1.4 petrol poor idle issues

[Azim]

My thought is that the AUA crank sensor, and the ring have a different sensitivity, compared to the BBY combination, (maybe smaller diameter ring, or longer sensor). So, the BBY sensor isn't being fully triggered by the AUA ring. The magnetic effect is increased with engine speed, so once the engine fires, it'll run, sort of, but misfiring, because of the weak crank signal.
I accept this is all theoretical. Maybe, a vcds log of the engine speed would help, but I'm not sure.
Changing the sensor is not a big job, but finding the correct replacement is the first task.
Mac.

Ive been told by 3 seperate audi dealers that the parts are the same between the BBY car and the AUA car .
Does that not rule out that the rings are not different sizes.
With only possible diffence being the crank sensor being square or rounded shaped .

 

[PlasticMac]

Ive been told by 3 seperate audi dealers that the parts are the same between the BBY car and the AUA car .
Does that not rule out that the rings are not different sizes.
With only possible diffence being the crank sensor .

We can't be sure about the ring being different, because it's only listed as part of the crankshaft seal assembly. It's, probably the same, as there's no logic in changing the design part way through the engine's production life, as AUA then BBY.
If the previous owner had fitted a complete BBY, instead of just the top half, I think there would have been no problem.
The Audi dealers are wrong. See my previous post, and this picture, showing two different versions of the AUA engine speed senders, one round and the other square:

Mac.

 

[Azim]

We can't be sure about the ring being different, because it's only listed as part of the crankshaft seal assembly. It's, probably the same, as there's no logic in changing the design part way through the engine's production life, as AUA then BBY.
If the previous owner had fitted a complete BBY, instead of just the top half, I think there would have been no problem.
The Audi dealers are wrong. See my previous post, and this picture, showing two different versions of the AUA engine speed senders, one round and the other square:
View attachment 117188
Mac.

The original owner replaced a complete engine from BBY to AUA,.
The ignition system seems to be from the later BBY engine ( individual coil packs ).
So I have to find out which sensors are fitted.
And if they need to be changed .

 

[PlasticMac]

The original owner replaced a complete engine from BBY to AUA,.
The ignition system seems to be from the later BBY engine ( individual coil packs ).
So I have to find out which sensors are fitted.
And if they need to be changed .

So, the only BBY parts are the ECU, associated looms, and coil packs. Correct?
If so, the BBY ECU will expect to see a signal from a Version II AUA/BBY speed sender, or a BBY specific sender. The BBY specific item is round, so, won't fit the AUA's square entry, so would have to be the square Version II AUA/BBY part
So, you're looking for the Version II, (square), AUA/BBY speed sender/aka crankshaft sensor..
My assumption, is that the sender currently fitted is the AUA specific part.
I really think we'll go round in circles unless someone take's a look at the engine speed sensor, G28 measuring block, in VCDS, to so see if there is a good signal present, or not, (or swaps out the engine speed sender, for the AUA/BBY version).
VCDS is the quickest and cheapest way to diagnose whether the problem is the crankshaft sensor, or elsewhere.
The camshaft sensor G40 is also a suspect, but I can't find that in VCDS, but Group 003, Ignition,Timing Angle, Specification, might give a clue, worth a look, but check the crank sensor out first.
Mac.

 

[Azim]

So, the only BBY parts are the ECU, associated looms, and coil packs. Correct?
If so, the BBY ECU will expect to see a signal from a Version II AUA/BBY speed sender, or a BBY specific sender. The BBY specific item is round, so, won't fit the AUA's square entry, so would have to be the square Version II AUA/BBY part
So, you're looking for the Version II, (square), AUA/BBY speed sender/aka crankshaft sensor..
My assumption, is that the sender currently fitted is the AUA specific part.
I really think we'll go round in circles unless someone take's a look at the engine speed sensor, G28 measuring block, in VCDS, to so see if there is a good signal present, or not, (or swaps out the engine speed sender, for the AUA/BBY version).
VCDS is the quickest and cheapest way to diagnose whether the problem is the crankshaft sensor, or elsewhere.
The camshaft sensor G40 is also a suspect, but I can't find that in VCDS, but Group 003, Ignition,Timing Angle, Specification, might give a clue, worth a look, but check the crank sensor out first.
Ma

So, the only BBY parts are the ECU, associated looms, and coil packs. Correct?
If so, the BBY ECU will expect to see a signal from a Version II AUA/BBY speed sender, or a BBY specific sender. The BBY specific item is round, so, won't fit the AUA's square entry, so would have to be the square Version II AUA/BBY part
So, you're looking for the Version II, (square), AUA/BBY speed sender/aka crankshaft sensor..
My assumption, is that the sender currently fitted is the AUA specific part.
I really think we'll go round in circles unless someone take's a look at the engine speed sensor, G28 measuring block, in VCDS, to so see if there is a good signal present, or not, (or swaps out the engine speed sender, for the AUA/BBY version).
VCDS is the quickest and cheapest way to diagnose whether the problem is the crankshaft sensor, or elsewhere.
The camshaft sensor G40 is also a suspect, but I can't find that in VCDS, but Group 003, Ignition,Timing Angle, Specification, might give a clue, worth a look, but check the crank sensor out first.
Mac.

I have vcd, but im not a expert at using the software .
I can check on the type of crankshaft sensor fitted .
I will need help to use my vag com to determine if I have a good signal or not .
After that I can determine a course of action .
Is there anybody local to coventry who can help me to determine if weather I have a good signal or not ?.

 

[birtyA2]

Hi Azim

I put a link to the scan register on post 18. Hopefully there will be someone close to you in there

J

 

[Azim]

ok .
I will take another look and see if anyone is near to me

 

[PlasticMac]

Good morning. I've realised that VCDS won't help check the crankshaft sensor. The engine speed measuring block shows RPM, so is an ECU output, not the actual sensor input.
So, I went back to basics, sparks and fuel. Having done sparks to death, with the crankshaft sensor, etc, I looked again at fuel.
There seems to be two variants of the BBY, a cross over, (AUA to BBY), version, and a pure BBY version.
There are two different fuel rail assemblies listed, (on 7 Zap). One is shown as AUA/BBY, while the other is BBY only.
They look a bit different, (see pics below), especially the pressure regulator. ( @Azim could you have a look, to check which one your car has please?)
There are two different injectors listed, (in 7Zap) for the AUA/BBY engines, one being 036906031M (Oval), the other 036 906 031C (Rectangular).
So, a closer look at the two fuel rail/injector assemblies is in order.
Mac.

This is the BBY specific asst:

This is the AUA/BBY assy:

 

[birtyA2]

Good morning. I've realised that VCDS won't help check the crankshaft sensor. The engine speed measuring block shows RPM, so is an ECU output, not the actual sensor input.
So, I went back to basics, sparks and fuel. Having done sparks to death, with the crankshaft sensor, etc, I looked again at fuel.
There seems to be two variants of the BBY, a cross over, (AUA to BBY), version, and a pure BBY version.
There are two different fuel rail assemblies listed, (on 7 Zap). One is shown as AUA/BBY, while the other is BBY only.
They look a bit different, (see pics below), especially the pressure regulator. ( @Azim could you have a look, to check which one your car has please?)
There are two different injectors listed, (in 7Zap) for the AUA/BBY engines, one being 036906031M (Oval), the other 036 906 031C (Rectangular).
So, a closer look at the two fuel rail/injector assemblies is in order.
Mac.

This is the BBY specific asst:
View attachment 117214


This is the AUA/BBY assy:
View attachment 117215

They are indeed. