Egr valve and air leak

Davidkinton

Member
I’ve been having a series of problems with my 1.4 aua petrol. The fault code generated is an air leak detected. The symptoms are revs bouncing up and down at idle. All the lights have been lighting up on the dashboard. The strange thing is, when I unplug the egr valve, the engine runs much better and ticks over smoothly. It just throws up the epc and engine management light. I have tried replacing the egr valve with no improvement. Does anyone know why it runs better with the egr unplugged, and what might this suggest about the possible fault. Thanks for any advice.


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1583519050467.png

Check for loose bolts / nuts, air leak through pipe 4, leaking gaskets 3 or o ring 12. Leaking pipe 9 and check filter and tubing 10.
 
View attachment 61909
Check for loose bolts / nuts, air leak through pipe 4, leaking gaskets 3 or o ring 12. Leaking pipe 9 and check filter and tubing 10.

Thanks for image. I have checked most of these, but I have a suspicion that it might be the vacuum take off for the brake servo, but it’s very awkward to get to.


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Well there as good as it gets, do you have a throttle butterfly that could need cleaning (long time since i worked on vag petrols)
 
Well there as good as it gets, do you have a throttle butterfly that could need cleaning (long time since i worked on vag petrols)

Yes, I removed the throttle body and cleaned it a few months ago. I’ve booked it in with a specialist next week who’s going to have a look at it. He says that even the smallest air leak will cause problems.


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Best way to check for air leaks is with everything tight and spray carb cleaner around all components, an increase in idle speed indicates a air leak, smoke tester is also great but bit more expensive!
 
Best way to check for air leaks is with everything tight and spray carb cleaner around all components, an increase in idle speed indicates a air leak, smoke tester is also great but bit more expensive!

Yes I’m hoping that the specialist has a smoke tester as I think that would be the quickest way to pin point the leak. I’ve tried both carb cleaner and gas from a blow torch with no success. Access is very difficult on the aua inlet manifold.


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Just to close this topic, I took the car to a specialist and using a smoke tester, he diagnosed a small leak from the inlet manifold. I got a secondhand inlet manifold from eBay, which he duly fitted, and the car is now fine. No air leak, but it just shows that it’s not always simple things like a split hose for example.


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Just to close this topic, I took the car to a specialist and using a smoke tester, he diagnosed a small leak from the inlet manifold. I got a secondhand inlet manifold from eBay, which he duly fitted, and the car is now fine. No air leak, but it just shows that it’s not always simple things like a split hose for example.


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Hi,
I'm having a similar problem with my AUA 2002 A2, can I ask who you used to diagnose / fix the problem,

Best Regards

Anthony
 
Hi,
I'm having a similar problem with my AUA 2002 A2, can I ask who you used to diagnose / fix the problem,

Best Regards

Anthony

I had it looked at by a bloke called Paul who is an ex VW Master Technician with a garage in Boothtown, Halifax. His number is 07809 688742. He is very reasonable and managed to diagnose the manifold fault for me. Have you checked all the usual issues like hoses connected to the inlet manifold, dipstick tube fracture etc?


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Thanks for that, I’ll give him a call, it’s had a new pierburg egr, front + rear lambda sensors, in the past a throttle body clean etc, my mechanic did diagnose a slight air leak on a hose but to be honest since that was fixed it’s not run aswell as before, just plagued by the eml + slight hunting at idle
 
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