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WUR question

Discussion in '308/328' started by lostbowl, Jun 30, 2010.

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  1. lostbowl

    lostbowl Formula 3

    Apr 30, 2009
    1,246
    Michigan
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    Tom
    #1 lostbowl, Jun 30, 2010
    Last edited: Jun 30, 2010
    I'm still having a problem on cold starts even though it runs great and starts fine when warm or hot. My question is this; if the system pressure and cold control pressure and hot control pressure are all book spec (to the bar) and the heating element is also operating as it should-------------------- can the WUR still create a problem? My main issue is that upon cold start I must hold the peddle 1/2 down and then feather it when the revs get too high. The engine stumbles badly during this time period, sometimes popping through the exhaust and some pops from the air sensor .Once the light goes out all is well and the idle holds at 1K. I have replaced the AAV and the cold start air valve is fine. In addition I have disconnected the cold start system completely and then re-connected and then connected it with a 30% restriction and none of these adjustments make a difference. ANY thoughts will be appreciated. I have very little hair left! Lostbowl

    PS I have checked every vacuum hose and sprayed starting fluid everywhere with no change during idle.
     
  2. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,198
    Seattle, Washington
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    Cliff
    #2 CliffBeer, Jul 1, 2010
    Tom, have you already checked to see that the AAV and cold start valves are getting the right signal to operate at the right time? In other words, if you're replaced the part but there seems to be an operating fault (poor cold start) then checking the electrics associated with these parts makes sense to do.

    Good luck and persist!
     
  3. lostbowl

    lostbowl Formula 3

    Apr 30, 2009
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    Tom
    #3 lostbowl, Jul 1, 2010
    Cliff,
    I have checked and re-checked all systems. The interesting fact is that the cold start problem remains the same with/without the cold start system. I can't seem to find a component that makes a difference in how it acts. It truely is acting as if there is an air leak but I cannot detect one. I would like to find a source for CIS parts ( gaskets o-rings etc.) so I could take the FD apart and check it. The system is not that complicated but all things must be in sync. Still on the low end of the learning curve. Tom
     
  4. fastradio

    fastradio F1 Rookie
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    Apr 26, 2006
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    David Feinberg
    #4 fastradio, Jul 1, 2010
    Last edited: Jul 1, 2010
    Tom,
    Getting back to basics, have you checked the injector spray patterns and opening pressures? Also, where are the mixtures levels? And...does the sensor plate move freely throughout its entire range, without any binding? I'd check this with both a cold engine and then again, when warm.

    Best,
    David
     
  5. lostbowl

    lostbowl Formula 3

    Apr 30, 2009
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    Michigan
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    Tom
    #5 lostbowl, Jul 1, 2010
    Fastradio,
    When I was putting things back together I purchased and injector tester and all spray patterns were spec and the opening pressures are right on. The sensor plate had to be re-centered and the position had to be adj. by means of the guide pin. I have adj. the mixture from 1.5% CO up to 4.5% CO and there is no change. I cannot find a vacuum leak and my ignition is strong and consistant. I have just e-mailed Mr. Fletcher for his opinion. The onlt thing for sure is I have very little hair left! Throwing in the towel is not an option.
    Thanks in advance for any imput.
    PS the mind boggler is that I have not been able to effect any change no matter what I do!
     
  6. st@ven

    st@ven F1 Rookie

    Aug 4, 2008
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    Steven
    #6 st@ven, Jul 1, 2010
    the cold start system is not doing much anyhow. Quite some people do have non functioning systems without knowing it. The car will start without it too if temperatures are pretty within normal range
    You're problem is probably not initiated by a fuelproblem. But to make sure I would focus on the pump.

    Anyway, I would check the ignition first.
     
  7. lostbowl

    lostbowl Formula 3

    Apr 30, 2009
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    #7 lostbowl, Jul 1, 2010
    Steve, The pump checks out at 5.2 bar and early on I had a hot start problem and replaced the accumulator and solved that issue. The ignition is strong and consistant. The system holds pressure for hours. I'm still scratching my head. Tom
     
  8. Robz328

    Robz328 F1 Veteran
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    Mar 16, 2009
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    Rob Hemphill
    #8 Robz328, Jul 1, 2010
    Last edited: Jul 1, 2010
    From what's being said, all seems to be normal for the components.

    Question: what light goes out when the engine's warm?

    Notes:
    1. The air sensor, when closed, is supposed to allow a residue of air through the gate area at idle (not associated with the AAV). Thus it should not "create a seal" when closed.

    2. You could still have a stuck-closed AAV.

    3. Pull spark plugs and check for excess fuel burn (black and sooty), oil (black/brown and oily), and coolant smell. For example, a small bit of coolant leakage into the spark chamber could foul the ignition until it "cooks off" at warmer temp (same for water/condensation in the fuel).
     
  9. st@ven

    st@ven F1 Rookie

    Aug 4, 2008
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    Steven
    #9 st@ven, Jul 1, 2010
    indeed the air sensorplates setting could be to high. Check this one, it should be just below the edge of the smallest gotru (obviously, when the engine is not running)
     

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