meternerd

If you are reading to a solid ground (use the negative battery terminal to be sure), you can ignore the 2.79V. There is really nothing in the car that runs on anything less than 12V until you get to sensor outputs and the like. If you're using a high impedance (digital) meter, you're reading what's known as "Phantom Voltage".

There's really no power there....that's why you are reading it everywhere. If you can get to the fuse terminals with the fuse still plugged in, read each fuse line side and load side to ground. Try with the key off, on and in the start position. Any that don't show the same voltage on the line and load side are blown. If it will start with starting fluid means the ignition is OK and you at least have a fuel problem. You need to figure out where the power to the fuel pump is being lost. Fuse, relay, etc. Audi wiring diagrams are a real beast to follow and if you're unfamiliar with schematics and wiring diagrams, you might want to get help from someone who's tech savvy. But mainly. you need to get power to the fuel pump, then if it starts, you can go from there. If you have fuel from the pump, then electronics controlling the injectors are the next step. I'm betting your fuel pump is not working. Resistance reading (Ohms) is really only useful when looking for bad grounds or blown fuses. Reading resistance on any electronics is dangerous because the meter applies voltage to the circuit and is not likely to show a problem anyway. Patience is what helps (and a can of beer doesn't hurt either). Good luck.

meternerd

The relay panel called a 3-fold relay panel is next to the ECM under the black plastic shroud, outboard of the brake booster, according to my Bentley's manual. Mine is a 2001 2.7T and that's where it is on mine. There's a screwed on black plastic cover with a (bulge) in one corner. But...there's a note saying different models and years have components in different locations. Why make it easy!

Jwacker86

I pulled the fuel line and turned it over and fuel came out. Was thinking it was injectors not opening so changed cam positioning sensor but nothing. Hooked up scanner and have no reply from computer.

meternerd

Ok....so now you know it's probably not a fuel SUPPLY problem. Next is to see if it will fire. Just use starter fluid or gas in a squirt bottle or even an unlit propane torch (BE CAREFUL) and with the engine cranking (it'll take a helper), squirt some in the intake where the flex tube connects to the MAF. It should at least try to run, since you said you had spark. If you get nothing, then I'm kinda out of ideas. You need spark, fuel mix and compression for an engine to run. If it fires, then you can move on to injectors. You'll have to keep digging 'till you find out which ones you're missing. Just buying parts 'till you luck out and find the problem can get VERY expensive. You need to verify you have power to the ECM. To do that, you'll need a wiring diagram for your car. The generic Bentley's may not be a lot of help. Seems like it covers a variety of models and years with just one manual, but the basics of fuse and relay components is probably similar, just in different locations. Since it doesn't seem to be the fuel pump, the next suspect is the ECM, and that's not an easy thing to troubleshoot. No comms to the OBDII port is not good news. Since the ECM controls pretty much everything, you need to get it "talking" before you buy any more parts. You may have to resort to a shop that has the equipment to do a full diagnosis.....but the question is, how much can you afford to spend to get it running. That's a question only you can answer.

One comment.....after reading your post, I went and put red markers on the battery cover and the positive terminal of the battery in hopes of not making the same mistake. Doesn't help you, but it might clue the rest of us to connect it right, even when we're in a hurry, in the dark and late for work. Don't give up, and make sure you keep us all up to date on your progress.