Using Logic?

Discussion in 'Technical' started by coolum, Mar 24, 2014.

  1. coolum

    coolum Member

    I have had an AFM problem (wanted section) which was identified by Rollin and the car ran well with a swapped AFM from a donor vehicle.

    As I'm seeling the car and the buyer wants it last week, I got the fastest delivery AFM which was an aftermarket AFM - new from brissie. - great.

    car was picked up and ran great on the highway but by the time I got back to sunny coast the car was idling erratically.

    it was deemed to be an iacv valve, so I have now replaced this valve, but the car is still idling with 'pulsing' characteristic.

    Back to square one, could this be an AFM problem (erratic Idle) as it also seems to be better when the aircon is on and worse to the point of stalling when the aircon is off.

    with aircon off it revs up to 1.2k then drops to 0.4 then 1.5 to .05 then 1.0 to .0.7 then repeats then eventually drops so low it stalls..

    It should have been due to the IACV but the replacement is exactly the same (not better or worse) which would lead to logically rule this out?

    This car is a fully maintained stock vehicle with everything in perfect condition (except one bloody part )

    Any clues plz?

    Steve
     
  2. Shane001

    Shane001 Well-Known Member

    It's probably the aftermarket afm. See if you can get the other good one and test it again.
     
  3. zx299

    zx299 Well-Known Member

    It IS the aftermarket afm......

    Aftermarket afm's are ALL garbage !!!! They look good but have absolutely no consistancy in their outputs.

    The market is crawling with 'fake' JECS afm's, but they are easy to pick because the ID sticker is a poor imitation of the oem item. Stick with oem or Bosch and you can't go wrong.
     
  4. munted

    munted New Member

    Just out of curiosity what was your idle issue before the new afm?
    As I have the exact symptoms you describe above, but only whilst car is between 40-80 deg c.
     
  5. coolum

    coolum Member

    Thanks,
    That makes me feel more confident in chasing - abd its what Niall and logic would suggest.
    TY
    Steve
     
  6. coolum

    coolum Member

    Its complicated, basically the car was running but with no power and had to be towed to Rollin in Brissie, the pulsing erratic nature was not really evident - He swapped out parts till He isolated the AFM as the issue.
    Niall did not notice any issues and neither did I in Brissie it was only after a run back to the sunny coast did the problem really surface.
    It seems like it is the AFM at this time and I am hopeful the 'real thing' will solve the issues.
    I intend to return the aftermarket AFM ASAP and if they give me the money back then all good otherwise I will resort to unhappiness (and possibly vilification).
     
  7. munted

    munted New Member

    Please do post a result when your new afm comes in. I hope it solves your problem.
     
  8. coolum

    coolum Member

    will do!
    the AICV was for all intents and purposes a possibility also but this changed nothing.
    Is yours effected by the use of Aircon as mine (fluctuations in revs) is currently reduced by its use.
     
  9. munted

    munted New Member

    yeah if i turn my ac on i get a constant 1300 rpm.
    its just whilst its warming up it goes 1100 - 800.
    but weirdly. itll go 1100 ish and sit there for 4 seconds or so then drop to 800 for 2 seconds. and its not predictable either as the times vary at the rev ranges. sometimes 10 seconds, sometimes 2 seconds.

    im planning on pulling the iacv unit off and cleaning and checking the resistance soon, just been overloaded with work and family life.

    edit*
    That damn sig pic is doing my head in.. :D
     
  10. coolum

    coolum Member

    They don't make cars like that any more.

    There could be a reason for that.

    Perhaps this is the result ('Chinese whisper') of a Russian built (using cold war industrial espionage) German Daimler design.
     
  11. 90TTZ

    90TTZ Back From The Dead

    I replaced a failed AFM for a customer a little while back with a non genuine item. Basically the idle was eratic with his 3A Pod Filter, put an Apexi Power Funnel filter on it and the idle settled out.

    The aftermarket AFM's I found are extremely sensitive at low air speeds and turbulence. Try running the engine with no air filter and see if the idle improves.
     
  12. coolum

    coolum Member

    NEW AFM Rectified the problem and car is running like a top.

    Its hard to know when sensors go - and the biggest problem is you end up replacing a stack of stuff that makes no difference - apart from the fact that it now means there is less future things to go wrong as you have replaced a crap load of stuff with new bits to get to the bit that actually fixes the problem.

    You wouldn't want to own one of these things if you don't have a few bucks to throw at it is the bottom line

    thanks one and all for your help with this problem .. all hints and tips and suggestions much appreciated.

    steve
     
  13. Shane001

    Shane001 Well-Known Member

    I think the key message is with critical sensors, you have to buy genuine. Aftermarket just doesn't cut it. The risk isn't worth the few dollars you might save.
     

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