Hello everyone New member with a seemingly unsolvable problem...


Just recently decided to buy a used Audi A4 2.7 tdi 6 speed manual ( year 2006) with a problem... was a dirt cheap car due to this issue. Seller said "Slight shake at idle and gray smoke the first couple minutes after start". Suspected it will be an injector issue and went to look at the car armed with VCDS. Did a scan and checked the Injector Quantity Deviation values and sure enough Cylinder 2 and 4 were totally out of spec. Bought the car, took it home on a hour long drive. While driving the car would noticeably shake with acceleration under 1500 rpm higher rpm and its fine... was sure its going to be injector swap. Ordered 2 second hand injectors of ebay and installed them to replace Cylinder 2 and 4. Coded the new injectors to the ecu all fine. But no change with the issue whatsoever!!

When first looked at Injector Quantity Deviation values cyl 2 was at -5.27 mg/str and cyl 4 was at 5.04 mg/str

but it hasn't changed a lot now after replacing them cyl 2 is at -4.05 mg/str and cyl 4 is at 5.04 mg/str again!

What are the chances I have bought injectors with the same wear as I had before... I think slim to none right?


Attached file - I have logged Injector Quantity Deviation values on a pdf. file and color coded it to be red at both extremes and green at 0 correction


Also have a fault code for all 6 glow plugs, but the car starts with no problem every time even at -3c

And a fault code on Intake Manifold Runner Bank 2


On the attached file at time stamps 8.31 - 11.17 I revved the engine to max you can see how cyl 2 comes to acceptable Injector Quantity Deviation value but then settles back to - 3.95 mg/str soon after.

Next I'm trying to swap injectors from cly. 1 to cly 2 and see if the issue swaps around if not I'm lost here then, as the shaking is irritable when standing in traffic and have to drive it at higher rpm not to notice the shake...

Any ideas what's going on here?


Thanks!