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348 Fuel pump, fuel pump relay, fuel regulator, ECU issue ?

Discussion in '348/355' started by rich scrimshaw, Oct 5, 2020.

  1. rich scrimshaw

    Oct 5, 2020
    9
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    YYC 1994 348 Spider
    Hi all,
    Looking for some help on my 348...… I have a fuel pump issue..... The fuel pump keeps filling cylinders up with fuel.... sometimes with the ignition on of ignition off (very strange)

    Any advice anyone ? all information appreciated
     
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  3. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
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    Mitchell Le
    I think we need more details on this intriguing problem.

    The fuel pump cannot be on with the car off. If it is, you have major electrical problem.
    Even when the fuel pump is on, it cannot spray fuel into the cylinders unless there is a signal that turns the injectors on, or if the injectors are stuck on and leaking.

    One suggestion: Which ever cylinder is being filled, pull that injector out of the car and check its flow rate for leaks. Or pull all of them and send them out for cleaning and testing if you are not equipped to do that.
     
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  4. Qavion

    Qavion F1 Rookie
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    Ian Riddell
    #3 Qavion, Oct 5, 2020
    Last edited: Oct 5, 2020
    Does the engine otherwise run normally?

    With the car switched off, you would hear the fuel pump/s running, so I'd say that residual pressure in the fuel rails and, as Mitchell says, one or more leaky injectors is causing the problem.

    It's hard to imagine an electrical fault which would create this issue. You would need both a power fault and an ECU signal fault and even then, it would only affect one cylinder on one bank.

    Can you identify the wet cylinders?

    Is there 12v power on any of the injectors with the ignition off?
     
  5. Qavion

    Qavion F1 Rookie
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    If the injector plugs are hard to get to, the respective bank MAFs have the same power source as the injectors (MAF plug pin 1)
     
  6. Ferrarium

    Ferrarium F1 Rookie
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  8. ernie

    ernie Two Time F1 World Champ
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    I'm with Mitch. We need more information.

    Having said that......

    IF .......... the fuel pump continues to run with the key off, it sound like you have an electrical issue. You probably will want to check the condition of the ignition switch. Either that or, if you have some sort of alarm system, you may want to remove it all together.\

    Never the less, we need more info.
     
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  9. Qavion

    Qavion F1 Rookie
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    +1

    Even a stuck ignition wouldn't explain the fuel getting past the injectors. As I recall, the ECUs need to see engine rotation before the injectors are commanded on.

    We've had a rash of some rather unusual problems on these cars in recent days. Having said that, this car would have had to have been neglected over a long time period to accumulate a sufficient number of electrical and mechanical defects to produce all of these symptoms.

    As mentioned earlier, you would hear the pumps running with the engine off, and if they were running, the battery wouldn't last too long.
     
  10. m.stojanovic

    m.stojanovic Formula 3
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    Dec 22, 2011
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    Miroljub Stojanovic
    +1

    On windy days, too much air is blown into the cylinders of my engine and it is very difficult to start (too lean mixture).
     
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  11. ernie

    ernie Two Time F1 World Champ
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    LOL
     
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