mclarenm8d

I will just have to double-check your guys' planned schedule against anything I may have going on.

Thanks!

KMU

that you can see injector pulses with an led tester and the suspect injector unplugged with the car "running."(at least temporarily) I suppose there could be something proprietary about Audi's approach,I don't know. The easist thing to do from a failure frequency standpoint is swap ecu's(again,my experince with other makes). This really requires a trusting donor I know,and often isn't readily available. Without that luxury, a logical process of elimination is my only approach. This would be my sequence. 1-make sure plug is good(swap w/known firing one), 2- swap w/ known firing coil, 3- verify firing signal to coil.( one could take the suspect coil loose with it still plugged up, plug a spare spark plug in it, ground the threaded portion of the plug w/ a jumper wire to a good engine ground and observe while cranking. Hands off! Secondary spark voltage could be dangerous.) 4- Ohm test all injectors(if they are all same, I would either swap, flow-test for correct pressure drop, or make the leap of faith that the ohm test at least verifies electrical integrity. 5-check injector supply voltage wire with voltmeter and return ground path w/ ohmeter. If all that checks, I bet it's the ecu. There are 8 switching grounds in there and failure of one I bet isn't uncommon. A good Audi or import tech will tell you what he has seen fail the the most, and although that sometimes ia a costly assumption, you know the alternative-DEALER. When in doubt, go with the most likely. Not trying to just overstate the obvious, but if the sequence of diagnosis gets of whack, often the result is. Hope this helps.

airbil

are you sure this is the ecu?
I thought the ECU has the one lever type connection, the vertical (inboard) box, towards drivers side. It has a big silver metal lever that connects the wires, kinda like a big ZIF connector.
I dont see an eprom in these pics, though there are a lotta wires connected to it.

escapA8

Pic of plug coming soon!

PaulW

In the box there is the ECU on the left, then the cruise control module (silver one), then the transmission control unit on the right.

<img src="http://pictureposter.audiworld.com/22012/dsc03713.jpg">

KMU

plug out. Very unlikely,but first things first.

escapA8

<center><img src="http://pictureposter.audiworld.com/31455/escapa8_spark_plug_misfire_cyl_2.jpg"></center><p>

KMU

worth anything.(not fron Bentley) Might follow that circuit back if you have board out of ecu box. The voltage supply to the injectors is a common wire controlled by one fuse. Get rid of that plug. I don't understand why it would be black if it's not supplying fuel at all. You said it only misfires at certain rpm's?

ryoung

I having a hard time imagining a scenario where lack of fuel from an injector problem could produce the soot that you see on the electrodes.