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Thread: Error code 34 not fixed by new coil

  1. #1
    apriliaforum Junkie bigaprilia's Avatar
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    Error code 34 not fixed by new coil

    Hi folks,

    From time to time I've had the EFI light flash on start-up and sometimes while riding. I hooked up the diagnostics and used TuneECU which indicated the centre plug coil on the rear cylinder was fault. I also checked the voltage with TuneECU running in the centre plug on the rear cylinder, and it was dropping in and out. I replaced the old coil with a new part and I'm still getting the error 34, which leads me to suspect a wiring problem somewhere. I've not chased down wiring issues (other than the brown connector) on this bike before so some input would be great. The leads for the rear coils appear to run back between the cylinders in the main harness but I can see what they feed into. Does anyone have any pictures or suggestions of things to check ie connectors and shorts I can test with the multimeter?

    Thanks,

    Al
    2003 Futura with Quill EVOII end cans, H-pipe, Power Commander III 108bhp @wheel
    2001 RSVR with Aprilia shotgun II exhaust, Aprilia race chip, Power Commander III 128bhp @wheel
    1985 GSXR1100 with 1109 weisco oversized pistons and liners, dyna coils, k-tech race CDI, Stage III dynojet, Ohlins rear shock, GSXR1100 WT front forks, GSXR1100 M front and rear wheels, 134bhp @wheel
    http://barnfindmotorcycle.com

  2. #2
    apriliaforum expert RAS's Avatar
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    Think I'd open the jacket loop behind the right side radiator from the bottom of the loop as far up toward the motor you can reach.

  3. #3
    apriliaforum expert deefred's Avatar
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    Are you sure you replaced the correct coil?

    You can disconnect the low tension connector on the suspected coil and check that the corresponding error code matches with that coil.
    2001 RST Futura in stream Silver.
    Mods: Modified Öhlins fork from mille R, EBC 320mm brake discs, HEL front brakelines, Carbon RS 250 front fender, Wiring mod for charging. Engine related:05 map, Iridium plugs, tuneboy, derestriced intake, old mille airboot, staintunes exhaust. Lambda bung hardbrazed in the "breadbox". Öhlins mille R rear shock with 110N/mm spring and the integrated hydraulic preload adjuster. LED Voltmeter installed inside the dash for monitoring charging. Duc 999 radial m/c for brake and clutch.
    NWS hugger. Equipment: Famsa tankbag,
    CBR 600 -07 MOSFET R&R FH008EE providing stable 14.4 - 14.5 V (with my wiring mod). Daytona heated grips with mccoi pwm controller and automatic chain oiler

  4. #4
    apriliaforum expert spesnaz's Avatar
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    that's a good call as the high tension wires may have been swapped at some time over the years. Check the color of the wires at the coil to be sure you have the correct one.

    It's critical that you check the high tension wires as well, they are resistor wires, and do break down...especially the rear ones. Be sure that both ha ve the same resistance. If you have a high voltage failure, it rapidly kills the coil.

    Bob

  5. #5
    apriliaforum Junkie bigaprilia's Avatar
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    Thanks folks.

    Correct coil lead diagnosed, I did the usual swap coils to double check. I also tried several new coils because I purchased a set of four, and each one gave the same result. After looking at the wiring diagram, the low tension leads trace back to the ECU front and rear connectors so will I try a continuity test there first.

    Al
    2003 Futura with Quill EVOII end cans, H-pipe, Power Commander III 108bhp @wheel
    2001 RSVR with Aprilia shotgun II exhaust, Aprilia race chip, Power Commander III 128bhp @wheel
    1985 GSXR1100 with 1109 weisco oversized pistons and liners, dyna coils, k-tech race CDI, Stage III dynojet, Ohlins rear shock, GSXR1100 WT front forks, GSXR1100 M front and rear wheels, 134bhp @wheel
    http://barnfindmotorcycle.com

  6. #6
    apriliaforum expert spesnaz's Avatar
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    Glad you have TuneECU to help pinpoint the troublesome coil.

