Car suddenly stops running, runs again after 10 minutes. | FerrariChat

Car suddenly stops running, runs again after 10 minutes.

Discussion in '308/328' started by gjv, Sep 17, 2019.

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  1. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    I have had my 308 QV for 7 years and suddenly encountered a problem I can't figure out.
    While driving last night, with normal operating conditions and a cool ambient temperature of 64F, the car suddenly and without any warning 'died'. It literally felt as if someone had turned the engine off with the key, but all electrics were working normal (lights, blinkers, etc.). I tried to start the car several times (the engine cranked), but it simply would not fire back up. After about 10 minutes on the side of the road, I tried again and the car fired right up. It ran completely fine for about 5 miles and then it happend again. Same thing. I waited again on the side of the road for about 10 minutes and managed to start it again and drive it home.

    What could cause this?

    It can only be air, fuel or ignition, right? Air is for sure not the issue.

    Fuel: I first thought that it could be some form of vapor lock, but that wouldn't explain its sudden nature after 7 years of driving this car without any issues. Also, when attempting to start the engine (without success) immediately after the problem occurs, I can hear the fuel combust/rumble in the exhaust system, which makes me think that the fuel supply is fine and just passes the mixture on into the exhaust manifold when trying to start it. That would also eliminate a clogged fuel filter. The car runs fine again after ten minutes or so. The only thing I noticed when it happened the second time, was that it happened right after I pushed the throttle deeper than before. This could also just be a coincidence, because the cable only moves the throttle plate and should not shut off the engine.

    Ignition: If it was the ignition, then what would cause the intermittent nature and why would it fix itself after ten minutes? It does not make sense. Could it be a failing relay? If so, why would the problem be intermittent?

    Needless to say that I have been thinking about this all night. My car fired right up this morning and runs smoothly. This is highly frustrating because I don't know how to diagnose a car which runs fine,, even though it can suddenly cut out at any given moment.

    Hopefully someone on this forum has experienced the same issue and can help me figure this out. Thank you guys in advance.
     
  2. ClydeM

    ClydeM F1 World Champ
    Owner Rossa Subscribed

    Nov 4, 2003
    10,462
    Wayne, NJ
    Full Name:
    Clyde E. McMurdy
    Have the original fuse blocks? Check the fuel pump fuse. It's probably brown showing signs of high current draw and contact may be poor. Next instance of this, you can temporarily jumper it with tin foil & see if it starts.
    Check the fuel pump. My intermittent fuel pump manifested itself as the hot-start problem
     
    19633500GT likes this.
  3. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    I have the birdman fuse blocks and the fuse is ok. I have the hot start problem for a fee years, but it always fires on the third try when hot. I did not connect this issue to the 'sudden cut out' I experienced yesterday. I will check the fuel pump, but how can i tell if there is an issue? The car and pump run fine right now. Could it be the relay?
     
  4. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Owner Rossa Subscribed

    May 4, 2001
    35,282
    Birmingham, AL
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    Tommy
    This happened to me 2 years ago.

    It was a bad connection in the fuse panel to the fuel pump circuit.

    Look VERY closely here first. All I needed was to tighten the connection on the spade connector.
     
  5. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    Thank you for pointing me in the direction. I checked the connections in the fuse panel and cleaned the spade connector, just in case. I removed the fuel pump relay and i can hear something rattle inside when I shake it. I will replace it and see if the problem reoccurs.
     
  6. Dr Tommy Cosgrove

    Dr Tommy Cosgrove Three Time F1 World Champ
    Owner Rossa Subscribed

    May 4, 2001
    35,282
    Birmingham, AL
    Full Name:
    Tommy
    My car would just shut off driving down the road. I could restart it while I was still on the move. It got worse and worse.

    Strange because it was either running absolutely perfectly - or it was just off. No stumbling or backfiring, nothing. Just off. And then it would start right back up and run tip top as if nothing had happened . I flatbedded it to my guy in Atlanta and he called me the next day. All he had to do was crimp the spade connector. It was loose and moving around.

    Sounds like our symptoms are exactly the same.
     
    Dane and gjv like this.
  7. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,322
    Tallahassee, FL
    Mine was shutting off completely as if I had pulled the key out, at random times. Sometimes going down the highway, sometimes driving down the city streets. You could never predict when it was going to happen.

    It ended up being a bad ground wire.
     
    Dane and gjv like this.
  8. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    I will check all the grounds, just in case. I have already crimped the spade connector and ordered a new relay just in case. Thank you for your suggestions.
     
  9. Mule

    Mule F1 Rookie
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    Jun 25, 2003
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    dave80gtsi likes this.
  10. dave80gtsi

    dave80gtsi Formula 3
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    Nov 3, 2003
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    Sounds like perhaps some iffy contacts within the ignition switch?

    While running, try wiggling the key about and see if there is any mischief.
     
  11. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,322
    Tallahassee, FL
    For what it's worth, mine did this almost exclusively after 20 or more minutes of driving. It ran perfectly fine when it was cold.

    I finally realized that something in the car was wrongly heating up, which led me to start checking every associated electrical connection I could find.
     
  12. BLACK HORSE

    BLACK HORSE Formula 3
    Silver Subscribed

    Feb 11, 2004
    1,937
    California - Bay Area
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    Rob
    I bet its your ECU unit(s)... one or both of them is probably going out. You can pull them out to have them tested.
     
  13. Mark Young

    Mark Young Rookie

    Sep 5, 2018
    17
    lawrencetown NSCanada
    Full Name:
    Mark Young
    I just want to thanks guys. My 82 just started to screw up as you described.
    I had sit on the side of the road for 15 minutes than it would start as if nothing was wrong.
    I found that the fuse was loose.

    Fingers crossed that it was the fix. So far so good
    Mark
     
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  14. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    Well, here we go again. I thought I had fixed the issue by checking the connectors (including the ones under the passenger floor) and by replacing some of the relays. Car ran fine today for about 30 minutes and.... suddenly died. I would not start up until 3 minutes later. It ran totally fine for about 15 seconds and .... same thing. It died just as I tried to drive on again. All other electrical functions are fine. Waited 15 minutes and it ran for 3 miles. Totally normal.. again suddenly died completely. It is only the engine and nothing else.

    A few things I noticed:
    - It seems to be occur when I shift gears or right after I get off the throttle. Could be a coincidence.
    - I also notice a hissing sound when I remove the fuel cap. Hard to tell if it is an over pressure or a vacuum. What I do know is that air either streams in or fuel vapor streams out of the tank. Is it normal for a 308 to develop pressure in the tank? I have driven my car for 8 years and noticed it before when I would refuel. Never thought anything of it and clearly the car ran fine for 8 years.
    - Could this be caused by a bad fuel filter? I would think that a bad fuel filter would not cause an "instant shut off" after 30 minute of normal driving without any other issues.
    - Could it be the fuel pump going bad? But again, why would the fuel pump suddenly quit and only after about half an hour of driving?

    This is driving me crazy. I guess the question is: What makes a 308 engine suddenly die after about half an hour of totally normal operation without any signs of trouble at all. Purring smoothly like a kitten and then..... nothing

    Thank you guys in advance for any pointers.
     
  15. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
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    Brian Crall
    #15 Rifledriver, Apr 7, 2020
    Last edited: Apr 7, 2020
    Wouldn't kill the whole motor. They do not quit in unison.
     
  16. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
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    Brian Crall
    Very common set of symptoms for 2 things. When those fuel pumps go bad they get intermittent. Also the TDC and RPM sensors do that. When the temperature changes the winding circuit opens and closes randomly. You have a TDC sensor for both sides so it isn't those but it could be the RPM sensor since it feeds both banks. The only way to test is to remove it, connect it to an ohm meter and lightly bang it on a hard surface. If the continuity comes and goes it is bad.
     
  17. JohnnyS

    JohnnyS F1 World Champ
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    Oct 19, 2006
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    Check the electrical connections on the fuel pump. Look for grit/dirty connections. Do you have a lift? If so see if wiggling the fuel pump wires while running causes the engine to stop. Could be a kink that has caused a wire to be broken. When the engine is cold, the connection is made but when hot, things expand and the connection may expand enough to break the continuity. Just some thoughts.
     
  18. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    I guess I'll start with the fuel pump connections (I have checked all connections inside the driver's compartment, but have not yet gone under the car to the fuel pump itself. Unfortunately I no longer have a lift. I used to have one, which was very helpful when I replaced the clutch. We moved to another state and our new home has no room for a lift. Anyway, I start there and will also remove and test the RPM sensor. Sounds like a perfect "lock down" project. While I'm under there, I might as well change the fuel filter too.
     
  19. ClydeM

    ClydeM F1 World Champ
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    Nov 4, 2003
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    IMHO: order 3 replacement sensors & replace them while your in there. Yours are old. I dont know how to check the fuel pump, but per Rifledriver - I suffered from the intermittent and it took several mechanics & shops to pinpoint the problem.
     
  20. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
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    Brian Crall
    My hearing used to be good enough I could hear them. That was a long time ago.
     
  21. gjv

    gjv Karting

    Feb 20, 2012
    173
    Georgia
    Thank you for the advice! I will probably do that even if they are fine. It won't hurt to replace them.
     
  22. mike996

    mike996 F1 Veteran

    Jun 14, 2008
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    Mike 996
    Before you do any work, try a drive with the fuel filler cap removed and see if there is any change in the symptoms...
     
  23. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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  24. Irishman

    Irishman F1 Rookie

    Oct 13, 2005
    3,518
    Raleigh
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    Should have just 'liked' but what a great post : - ).
     
  25. johnk...

    johnk... F1 World Champ
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    Normal with a partially filled tank. part of the evap system.
     

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