Injectors wont fire , no signal

There will only be a voltage on the injector when the ECU knows the engine is rotating, and so opens one injector at a time, when the crankshaft sensor shows that cylinder is ready. That will only be for a very short time, and probably wouldn't show on a multi meter, except, perhaps if set to read maximum voltage, which some meters can. So no voltage with ignition on is normal.
The ECU will only open the injector if it knows the engine is rotating, that why the rev counter check is important.
When you turn the key to the first position, do all the dash lights come on, and does then DIS show OK?
When you try to start the engine, it turns over, what rpm? Does it try to fire, or just turn? When did it last run, and what happened since?
Sorry for the questions, but we need to form a picture, in order to help.
Mac.
When I was checking my crank sensor I removed the spark plugs to give a quicker cranking speed. No question the rev counter was at about 800rpm!
 
All wiring looks factory .
The engine has been replaced with a earlier AUA engine , with BBY ancillaries connected from the original BBY engine .
Audi has confirmed the bare blocks are the same ..
 
All wiring looks factory .
The engine has been replaced with a earlier AUA engine , with BBY ancillaries connected from the original BBY engine .
Audi has confirmed the bare blocks are the same ..
If the BBY is fitted, as a replacement for the original AUA, the ECU must also be a BBY part and the loom from the ECU to the ignition coils must be from the BBY donor car, as the AUA has only two spark triggers, (it fires two cylinders at the same time), whereas the BBY requires four separate trigger wires. There may be other differences too, but the ECU/Coil is relevant to your symptoms, I think.
Mac.
Edit: The fuel supply and return system in the original AUA are very different in the BBY.
The AUA has a return path, while the BBY does not. So, the pipework from the tank to the fuel rail, (and removing the return in the AUA), including the filter has to be changed to suit the BBY.
Mac.
 
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Original engine was BBY .
The new ingine is AUA but with all the ancillaried from the original BBY engine .
Hope that clears up things.
Audi told me both engines are the d
same .
 
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Original engine was BBY .
The new ingine is AUA but with all the ancillaried from the original BBY engine .
Hope that clears up things
Basic comments apply, but in reverse.
The big differences in the fuel systems need to be fully understood, and dealt with. That includes the additional fuel return line to the tank, the filter, etc
I also wonder if the AUA crankshaft sensor is fully compatible with the BBY ECU, (which must be fitted).
Mac.
 
Im not getting any crank sensor faults .
When you crank the engine the rev counter shows about 200rpm
Apologies if this has been answered already but, when you say it’s an AUA with BBY ancillaries, does that include the ECU?
 
Your engine is not an AUA. It's a hybrid, of AUA and BBY, and I think that's very significant. My apologies, as I had not fully realised this till now.
You have an AUA main engine, block and head, but with a BBY fuel rail, and ignition coils fitted.
Although the AUA and BBY engines are very similar, I have doubts that simply fitting BBY ignition coils, and a BBY fuel rail to an AUA engine, will make it a "plug & play" BBY compatible engine. Of course, I don't know, and I don't think anyone else does.
As it was a non runner when you got it, we don't know, for sure, if it was ever running well after the engine swap. This makes troubleshooting incredibly difficult, as there is no reference point to work from.
Careful study of the A2-Freun.de post maybe a good place to start.
Mac.
 
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Your engine is not an AUA. It's a hybrid, of AUA and BBY, and I think that's very significant. My apologies, as I had not fully realised this till now.
You have an AUA main engine, block and head, but with a BBY fuel rail, and ignition coils fitted.
Although the AUA and BBY engines are very similar, I have doubts that simply fitting BBY ignition coils, and a BBY fuel rail to an AUA engine, will make it a "plug & play" BBY compatible engine. Of course, I don't know, and I don't think anyone else does.
As it was a non runner when you got it, we don't know, for sure, if it was ever running well after the engine swap. This makes troubleshooting incredibly difficult, as there is no reference point to work from.
Careful study of the A2-Freun.de post maybe a good place to start.
Mac.
As I understand it it’s a pure BBY.
The original engine was BBY, so the wiring loom and ECU are BBY.
The ancillaries, and all parts that differ between AUA and BBY are from the original BBY.
If I understand correctly, the only AUA bit is the engine block/head, which is physically identical to the BBY version, so for all intents and purposes it’s a BBY.

I believe @Azim also said that the engine has been running in its current setup too, though maybe I’m getting it confused with a different thread.
 
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As I understand it it’s a pure BBY.
The original engine was BBY, so the wiring loom and ECU are BBY.
The ancillaries, and all parts that differ between AUA and BBY are from the original BBY.
If I understand correctly, the only AUA bit is the engine block/head, which is physically identical to the BBY version, so for all intents and purposes it’s a BBY.

I believe @Azim also said that the engine has been running in its current setup too, though maybe I’m getting it confused with a different thread.
It was a non runner:
You could be right, the AUA and BBY are very similar, so fitting BBY coil packs and fuel rail maybe all that's needed to convert an AUA to a BBY.
Just seems too simplistic to me. Hopefully, I'm wrong, it has been known!
Mac.
 
It was a non runner:
You could be right, the AUA and BBY are very similar, so fitting BBY coil packs and fuel rail maybe all that's needed to convert an AUA to a BBY.
Just seems too simplistic to me. Hopefully, I'm wrong, it has been known!
Mac.
Ahh yeah fair enough, if it hasn’t run since the conversion then that certainly would seem like the place to start.
 
Your engine is not an AUA. It's a hybrid, of AUA and BBY, and I think that's very significant. My apologies, as I had not fully realised this till now.
You have an AUA main engine, block and head, but with a BBY fuel rail, and ignition coils fitted.
Although the AUA and BBY engines are very similar, I have doubts that simply fitting BBY ignition coils, and a BBY fuel rail to an AUA engine, will make it a "plug & play" BBY compatible engine. Of course, I don't know, and I don't think anyone else does.
As it was a non runner when you got it, we don't know, for sure, if it was ever running well after the engine swap. This makes troubleshooting incredibly difficult, as there is no reference point to work from.
Careful study of the A2-Freun.de post maybe a good place to start.
Mac.
It did run when i first got the car , how ever it felt like it was on 3 cylinders
So i decided to replace all the spark plugs for new items .
After this the car failed to start ...
 
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