Stalling 328 when slowing down and it's not the clutch... | Page 3 | FerrariChat

Stalling 328 when slowing down and it's not the clutch...

Discussion in 'Technical Q&A' started by rob lay, Dec 8, 2003.

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  1. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
    Full Name:
    Rob Lay
    Thanks, I don't feel comfortable with the mixture screw. Even if I did it right, I'm going to pay Norwoods to use the sniffer and double check. I'm just going to live with it for now and get it fixed right in a few months. I'll go through this entire thread and list out all the suggestions, just as a suggestion. :)
     
  2. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    C'mon Rob,
    Divert a G from the Ferrarichat racing slush fund to James and he'll tell us what it is.....
    Enquiring minds want to know.
    :)

    Good luck
    rt
     
  3. SR Ferrari

    SR Ferrari Rookie

    Dec 1, 2003
    48
    Rob.
    If you lean out the CO screw that is adjusted with usually a 3mm T handle allen in a counter clockwise direction it will raise the idle,to compensate for the raised idle the large hex knob which is the air bi pass
    screw is usually turned in in a clockwise direction.

    To make the adjustment the mistakes that can be made are.
    (1)When the CO is adjusted it is important to block to adjusting port off each time you make a small correction and let the gas analizer reach its true value.
    By not capping off the port you are infact allowing a vacum leak through the air flow meter housing there for not establishing a correct Air fuel Ratio.
    Once you have established your correct CO value which should be measured pre cat and not post cat, "do not" set the value by placing the prob in the tail pipe when the motor is hot.
    You can then make the adjustment to correct your idle RPM.
    (2) Many cars leave the shop with this adjusting port open?
    (3) These adjustments are made with the motor at operating tempreature.
    (4)In the early days of adjusting AFR we used a multi meter like a fluke 33 disconnected the O2 sensor and read the flip flop value between .4 and .8
    MVolts to establish stoy or an AFR of 14.7to 1.
    The clutch adjusment has to be perfect usually the first sign of an incorrectly adjusted cutch is the pedal is stiffer than norrmal.
    With a new correctly adjusted clutch the pedal should be smooth and very easy to operate. If the clutch is not adjusted correctly it can bury the thrust bearing and overthrow the clutch.
    Kind Regards
    Wayne Hynes.
     
  4. DGS

    DGS Six Time F1 World Champ
    Rossa Subscribed

    May 27, 2003
    60,049
    MidTN
    Full Name:
    DGS
    If the problem only shows up when cold, that would tend to point to the aux air valve (and plumbing), the cold start injector, or the "warm-up regulator" aka "control pressure regulator".

    You can check the control pressure with a CIS pressure gauge, available from NAPA auto parts. The hot and cold control pressure graphs are in the 328 tech specs, which are in pdf form on the "private ferrari documents" site.

    If this appeared suddenly, it might indicate a connector issue. If the sensor connectors aren't making contact, the ignition timing might not be right, when cold. If the throttle position sensor isn't reading idle correctly, that will definately throw your idle speed off. That can be compensated, but probably only for warm, not for both warm and cold operation.

    Or both -- if the "thermo time switch" isn't conducting to the control pressure regulator, that could throw your control pressure off, in a temperature related way.

    Otherwise, sensor issues would show up as ignition timing glitches, which should appear on an engine analyzer scope. A mixture issue would be CIS or air feed.

    A vacuum leak anywhere past the AFM will throw the mixture off. But the 328 has way too much induction plumbing, between the aux air valve, the idle feed, the individual idle air tubes, et cetera ad going postal frustration.

    Of course, all that pretty much covers the whole flippin' system, so I guess that's not much help, beyond saying "check everything, piece by piece by piece".

    Anyone know a reasonably priced, fairly reliable psychic medium to channel devine intervention to find CIS problems? ;)

    It's a good thing these systems don't go wrong often, because when they do, it's a @#$% to find. Makes you appreciate OBD-II.

    Anyone at Norwoods have veedub experience? An Audi/VW wrench has probably seen far more CIS problems (by virtue of sheer production numbers) than Ferrari mechanics have.
    .
     
  5. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
    Full Name:
    Rob Lay
    Actually, the problem is only when warm. I think just because the fast idle keeps it from stalling.
     
  6. carlrose

    carlrose Formula Junior

    Nov 25, 2003
    321
    Hi guys,

    Just did a "chase-down" looking for vacuum leaks on my 1988 328. It's (honestly) not that bad. Here's the parts:

    1. Check the fitting on the lower metering unit (large "C"-tube) that the 19mm hose leads off from to be tight.

    2. Plenum inputs include: power brake hose, microplex (LH), emissions cannister (RH).

    3. Throttle body includes WUR (larger hose/accessible) and vacuum hose for air injection system (underneath)

    4. Under the plenum (and removing this is a challenge) is a "spider" tube apapratus with inputs on LH side from oil/air separator (smaller hose) and induction (19mm hose aforementioned). Then there's a small piece of vacuum hose to each individual intake runner and at the end an "L-shaped" piece to the CS injector.

