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I had a steady Lane A light come on, it could be reset but returns after a short time. Downloaded BUDS, it was showing Injector Failure on Lane A. I had seen this before, it is nothing to do with the Injectors, it turned out to be an Open Circuit Resistor in the Spark Plugs Connectors. This can be measured using a multimeter on ohms, measuring between Plug Caps on the same Coil Pack (1T & 1B etc). Normally it should measure ~18k ohms (two 4.7k ohm for the spark plug caps and 8.2k ohms for the coil pack). The spark plug cap connectors can be removed an measured separately to eliminate the faulty unit.

I dissected some of the faulty Spark plug connector and found visual evidence of the failed resistors (see photo).

Has anyone seen this and does anyone have any idea of what causes this failure ?

Thanks

Malc

9808_1_20230502_171855.jpeg (You do not have access to download this file.)
  • Re: Lane A Light Steady - Injector Error

    by » one year ago


    First of all, excellent find!  I have not seen this before, even with plugs boots that were heat damaged. I remember reading that a failed spark plug resistor may still allow current to pass when high voltage from the coil is applied, even though it may test as open with an ohm meter (which is at a very low voltage). The plug may still fire, but this also creates electrical noise as the arc jumps the gap in the faulty resistor.  I’m guessing, but maybe this is why the fault was interpreted by the ECU as an injector failure.  Was there external heat damage on the plug boot?


  • Re: Lane A Light Steady - Injector Error

    by » one year ago


    Jeff B, I agree with you that the plugs were are still producing a spark its just the ECU detects it as a fault, although it thinks it is a fault with the Fuel Injectors. A ‘Lane A’ Steady Light comes on.

    I couldn’t see any external heat damage to the plug connector, but I think the heat is being conducted up through the Spark Plug directly into the internals of the connector.

    I will change them and see how I get on.


  • Re: Lane A Light Steady - Injector Error

    by » one year ago


    Hello people, I spend exactly the same, the caps have problems in their internal resistance which is 5komhz.


  • Re: Lane A Light Steady - Injector Error

    by » one year ago


    Malcolm,

    You may be right about heat being conducted from the plug up to the resistor in the boot, and that illustrates one reason why it’s important to use the heat transfer paste on the plug threads. The heat transfer paste helps to move heat from the plug to the head, where it’s carried away by the cooling system.   Also, typically the lower plug boots run hotter because of their proximity to the exhaust.  Anyway, I’m going to keep this in my notes: fuel injectors fault code = test plug boot resistance first.  

    Your post makes me think about the fact that I have a $250 code reader for cars that you plug into the diagnostic port to read the faults.  This tool then connects by to a database and gives you a definition of the code and the top 5 fixes reported by mechanics.  On the other hand I have  $1,000.00 Rotax BUDS dongle that has essentially no information about diagnosing the codes. Assuming help with these codes won’t be provided by Rotax, maybe we can get this website to start a database where people can report the solutions they have found for codes, and also which codes routinely happen during normal engine operation.  Over time, this could become a valuable tool for owners of injected Rotax engines.  


  • Re: Lane A Light Steady - Injector Error

    by » one year ago


    Hi all,

    can someone explain to me why ECU didn't report this event as Ignition Coil failure, instead of Injector failure?

    Thanks and Regards

    Dejan


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