Engine shuts down | FerrariChat

Engine shuts down

Discussion in '308/328' started by lonnie77, Oct 10, 2012.

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  1. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    After driving about 10 mi. or when the engine temp is above 170 deg the engine will start to act as if it is running out of fuel until it shuts down. Once the engine cools off below 160 deg it will start. I checked for fuel at the CSI and at an injector after it shut down and I have fuel and pressure so I don’t think it is vapor lock. The accumulator, filter, fuel pump and O2 sensor are not very old. The only sensor I see that may cause this is the thermal switch at the expansion tank. Can anyone help me with this or have a suggestion?

    Thanks.
     
  2. Crowndog

    Crowndog F1 Veteran
    Rossa Subscribed

    Jul 16, 2011
    7,042
    Fairfield,Pa
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    Robert
    Did you happen to notice if the engine quits when the fans come on or not?
     
  3. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    No I did not. I was to busy dodging traffic hoping to get into a parking lot. It will start to miss and buck then shut off.
     
  4. hawaii50

    hawaii50 Rookie
    BANNED

    Aug 27, 2012
    48
    its vapor lock, believe me. do you have a stock exhaust system? Are your cats clogged raising the heat under the car. I would test the fuel preassure
     
  5. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,035
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #5 Steve Magnusson, Oct 10, 2012
    Last edited: Oct 10, 2012
    One easy diagnosic step you can take on the fuel side is to confirm/deny if the frequency valve is buzzing when the problem occurs -- it should always be buzzing whenever the engine is running -- cold or warm (and you would still have fuel pressure if it wasn't buzzing, but the engine would be very, very lean probably to the point of not running).

    Don't see how the coolant thermoswitch in the expansion tank could cause bad running -- even if (wrongly) stuck closed when warm (as it should be when cold), it would just force the injection system to run open-loop.

    (Of course, you could still have an ignition problem or a WUR problem or ?)
     
  6. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    The WUR has a thermo time switch attached to it. Anyone know what this device does? The problem seems to be temperature related. The engine runs great as long as it is below 160 to 170 degrees. It had a vapor lock problem a year ago were it would not start after I turned the engine off when it was up to temp and on a hot day. The slow down light flashes or stays on all the time even when the engine is cold. The cat has never been changed and the mileage only shows 67000 mi. I‘ll check the cat temp today.
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,035
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #7 Steve Magnusson, Oct 11, 2012
    Last edited: Oct 11, 2012
    Not sure what you mean by this. The WUR has an internal resistive heater -- but it is a "stupid" device that is just always "on" and the WUR can also absorb heat directly from the enigine (so even if the internal heater is broken the WUR will still eventually get warm).

    One easy thing to try here is to just unplug the O2 sensor when warm and see if it runs better. O2 sensors do go bad or a fault in the air injection system can "fool" the O2 sensor. By unplugging the O2 sensor (the single wire, not the 2-pin heater plug), the injection system resorts to running in the "cold" (open-loop) mode which you report is OK. If warm runability did improve markedly with the O2 sensor unplugged, then you'd know better where to look for the fault.
     
  8. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    I have tried disconecting the O2 sensor and I just installed a new Bosch O2 sensor. Looking at the schematic item #107 is the thermo time switch.

    [​IMG]

    I just went for a test drive and the slow down light made a liar out of me. It was off until the engine was warmed-up then it would flash or stay on for a few second. I drove about 1 mi before it started bucking as if it was running out of fuel. I tried to check the cat temp but my probe would not go that high.
     
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,035
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    #9 Steve Magnusson, Oct 11, 2012
    Last edited: Oct 11, 2012
    Yes, item 107 is the thermo-time switch, but the WUR is not "attached to it" in any functional way. The thermo-time switch controls the cold start injector. During warm-running, you can just unplug the cold start injector if you have doubts about the thermo-time switch operation (but if it was wrongly stuck closed, and continuously firing the cold start injector, that would muck up cold-running too).

    During the bad warm-running, and it had no effect?

    Definitely a bad sign -- but can be caused by excess fuel or missing ignition. Have you given the ignition system a through inspection (pin hole in extenders, etc.)?
     
  10. Crowndog

    Crowndog F1 Veteran
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    Jul 16, 2011
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    Robert
    I was thinking a short in the fan circuit that is activated when the fans go on but I suppose a fuse would blow first before causing ignition problems.
     
  11. Euro Quattro

    Euro Quattro Formula Junior

    Apr 20, 2005
    344
    Vancouver
    Full Name:
    Kent
    Mine did the exact same thing & all it was is the fuel pump fuse, I pulled it out & it fell apart in my hand...cheapest repair I ever did on th car.
     
