Help with Audi Injector wire?(Not Audi specific?)
 

I know which wires are which, but I'm not sure which of them I'm supposed to be tapping into, so this question shouldn't be so model specific (1998 A4 2.8qm)...

I've read that I should be tapping into the wire that reads 0v when the engine is off, and I've seen some other suggestions for other arrangements that don't seem to apply here, so I'm sorry if this is a stupid question.

Looking at the ECU/ECM wiring schematics in my bentley manual, there are many levels of wiring that I could tap into:

-"Level 1" Would mean tapping into one of the 6 apparent leads between the ECU and the ECM.
-"Level 2" Would mean tapping into one of the six leads from the ECM to the injectors themselves.
-"Level 3" (What I hope is it) Would mean tapping into the lead connecting all 6 injectors, the wiring harness (over fuse 229, apparently), and the ECU.

Which level should I tap into? With engine off, I can find 0v on leads at each level...

Also, I realize that finding the lead that measures 0v is my objective, but at the moment I don't know which lead measuring 0v to use.

I would go for the one near the ecu just to keep it indoors.

You want to connect to one of the leads that are connected to the injector. It *may* read 0 volts when unplugged from the injector but with the ignition on and the engine off. For your sequential injection engine, it should not be the common injector lead.

I don't know this one, but it's not our target, I believe.
Do you mean there are six lines connected to the each injectors?
If so, one of six lines is the target wire.
Do you mean this is a single line from the ECU connected to all six injectors?
If so, I think this one is 12V power to injectors.

Yoshi