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3.2 Can't Hold idle sounds like a cylinder missing

Discussion in 'Mondial' started by moysiuan, Apr 12, 2020.

  1. moysiuan

    moysiuan Formula 3
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    Nov 1, 2005
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    3.2 Mondial:

    Driving on highway, accelerating hard onto on ramp, something briefly "missed" like a cylinder was not firing but car kept running on the highway, when came to off ramp, car would not hiold idle and stalled, and would not start (cranked, but no sign of ignition at all (flooded?). Towed home.

    Back home, the car started, but barely holding an idle, gas smell so running rich or a cylinder not firing. Stalls, then car won't start at all. An hour later will start but idles very badly and stalls, gas fumes, etc. Feels like at least one cylinder is not firing.

    I have replaced distributors, rotors, plugs, coils in the last two years. Checked fuse box connections, swapped fuel pump relay for another of the same type. Engine is getting spark, at least at the couple of wires on the reasr bank easily checked. My hunch was I had a suspect plug wire on the front bank (the connector to the extender seemed loose from when I replaced it a while ago), so I took off the front bank distributor, replaced the wire with an old spare, checked for continuity at the cap for all wires, all seems in order. Still a problem.

    Here may be a clue. If I take out the fuel pump fuse the car will start and idle well, but then of course stall quickly as it runs out fuel. I put the fuse in, and it would start but rough, gas fumes again. Took fuse out, started (it ran well) and promptly put the fuse back in before it ran out of fuel, and it immediately ran poorly, stalled.

    Any thoughts on what is going on here? I have been presuming electrical connection of some sort is the problem, but this fuel pump fuse experiment has me confused.
     
  2. yelcab

    yelcab F1 Veteran
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    Nov 29, 2001
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    My 328 died on me a few years ago at work. The problem turned out to be a flaky fuel pump. The fuel pump was too old, drew too much current, caused heat build up at the fuse board, and resulted in low voltage at the pump, which caused the pump to stop working. The solution for me at the time was two things:

    1. Replaced the fuel pump
    2. Cleaned up the fuse board, recrimped the connector at the fuse board that goes to the pump. It was obvious from the burnt mark.

    Having said all that, I have worked on many 308's that have flaky ignition system and the universal solution for all of those is to build a set of wires that eliminate the spark plug extenders. There are other ignition problems with the 328 such as frequency valve, rpm sensor, fuel distributor, WUR, and ignition coil electronic modules. By far, the biggest failure has been spark plug extenders, which led to the design eliminating them (Credit Joe Chung).

    Everyone for whom I performed this change (including myself) have been extremely happy that the stupid extenders are designed out forever.

    Good luck to you.
     
  3. M. Brandon Motorcars

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    On a Mondial, the fusebox major weak point is the fuel pump relay circuit. Most likely this has melted inside your fusebox or has burned up enough to increase resistance enough so that the fuel pump isn't getting enough voltage.

    Search on how to bypass the fusebox for the fuel pump relay circuit, or replace the fusebox.
     
  4. spicedriver

    spicedriver Formula 3

    Feb 1, 2011
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    Get an ohm meter and measure the exact resistance of the wires.

    From cold engine (overnight) run the car for 2 minutes. Then touch each one of the test pipes near the heads. They should be too hot to hold your finger on. If not, that cylinder is not firing. I would think it's an ignition problem because of the unburned fuel smell.

    Sometimes there is spark, but not a strong enough spark.

    A clogged WUR filter will cause rough running from a lean condition. The filter is under the larger of the 2 pipes. Using Techron regularly will prevent this.
     
  5. Eddie.h

    Eddie.h Rookie
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    Mar 30, 2015
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    Very interesting. My 83 QV has a similar issue. Will run fine and then will stall at idle unless the rpms are kept up. Rolling up to a stop or parking space the engine tries to die. We have rebuilt the fuel distribution system new injectors. New fuel filter. New vacuum hoses. Ran fine for a few days and now it is back at it. It acts like it is not getting enough fuel. I am wondering if it could be gunk in the tank clogging up the filter. Will check the ignition as you recommend. Thanks.


    Sent from my iPhone using FerrariChat
     
  6. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Yes, you're a Witch ;) Seriously, what version 3.2 Mondial, and can you be more specific about which fuse you are messing with (i.e., fuse name, or number, as shown in your OM).
     
  7. spicedriver

    spicedriver Formula 3

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    #7 spicedriver, Apr 12, 2020
    Last edited: Apr 12, 2020
    Add a bottle of Techron with every tank of gas, and you won't have to worry about gunk. Also, sounds like your mixture screw needs to be adjusted.
     
  8. moysiuan

    moysiuan Formula 3
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    1988 Mondial 3.2, Swiss Model (KE-3 Injection, i.e no WUR). Took out the plugs, they were all fouled, so replaced.

    Car started and ran perfectly. Took for a few blocks test drive, then the same problem recurring, barely able to idle, fuel smell. Mangaged to limp back home and avoid another tow. Maybe the problem correlates with the car heating up? But in this instance I drove about 8 blocks before the troubles started again.

