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  1. #1
    VXR newbie
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    Question Help with limp mode, Possible Overboost again again?

    Hello Everyone,
    i have an insignia VXR 2010 with MWP stage 2 kit and 2nd decat pipe.

    for the last 2 months it has been going into limp mode on hard acceleration. Now i have done some investigation but i have drawn a blank now and could do with some advice.

    I borrowed a friends diagnostic tool and the error code P0234 turbo overboost was present when in limp mode (resets on engine on/off). So i researched the issue (mainly on here) and
    I have checke the vacuum and pressure hoses around the boost solenoid
    I have replaced the pierburg boost solenoid for another pierbug one - no good
    I have replace the MAP sensor (albeit with a cheap one) - no good

    I have now linked the turbo actuator straight to the turbo so it will underboost if you like, i.e. open the wastegate early. This generally allows the car to get to 60% boost on the internal pressure gauge but on hard acceleration it still went into limp mode?

    So i am stumped now on what to do?

    i realise this is not a straight forward issue, can anyone suggest the next steps?

    Cheers guys i appreciate any thoughts or suggestions on the fault or on where i could take it, i am in castle donington (betwwen notts and derby)

  2. #2
    VXR enough dvinell's Avatar
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    Have you checked for air leaks downstream of the turbo?
    It seems like you have checked "everything electrical", whereas it could be something mechanical.
    The wastegate is an obvious starting point, but air leaks or damaged intercoolers can also cause strange problems causing the system to try to over-compensate.
    Last edited by dvinell; 13th April 2018 at 08:10 AM.

  3. #3
    VXRed blooded
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    hard acceleration is happening faster than the actuator can open so perhaps its sticking a little....so the map setpoint for high boost is being hit.... is the map a true stage 2 or a map 1 with decat mods.
    A true stage 2 map isnt the same as stage 1....the difference is minimal but can have side effects.

  4. #4
    Are you VXR enough? Dalle1985's Avatar
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    Yup, check that the wastegate arm is moving freely. You can try to remove the linkage to the WG actuator and then move the arm on the turbo. It should move with almost no resistance.

    It could also be the WG actuator itself which is gone... usually they fail because the spring breaks meaning the actuator won’t close properly, but if the bellow for opening the valve is blown for some reason, it will stay closed. But my money is on the WG itself. If you can exercise it, it might be enough to get it working again.
    2010 Insignia OPC Sports Tourer

  5. #5
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    Default Cheers guys

    Cheers for the tips guys.
    I have moved the waste gate and it moves fine and springs closed.

    When the waste gate is connected straight to the turbo the gauge only.gets to 60% boost but it still goes into limp mode? So the waste gate opens boost only achieves 60% but I still get limp mode?

    I guess these things are never straight forward, I checked the error codes again last week. And there were loads compared to the first time when it was just.over boost. Most of them were related to "voltage low" but it also had the "replace ecu" and "throttle position not learned".

    I thought this was because the battery was low but I think maybe it's something else?

    Sorry if this is getting messy but as you can tell it's a strange problem.

    I would upload a picture of the codes but I think I can only upload 64kb I doubt it will be readable that small.

    I will look for boost leaks but I'm not sure how I can over boost with leaks?

    With regards to the map I can't say for certain if it's stage 2 or 1. The invoice I have from the previous owner says stage 2.
    Some people have removed there map to sort the issue which I could do but it was fine for the previous 5 months so something has changed?

    Cheers for the replies guys.

  6. #6
    VXRed blooded
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    i guess you need someone with proper diagnostic kit to read live data whilst driving to compare your gauge to the map sensor.
    if they are close enough then its not a leak.
    has the air filter been changed... sometimes a different airflow meter reading messes with how the ecu allows boost.
    all those voltage etc issues... mmmm... how does the car start... quickly or a little slow... these cars cook batteries and the ME9 ecu hates poor battery voltage which creates all sorts of false sensor faults.
    has the battery and charging alt been checked out

  7. #7
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    I used a draper expert diagnostic tool. It's pretty good but the live data would not work so I will have ask around for an alternative.
    I will check the airfilter as that is a quick fix. As for the voltage, the car generally starts well, sometimes a little slower. I mostly do short journeys so I will give it a charge and re check the codes when I can borrow the diagnostic again. Hopefully they will go.
    Thanks German
    I will get back to you once I have done it.

  8. #8
    Are you VXR enough? Dalle1985's Avatar
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    What is the voltage? Not only when the car is off but also after you start? The voltage on a Modern AGM batteries drop off like a cliff if they are starting to fail. So it might start alright, but the voltage drops and that messes with the ECU.
    2010 Insignia OPC Sports Tourer

  9. #9
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    Cheers dalle
    I should have checked the battery before I charged it but after I charged it and since it was 12.6v and 12.4v. So pretty normal (car off).
    I am still waiting to get the diagnostic tool to interrogate the codes again.
    I checked the air filter which is a piper cross panel filter and it was pretty dirty. I cleaned off the grime from the top but I will look to get a new one I think. I'm not sure how that would cause the problem but I will change it anyway.

    On another line does anyone know a garage in the east midlands who would be good to take it too for a look??
    I am struggling to give it the time it needs to sort it this side of christmas!
    Cheers again

  10. #10
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    Thumbs down 2 trips to VX still no joy

    So a lot to update you on,

    i took it to vauxhall in nottingham chillwell for diagnostics, the tech plugged it in but due to battery voltage he said there were too many codes and he couldnt diagnose the fault. He spent half an hour to tell me nothing basically. we disccussed this at length but he still didn't shed any light on anything.

    on the way home about 1 mile from VX the clutch went completly, disaster!
    I would like your opinions on whether I should bring this up with vauxhall its a ridiculous coincidnece that 1 mile after their tech has the car, the clutch goes?? there was no issue with it before????

    7 days and £1500 later i am at vauxhall again (new clutch, flywheel and battery charged). When the guys who did the clutch returned it to me, they said the car was showing an O2 sensor fault, I thought it was something to do with the de-cat but the car is now bringing the engine management light on which it never did before?

    the vauxhall tech spent another hour on the car only to tell me the O2 sensor was faulty (which i told his boss when i dropped the car off) and that he couldn't go any further as that fault was preventing him.

    he admits though that the car is also bringning up over boost and under boost at the same time as the O2 sensor fault so couldnt say for sure that this was the problem???

    Question then guys for help

    can the O2 heater fault sensor cause limp mode?
    does the car use overboost and underboost codes to protect itself even if this is not the problem?

    should VX be paying for my clutch?

    cheers again guys
    Last edited by guin; 4th May 2018 at 08:57 PM.

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