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2005 corsa c 1.2 twinport tick over is uneven

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  • [Corsa C] 2005 corsa c 1.2 twinport tick over is uneven

    Have just got this car from someone who have had enough, it snapped the cams so they had it repaired but the tick over is uneven and hunting diagnostic report running rich have check for leaks no joy, but have heard I need to get the electronic throttle reset, any help much appreciated car to good to scrap.

  • #2
    Welcome to the Forum.

    As the engine has had work done on it in recent times, I would recommend that you invest in a FULL service. This will ensure that the oil is not contaminated and liable to cause further problems, it should also include new oil and air filter elements (a blocked air filter can produce the 'running rich' condition that you speak about.) New spark plugs could also help (part of a full service) If you don't know the service history, a new fuel filter might also be a good investment.

    You could also try buying a can of 'Carb Cleaner' and clean out the throttle body - There will probably be a lot of smoke from the exhaust when you do that, but it should quickly clear.

    If you have a check for fault codes, try and obtain the code numbers and we might be able to give you a more accurate diagnosis.

    Depending upon how good the work was when the cam shaft(s) were replaced, it may just pay to have a compression check made to eliminate any possibility of a valve that isn't seating, or even piston damage.

    As you say, if the rest of the car is in good order, it is too good to scrap, and if you didn't pay too much for it, investing a little in sorting its problems, should give you a reliable car.

    There have been problems with these engines due to fitting poor quality oil filter elements, parts of which have been known to break off and block oilways - That COULD have been the cause of the camshaft failure. - I would recommend genuine Vauxhall oil filter elements.

    Regards

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    • #3
      Hi thank you for reply, the compressions are all good, they had new coil pack, plugs, air filter, it has full service history 63742 miles, if you hold it at 1500 rpm it runs fine and drove fine, the throttle body clicks but I took this off and cleaned but it stills clicks, I pulled the hose off the fuel tank vent valve and that had no effect.
      Regards

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      • #4
        Have done a pedel check and no codes come up, we changed the electronic throttle body because it was clicking but the replacement is also ticking and the person we got it from said it came off a runner that had been in a accident, could this be the problem the ecu is not working with the throttle body.
        Regards

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        • #5
          The throttle body is supposed to click when you turn the ignition on and off and even when running will click . To reset the throttle body disconnect the battery for about 20mins then reconnect and start the car without touching the throttle pedal and let it tick over for about 2 mins that should reset the throttle body. Don't forget the radio code if you're going to disconnect the battery.
          I'm guessing it was the exhaust cam that snapped as that's the one that usually go's. How did you check the compressions. I ask this as some people think it's just a case of changing the cam shaft and that's it . It starts up ,but will be running rough on idle . As it has bent the valves on number 4 cylinder. Even if they have taken the head off did the person lapped the new valves in .

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          • #6
            Hi, thank you for coming back, compression test was done using compression tester no 1&4 where about 20psi lower than 2&3, not sure if it was just exhaust cam that snapped but the garage replaced both, the idle is about 600rpm if you blip the throttle the responses is good. Have had the battery off all day, Had a diagnostic done and every thing was ok apart from running rich, the people I purchased the car from paid cash for the work and did not ask for any paper work but they said the head was checked ? not sure which way to go next.

            Regards

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            • #7
              You could have a air leak somewhere on the inlet manifold. Try spraying a bit of brake cleaner around the seals and joints and see if the revs pick up.
              But I still think it's something to do with the valves.

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              • #8
                Many thanks, will check the inlet manifold, but I also have a feeling it could be the valves as I think the garage just replaced the cams
                Regards

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                • #9
                  HI back again, just noticed car been left for a couple of days when I started it the tick over was 1000rpm and even, but after about 5-10 seconds it dropped back to about 750rpm and lumpy left it for about a hour and the same thing happened. have done a cylinder leak test and that was fine, could it be a fuel filter problem not shore when it was changed.

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                  • #10
                    The fuel filter is underneath just in front of the rear wheel driverside . Be careful of the plastic pipes and clips as they tend to snap off .

                    Comment


                    • #11
                      Its quite normal in cold weather for the ecu to raise the tickover for a sort time before it dropping it back to normal.(After an hour its cold again. ) Actually if its very cold I would have thought dropping back to 750 rpm after only 5 -10 seconds is a bit soon. On start up at +4c my 1.3 cdti may initially tick over at 1100 rpm then takes about 30 seconds to drop to 900, and a bit longer still to be at normal tickover. And thats a diesel which dont have the same rich and lean fuel variations as a petrol.

                      Just a though. if the car runs smooth at 1000 rpm on tickover, or if you raise the revs to 1000 on the throttle , but is lumpy on tickover at the 600 rpm you mentioned earlier, or 750 rpm maybe the ecu is metering a lean fuel/ air ratio for a hot engine too soon while the engine , or ambient air temperature is still too cold for it. (or possibly the opposite ,too rich for the actual temperature) Maybe the temperature sensor is faulty and telling the ecu porkie pies. But I am no expert,I'm not even sure if there is more than one sensor.

                      Another example of my ignorance. I believe it may be possible to access a hidden menu on the dashboard display that includes a temperature reading.(not just the cabin temperature display) This will presumably be the temperature the ecu 'thinks' is correct when metering fuel mixtures etc. But it might be wrong. If the figure is not credible, ie low when its obviously hot, or hot when its obviously still cold then this might need investigation. But as I say its just a suggestion.
                      Last edited by Bugman; 26-11-2018, 07:26 AM.

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                      • #12
                        Hi thanks for your reply on the diognostic it was reading a rich mixture so will check the temp sender about the only thing not changed.
                        regards

                        Comment


                        • #13
                          Another thought, thinking outside the box. How fresh is the petrol in the car? If the car was sitting around for a long time awaiting the repairs maybe the petrol has gone stale and the car is trying to run on what is now 80 octane petrol !

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                          • #14
                            When a petrol filter is starting to become clogged due to lack of service, you first notice it when pulling hard, as the car is demanding fuel and the filter is restricting the flow, - You probably wouldn't notice it at idle speed.

                            Regards

                            Comment


                            • #15
                              Hi did a cylinder leak test and found no4 cylinder was leaking on inlet valve could feel the air escaping, have taken the head off what an job ( not like working on the old classics 20 mins and you have the head off and no blood lost) need help to identifying the correct vale spring compressor as I see it is a deep head and small valves.
                              Regards

                              Comment

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