VXOC Astra-J/GTC

Hi all,

After a previous post about intermittent lack of power, and having replaced the EGR valve with a brand new one, another fault or previous one now getting worse.
In gears 4-6 if the revs are below 1500 rpm there is a pronounced juddering from the engine at any throttle input until about 1800 rpm but it’s more pronounced in 5th and 6th. I’ve physically checked the turbo and it’s free with no excess play, the vacuum pipes are all whole as far as I can tell, the swirl flap actuator is free and I have seen it moving but only when shutting the engine down. No fault codes found using code reader. I’ve a feeling it could be a vacuum operated type fault controlling turbo boost. Looking for some help from anyone who has experienced this type of fault previously.

Any help greatly appreciated.

Ps don’t have any diagnostic gear other than a basic engine code reader any recommendations for an adequate piece of kit would be helpful.

Cheers

Mark


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I'm guessing your doing low speed for the gear?

In terms of kit op-com would the better thing to buy.

Hi Rusty,

That’s right, in gears 4-6 if the revs are below about 1800 it shudders a bit like a misfire, it’s only slight in fourth but in fifth and sixth it’s far more pronounced. I’ve taken the vacuum solenoid for the wastegate off and cleaned the little filter, checked the resistance through it and across the pins and all seems well. Next step is to clean out the maf sensor and find some figures to measure resistance. Also thinking it might be worth checking the injector leak off rates too as it’s a bit noisy and roughat start up

Been looking at opcom but seems too many scam sellers about can you recommend a reliable source for supply. I use a Mac and I know it’s only suitable for windows but could install it on a windows laptop I have lying around but what’s its limits with the operating system it needs ?

Cheers in advance for any help or info


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What engine have you got?

Sorry for the late reply I’ve only just saw that you had replied. I never got a notification for your reply. My engine is A17DTR. Still drawing a blank at the moment I’ve cleaned out the MAF and MAP sensors refitted the old SCV valve as I had bought a fake one and my performance was poor, fitting the old one back in has increased how it performs but the judder remains.


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Just throwing something in here, you could have a failing injector or fuel filter may need changing. It's another avenue to look at. I think really you need diag session.

Changed the filter about 7k ago so shouldn’t really be due. I’m in the process of trying to sort out diagnostic kit at the moment but running out of time before heading back to work for three weeks on Monday. Will have to wait until I return.


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