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  • [Corsa D 2006-2014] CORSA ECU printout help needed to understand it

    I have the print out of the ECU from a 63 plate corsa 1.4
    The engine gave up at 11615 miles (or km?)
    Vauxhall Eden say that it is not warrantied due to driver error because apparently my son was driving at excessive speeds and engine revs. now I don't doubt for one minute he has put his foot down at times, but at the time of the engine failure he was on a main road and says he was doing about 30 which I would calculate at probably about 40!! the person that stopped behind him stated that they were doing the same speed as the rest of the traffic,
    Vauxhall have said that the engine imploded! the AA who recovered him said that it was a cam chain failure.
    we have been given a printout from the ECU as 'proof'
    Now I don't understand all this am I being fobbed off being female? and they are trying it on or does the ECU printout really prove who was at fault?
    could someone pleas try and explain it to me
    many thanks
    Attached Files

  • #2
    The engine speed is showing at 7950 rpm which is excessive. He may have been doing 30-40 mph but which gear was he in?

    77 km/h is about 48 mph - which is what the ECU is showing as the recorded road speed at the time of the engine overspeed. Regrettably that suggests he was using a lower gear and maximum throttle. At that kind of rpm the loads on parts like the timing chain can cause it to slip, sudden lifting off the throttle puts an enormous reverse load into the engine which is usually when chains let go.

    Edit - just to clarify, under normal driving the engine turns between 2000 to 5000 rpm. Even then many drivers don't go above 4000 rpm in normal driving situations. The point of failure is nearly twice that. The AA man could well be right that the cam chain has gone, but from the data it looks like if went due to the way it was being driven.
    1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

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    • #3
      Does that not suggest the damage was done by going to the wrong gear? Perhaps 3rd to 2nd instead of 4th?
      The rev limiter is below 7950 surely?

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      • #4
        Good point - 48mph in 2nd if it was a missed upshift would take it past the limiter.
        1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

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        • #5
          Thank you for the replies. But still none the wiser as I don't understand how this proves his driving was to blame?
          It says acceleration 0%
          His explanation was driving when the engine started juddering and making a strange sound. So he depressed clutch and tried to bump it
          My point is does this actually prove he was driving like a teenager and actually caused the damage or did the damage occur before and is that reading when in his inexperience of driving and panic kick in and he chose a wrong gear to try and get it started again?
          Sorry just trying to get to the bottom of this as apparently this is proof? But I don't really understand it all.
          The guy following him that stopped to help said he was driving normally but obviously he wouldn't know what gear my son was in
          Thanks again

          Comment


          • #6
            OK - that additional information is useful. The data says that the car was travelling at 77km/h when the ECU logged the engine overspeed, it also says it was in 2nd gear.

            77km/h is 48mph, far too fast to engage 2nd gear to attempt a rolling bump start.

            When you bump start a car you need to press the accelerator pedal, it shows the accelerator at 0% - which may be due to an inexperienced driver not knowing how to bump start a car. Usually to bump start a car you use 2nd or 3rd gear, but that is with a couple of blokes pushing it along at about 5mph. You do not engage 2nd to bump start it at 48mph.

            That would explain why the engine has revved beyond the limiter - to 7950rpm.

            When an engine suddenly gets pushed to those revs by dumping the clutch in low gear at a higher speed it means the car is forcing the engine to turn in a way it is not meant to. It's what is called 'reverse loading' - nothing to do with reverse gear, it simply means the car is forcing the engine to turn so the forces are back to front.

            Sudden application of high levels of such force can cause timing chains to jump the teeth on the camshaft sprockets, the camshafts are then out of time with the lower end of the engine, which causes the valves to hit the pistons. This always causes damage on these engines, if it happens at high rpm the damage is catastrophic.

            From the evidence - even if there was a problem with the engine so it cut out, the data suggests that the driver has then made an error in engaging too low a gear for the road speed and forced the engine to over-rev. What may have been a minor problem then becomes total engine failure. At 48mph you'd engage 4th to try a rolling bump start and you'd apply some throttle. With no throttle the engine doesn't stand a chance.

            Whichever way you look at it, with regret and much sadness, it does look like driver error caused the damage the engine has sustained.
            1972 Viva restoration thread - http://www.thecorsa.co.uk/projects-b....html#post1534

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            • #7
              Hi
              Sorry to say ,but I agree. The car has revved to 7950 revs in 2nd, at 48mph, and thats well beyond normal.He may have tried to do a jump start at far too fast a speed for 2nd ,but even if there had been a prior fault it will now be impossible to prove as he has comprehensively wrecked the engine by driver error. Alternatively he may have dropped from 5th into what he thought was 4th because the car was not pulling smoothly , but accidentally went into 2nd.He may then have let the clutch in hoping to 'jump start 'and correct the situation on the move , but the damage was already done. This is still driver error and I doubt they will pay up on either scenario. If its any consolation neither means he was driving like a lunatic 'teenager'. It could happen to any inexperienced driver, especially if the car is unfamiliar.
              Last edited by Bugman; 06-05-2015, 02:47 PM.

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