    If memory serves me right that's it. I found good (read tightly-fitting) small vacuum hose at MB/Porsche dealer or email me & I'll send you a piece of the size to find. Replaced several others with braided black hose standard (nonmetric but close) from NAPA - "Weatherhead" variety. Now the thermotime switch is buried under the plenum & if I ever remove again will simply replace. Oh, there's also the plenum-to-intake runner gaskets & then runner-to-cyl head gaskets.


    Let me know if I can help further: [email protected]. Thought about writing this one up also.

    :) Carl
     
  7. davehelms

    davehelms F1 Rookie

    Jan 3, 2004
    4,629
    Full Name:
    Dave Helms
    Pull the panel in the rear trunk that contains the O2 ECU and the protection relays. On more than one occation I have found the ECU contacts growing hair. The antenna drain hose falls off and it drains directly into the ECU. A soft brass brushing of the contacts with contact cleaner should do. Most every time I have a 328 intermitently starts stalling when it is warm, this is where the problem is found.
     
  8. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    17,564
    Savannah
    geeze.............. great thread but LONG LIVE CARB CARS!!!!!!!!!!!!
     
  9. Caruso360

    Caruso360 Karting

    May 1, 2003
    203
    Next time, let's just skip to Helm's!
     
  10. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
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    Rob Lay
    Now that wife is making money for first time in over 3 years, I have the 328 back to Norwoods to get it fixed right.

    I can't explain fully, but the control pressure was way off and Ken knows the warm-up regulator installed on mine is the wrong one. So far the best price I've found on one is $487. Hopefully this will be the extent of fixing my problem.

    Part number I need is 121743.
     
  11. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
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    Russ Turner
    This is a legendary thread.....
     
  12. dm_n_stuff

    dm_n_stuff Four Time F1 World Champ
    Lifetime Rossa Owner

    Dennis McCann has one for $375.00

    http://www.allferrariparts.com

    Just search by the part #
     
  13. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
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    Rob Lay
    Awesome!!! I owe you $100 worth of beers. :)
     
  14. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
    79,143
    Houston, Texas
    Full Name:
    Bubba
    No SH-T!

    I don't even HAVE one of those thingies.........
     
  15. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
    79,143
    Houston, Texas
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    Bubba
    Jus' 4 spittin' nasty webers and a charcoal canister.....

    oh. wait, I think I see that, rolling in the road, in the rear view mirror!
     
  16. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
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    Rob Lay
    I know I have been a tech tease for 3 months now, but the final resolution is in!

    The wrong warm-up regulator was in my car. I got the correct one in from Dennis McCann, thank you dm_n_stuff! Saved me $100 vs. all other sources. I also get to make some money selling the other one or at least getting some core money.

    Ken at Norwoods installed the new regulator and made the proper adjustments and presto, car runs perfect now.

    Thanks everyone for your suggestions, I printed them all off and gave them to Ken, but Ken was saying it was the warm-up regulator from the very beginning.

    Whew, I got out of the entire thing cheap too.
     
  17. Eric308gtsiqv

    Eric308gtsiqv Formula 3

    Nov 26, 2001
    1,955
    Orange Park, Florida
    Full Name:
    Eric Eiland
    Glad to hear that the problem's solved, Rob...and that you're back on the road again!

    Will definitely save this thread for future reference too.

    BTW, had a similar situation with the TR (stalling when approaching stop, clutch depressed, etc.) -- but the problem mysteriously went away after a couple of drives. Good thing too, as it's a real trick downshifting, working the clutch, pressing the brake, and working the accelerator to keep the revs up...ALL AT THE SAME TIME :D
     
  18. rob lay

    rob lay Administrator
    Staff Member Admin Miami 2018 Owner

    Dec 1, 2000
    59,407
    Southlake, TX
    Full Name:
    Rob Lay
    LOL - I'm a good heal-toe'er, but this technique took me a little bit to master. :) It was kinda fun after I figured it out though.
     
  19. dm_n_stuff

    dm_n_stuff Four Time F1 World Champ
    Lifetime Rossa Owner

    Does that mean I get a free www.ferrarichat.com t-shirt and mug???

    either way, my pleasure, glad you're back on the road.

    Dave
     
  20. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    Rob - hooray on getting away inexpensively on the car!
    This has been a great story to follow - many thanks.
    Have fun driving!
    Russ
     

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