idle is common
    ....usual causes are hydraulic tappets (can be diagnosd with a scope and amp
    clamp from cold on batt lead) injectors (prob test last of all for
    delievery and distribution ) coolant temp sensor , throttle body remove and
    clean out and replace rubber seal, manifold absolute pressure sensor, prob
    need a bit more info for hesitation .test these items mentioned never just
    replace, you have a oscilloscope get it hooked up and ripping , you seem
    pretty switched on ... all the best mark (peugeot master tech)
     
    MARK BANKS via CarKB.com, May 9, 2005
    #2
  3. Tonyh

    Tonyh Guest

    Hi Mark thanks for the reply. As soon as I get some time to spare I’ll
    try and tick a few suspects off the likely list.
    Tony
     
    Tonyh, May 12, 2005
    #3
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