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Poor Running Condition

Discussion in '308/328' started by t3thomas, Jan 8, 2010.

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  1. t3thomas

    t3thomas Formula Junior

    May 9, 2008
    427
    North Carolina
    Full Name:
    GThomas
    #1 t3thomas, Jan 8, 2010
    My '84 QV recently started running very poorly and although I've taken apart the WUR and AAV to check for problems the same condition remains. It will start fine and warm-up perfectly, but once it reaches operating temps it smokes and will barely run. Any ideas on what else to check?
     
  2. santacruzn

    santacruzn Rookie

    Nov 10, 2003
    44
    Santa Cruz, CA
    Full Name:
    Bill Grace
    #2 santacruzn, Jan 8, 2010
    Hi,

    I recently had a somewhat similar problem with my 328. I checked this board and found a post on the fuel injection relay coming loose. In your trunk on the passenger side is a small panel that has the fuel injection computer and some relays mounted on it. On my car the long relay was out of its socket by 3/8 of an inch or so. I re-inserted it and tie wrapped it in place and all was well again.

    Its worth a look see....

    Bill
     
  3. fastradio

    fastradio F1 Rookie
    BANNED Professional Ferrari Technician

    Apr 26, 2006
    3,664
    New England
    Full Name:
    David Feinberg
    #3 fastradio, Jan 8, 2010
    What problems might one see by merely taking these components apart, other then perhaps something blatantly obvious?


    What is your "hot" fuel pressure?
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #4 Steve Magnusson, Jan 8, 2010
    Is your 308QV an unmodified Euro (still K-Jet without Lambda) or has it been modified to meet US standards (some sort of Lambda/O2 sensor modification added on)?
     
  5. t3thomas

    t3thomas Formula Junior

    May 9, 2008
    427
    North Carolina
    Full Name:
    GThomas
    #5 t3thomas, Jan 8, 2010
    Steve:

    My car is an unmodified euro version w/o Lambda. Also, for the previous posts, the 308 does not have the same injector relay inthe trunk as the 328 I believe, at least mine doesn't have any relays in the trunk. Also the reason, I took apart the WUR was at the advice of a local F mechanic who said it might be causing problems w/ slow warm ups and cleaning could possibly help. The AAR was to see if it was functioning properly (the freezer and oven test, which it passed).
     
  6. speedy

    speedy Formula Junior

    Oct 18, 2005
    625
    Plano, TX
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    James Gardner
    #6 speedy, Jan 8, 2010
    If it's warming up fine and then "smoking" (I'm assuming it's not oil smoke), they you may be running really rich.

    Did you try running your car with the WUR unplugged? The WUR may be stuck open and dumping fuel in to the plenum after the car has warmed up. The extra fuel could foul your plugs and make it run rough.


    Just throwing it out there.


    Good luck fellow Euro-man
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #7 Steve Magnusson, Jan 8, 2010
    Then you really don't have much else to else to look at other than checking the warm control pressure from the WUR as David suggested (since you say that it runs fairly well when cold, this implies that the cold control pressure isn't too wacky -- but you'd still measure/check that too -- and the regulated supply pressure).
     
  8. t3thomas

    t3thomas Formula Junior

    May 9, 2008
    427
    North Carolina
    Full Name:
    GThomas
    #8 t3thomas, Jan 16, 2010
    Finally pulled myself away from my other cars and checked system pressures you guys mentioned. The results certainly were;

    Cold Control- 40 psi
    Primary- 73 psi
    Start Presure- 50 psi then a gradual drop to 25 psi when fully warmed up
    Warm Control- 50 psi
    Residual/Rest- 40psi at shut off and 40psi at 20 min.

    After reading some other posts, It appears the running pressure at full warm up should be considerably higher, perhaps in the 75 psi range? Do these results indicate a malfunctioning control regulator (WUR)? I've also read where disassembly of the WUR requires it to be re-set to Bosch specs, but don't understand why if no modifications were made to it.
     
  9. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,345
    #9 Paul_308, Jan 16, 2010
    Last edited by a moderator: Sep 7, 2017
  10. t3thomas

    t3thomas Formula Junior

    May 9, 2008
    427
    North Carolina
    Full Name:
    GThomas
    #10 t3thomas, Jan 17, 2010
    Paul:

    It appears that the pressures are within the ones shown on the posted page;

    Cold Control- 40 psi, 2.75 bar
    Warm Control- 40 psi, 2.75 bar
    System Presurre- 73 psi, 5.0 bar

    But I don't beleive the presurre should be dropping as the car warms up, or that when it is fully warmed up the presurre should be at 25 psi, 1.7 bar. What does this point to as being faulty?
     
  11. 308GTS

    308GTS Formula 3

    Dec 27, 2001
    2,223
    TN
    #11 308GTS, Jan 17, 2010
    From what you have said you WUR isn't working. Your cold control should be somewhere around 20-25 psi cold and gradually raise until it reaches warm control around 45-50. Once warm is shouldn't drop at all. From what you have written I would replace or rebuild the WUR.
     

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