    The fuse box is original. I have renewed the typical "burnt" connector some years ago, and it shows no sign of overheating presently. I do have a new OEM fusebox, and could swap that out if required. Image Unavailable, Please Login

    Re: my experiment with the fuse, it is the fourth in from the right side, a 15 amp labeled "Fuel Pump" on the plastic cover graphics.
     
  9. spicedriver

    spicedriver Formula 3

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    Spark plugs fouled how ? Wet fuel, carbon, oil ?

    Also, when is the last time you replaced the spark plug wires ?
     
  10. spicedriver

    spicedriver Formula 3

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    Could be that your fuel injection system is overly rich from some faulty component. By disabling the fuel pump, pressures in the injection system change, and bring the mixture into spec.
     
  11. M. Brandon Motorcars

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    #11 M. Brandon Motorcars, Apr 12, 2020
    Last edited: Apr 12, 2020
    Here's something else to try. In fact, I should have suggested this first; not sure why it took me so long to think of it, given your symptoms. I just had this happen on a Mondial recently.

    In your trunk, down on the right side below a cover, is the Jetronic ECU. Next to the ECU, there's a big relay with a fuse on the top, which is the frequency valve protection relay. When that relay fails, it often causes symptoms such as you are describing. Fuel smell, can't hold idle, feels like a cylinder bank is down, no power.

    Change that relay out for a good one, and I bet your problem goes away.

    EDIT: described the relay properly
     
  12. Steve Magnusson

    Steve Magnusson F1 World Champ
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    #12 Steve Magnusson, Apr 12, 2020
    Last edited: Apr 12, 2020
    Can you access the connector of the antievaporartive valve, item 32, shown here?:

    https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/mondial-group/mondial-3-2/antievaporative-emission-control-system-for-us-version.html

    Making a voltage measurement from the red wire terminal in the unplugged harness connector to ground would be able to tell a lot about your KE3-Jet system operation -- it should be +12V whenever the engine is running, even if running poorly. This will let you know (before buying) if you need a new protection relay with the fuse as Michael suggested (i.e., if +12V when the engine runs well, but 0V when the engine runs poorly = justifies buying a new protection relay).
    If it easier to directly access the protection relay, you can make the same measurement there -- when the protection relay is plugged in and the engine is running (even if badly), the voltage between terminal 31 and terminal 87 should be +12V. If 0V with the engine running = justifies buying a new protection relay.
     
  13. moysiuan

    moysiuan Formula 3
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    That's the protection relay I think you are referring to. Replaced that years ago, still have the original one as a spare so could swa p and see if that helps. Would that cause an intermittant problem?
     
  14. moysiuan

    moysiuan Formula 3
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    Wet fuel, carbonized. maybe a bit of oil.

    Plug wires changed a year ago (and caps, rotors). Checked the difficult to access bank to double check all the wires had the correct continuity/resistance.
     
  15. M. Brandon Motorcars

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    Right, the frequency valve relay, with a 10A fuse on it for protection. And, yes, I've seen it cause intermittent problems.

    I would think, when the car is running poorly, that the frequency valve wouldn't be buzzing, if the relay really is the problem. You can check that as well.
     
  16. spicedriver

    spicedriver Formula 3

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    Does the KE3 have a frequency valve ?
     
  17. M. Brandon Motorcars

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    Yes.
     
  18. spicedriver

    spicedriver Formula 3

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    I thought the KE3 had an electromagnetic actuator attached directly to the body of the mixture control unit. And this handled all the mixture changes. But I could be wrong.

    Anyway, I would check the pressures. System pressure should be 6.1 - 6.5 bar.
     
  19. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Correct - no frequency valve on a KE3-Jet or KE-Jet (so no easy check to just feel if it is vibrating as a way to confirm/deny the protection relay operation like on a K-Jet with Lambda system) The EHA also provides the same functions that the WUR provides on the K-Jet systems.
     
  20. moysiuan

    moysiuan Formula 3
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    Yes, there is no frequency valve on my Ke3 system.
     
  21. M. Brandon Motorcars

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    Fair enough boys, I was incorrect, and you are all correct. I have had Mondial QVs and Mondial 3.2s, and I was getting them confused.

    Honestly, I've learned most of my knowledge from the commenters in this thread over the years, and then applying it to my cars. I should have known better than to stick my neck out there with the experts. :)
     
  22. spicedriver

    spicedriver Formula 3

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    The test I've used before to isolate ignition vs. injection faults with the Mondial is to pull the fuel pump fuse. Remove the air box, push down the air vane and spray starting fluid into the FD. The motor should start right away, and have a smooth idle. Really smooth idle. And it will keep idling if you continue to spray more fluid inside. This completely bypasses the injection system. If you can't get a smooth idle this way, the fault is likely in the ignition system.

    Plugs have to be clean and dry. I prefer using a propane torch to clean the plugs.
     
  23. mike32

    mike32 F1 Rookie

    May 13, 2016
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    Are you getting any back firing or missing of sparking, any fuel to smell on the dip stick
     
  24. moysiuan

    moysiuan Formula 3
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    No backfiring. Will check dip stick in the morning.
     
  25. moysiuan

    moysiuan Formula 3
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    The KE3 injection is unique to the late Swiss market Mondial, and I understand functions more like that of the Testarossa system.
     

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