    Those four voltages shown are a dynamic test showing the load of the coil and secondary, not just the primary circuit. As the ignition coils are essentially high voltage transformers, remember that if you have an arc, or a load from a carbonized electrode, or an improper gap, you will see fluctuations.

    As the secondary load changes, your coil primary is linked magnetically to it. There actually was an engine management scheme tested that could monitor combustion without oxygen sensors, by this effect.

    Take the secondary lead and give it a close inspection for any signs of damage, and give it a wiggle, to see if the casing has hardened over time. The two paired ignition leads, the fronts or rears, will have the same resistance. hey are resistor wires and as such, they do break down. Changing the coil effectively changes only part of the high voltage circuit. I had a damaged boot on one of my rears; it occasionally arced, and broke down the wire. Next in line was a dead rear coil as the spark voltage rose above the coil's internal insulating capacity, cooking the coil. If I had not been curious and measured the coil wire resistance, I would have been replacing a lot of coils.

    The primary circuit is easy, as all four have the same power source, and there are four "grounding" switched leads running to the ECU. You can disconnect the ECU and with a good multimeter, read the resistance of the four driver wires. If it's only one coil with erratic readings in TuneECU, the suspect connection would be between the coil connector and the respective pin at the ECU. It should be under 0.3 ohms.

    The Fluke has a cool high resolution mode for low resistances as well as a zeroing function to calibrate it for the resistance of the test leads. If you are using a more basic meter, no worries. Touch the test leads together and measure the lead resistance, then add this to the wire in test. For example, if the test lead reads 0.7 ohms, and the wire reads 1.1 ohms, subtract the 0.7 from your result, yielding a measurement of 0.4.

    The HT wires on mine were something around 1-2k ohms, I test so many things it's hard to recall. Damn spare wires are laying around someplace here...

    The rear wires turn into crunchy critters compared against the front, because air flow is very different on the Rotax for each wire pair. My fronts are original and are as soft as a baby's butt, while the rears were crispy bacon.

    Bob

  7. #7
    apriliaforum Junkie bigaprilia's Avatar
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    Thanks for the info Bob.

    I haven't tested the low tension wires yet for resistance, but don't look damaged or stiff. I'll unplug the connector blocks at the ECU this weekend and test the resistance to the coil connection which is giving me the issues. The biggest pain will be unravelling the wiring loom to chase relevant section of wire to replace. What is the wiring route for the rear coil wires? Do they run back over the engine between the two cylinders, then around the front of the engine before back to the ECU? I have the middle side panels off at the moment but was wondering if the panels around the front of the tank need to come off to access the main harness.

    Cheers,

    Al
    2003 Futura with Quill EVOII end cans, H-pipe, Power Commander III 108bhp @wheel
    2001 RSVR with Aprilia shotgun II exhaust, Aprilia race chip, Power Commander III 128bhp @wheel
    1985 GSXR1100 with 1109 weisco oversized pistons and liners, dyna coils, k-tech race CDI, Stage III dynojet, Ohlins rear shock, GSXR1100 WT front forks, GSXR1100 M front and rear wheels, 134bhp @wheel
    http://barnfindmotorcycle.com

  8. #8
    apriliaforum expert Motech's Avatar
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    Resistance testing of coil trigger leads is futile and can spin you in circles. Twelve broken with two good strands in the circuit can give you a "good" continuity test result, but load that circuit with current and it will fail every time and spin you in circles. Volt-drop testing is the easiest way to test if a scope and the training to use it are not an option.

    This backass setup uses such loose enabling criteria for coil error codes that a worn spark plug can trigger one. In the time you've spent fighting this thing, a set of CBR coils, primary connectors and new secondary cables could have been installed for less than the cost of one "aprillia" coil. Then, if no more codes, all problems solved forever.
    No Matter Where You Are, There You Go!

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