  12. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    Yesterday I was close to were they sell the test pipes so I bought one. Today I removed the cat and looked through it and it was not clogged but I installed the test pipe anyway. It’s a little louder and it added a few more horses (runs great I impressed a few people) plus it runs a little cooler. Not cool enough to keep the engine from shutting down. As soon as that happen I checked for fuel at the injector and maybe three drops dribbled out. Not the same pressure I saw the other day, then I checked for fuel before the distributor and same thing. I disconnected the O2 sensor and it would not start. Someone stopped and wanted to talk about the car and after that it had cooled off enough that it started and I drove it to the house. As I was parking the engine started to shut down again so I popped the hood and grabbed the frequency valve and it vibrated until the engine stooped. I checked the temperature and 300 deg F was the highest I saw anywhere and at the thermostat it was 140 deg. I don’t think it is the fuel filter but I will check it and see it fuel isn't passing through the accumulator and make sure the fuse is good and the relay is ok. I see how the WUR item #139 not #138 connects to the fuel pump just not how it controls it I guess that is done in the distributor. But I can tell “exactly” when it will shut down by looking at the water temp gauge in the instrument panel every time.
     
  13. ME308

    ME308 Formula 3

    Nov 5, 2003
    1,542
    Munich, Germany
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    Michael
    just a quick thought "out of" the CIS box ...

    did your tach evtl. act up before the engine shut down ?
    (loosing rpm signal)

    your engine has one rpm sensor and one tdc sensor for both cyl. banks -
    (as opposed to a 308 which has one rpm sensor and one tdc sensor for each bank)

    sensors can fail either completely or erratically depending on surrounding(engine) heat
    the engine will shut off always exactly after a special temperature is reached -
    and starts as soon as it has cooled down ... until the temp is reached again

    while in a 308 you could limp home on only one bank (not recommandable if you still have cats), on a 328 - if either sensor fails - engine stops
     
  14. mike996

    mike996 F1 Veteran

    Jun 14, 2008
    6,685
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    Mike 996
    "it added a few more horses (runs great I impressed a few people) plus it runs a little cooler."

    Well if it runs cooler and has more HP, the cat was clogged to some extent. Objective dyno tests from a variety of sources show that there is no noticeable difference in power (or eng operating temp) between a modern cat and no cat on a street engine. John Lingenfelter - famous chevy motor builder - has published several such tests. In one, with a 700HP big block competition motor, the best he could get out of a cat/non cat was a 9 HP increase without the cat, doing all possible tuning adjustments to maximize the the difference.

    Doing it on a stock engine produces nothing IF the cat is in like-new condition. Admittedly, one can argue that a cat can clog where a straight pipe cannot so eventually, the straight pipe might produce more power than a cat of the same age.
     
  15. tepps

    tepps Karting

    Oct 15, 2010
    103
    Buffalo NY
    Full Name:
    Tom Tepas
    you have to determine if the engine shuts down due to no spark, or no fuel. You will need some test equipment that you can hook up with the WUR to determine your control fuel pressure..If you have constant, correct fuel pressure, and you can force the fuel injectors to spray by pulling up on your throttle plate (CIS fuel distributor). Then move on to your spark diagnostics, from battery to spark plugs. I suppose if the engine shuts down and wont restart for 5 or 10 minutes you might be able to pull off an intake hose and spray in some starting fluid to see if it will fire then.Spark or fuel ?? then report back to forum for further help.. I think you are starting to get a little off track in your diagnosis.
     
  16. lonnie77

    lonnie77 Karting

    Feb 17, 2011
    140
    Kennedale, Texas
    Full Name:
    Lonnie Harrison
    I want to thank everyone that participated in “guess my problem”. I know I’m not very clear in stating everything that is happening and normally I‘m fighting more than one problem. The problem was due to trash left over from the old accumulator. It was not in the new main filter but the small filter at the fuel distributor and the WUR. Once I cleaned them the engine would run and not shut down.
    The cat was not clogged I could look through it and see perfect square holes. The cat is twice as big as the test pipe and is full of ceramic that holds heat. Without the ceramic causing back pressure the engine will reach higher rpms quicker and HP will increase that’s why you use headers and a high flow cat.
     
  17. Faber

    Faber Formula Junior

    May 5, 2011
    954
    TX Hill Country
    Full Name:
    Tom G.
    Where is this "small filter at the fuel distributor and the WUR"? Thanks for any expertise.
     
  18. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
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    Brian Crall
    There isn't one. There is a screen in the warm up regulator but in my experience if it has debris it is just a signal the warm up regulator needs rebuilding.
     
  19. climb

    climb F1 Rookie

    Sep 19, 2006
    4,866
    Atlantic Beach Fl
    Full Name:
    Stuart K. Hicks
    I have a 1980 gtsi that will buck like that at higher rpms but doesn't cut off. Feels like a boat when it's motor is trimmed too high in the water. Almost a cavitation sound. Only happens on warm or hot days. I could run it all day in 65 degree temps and it would never happen. On an 85 degree day it will happen like clockwork about 5 minutes after car reaches full temp on the gauge.

    Wondering how you figured it was debris in the accumulator..
     

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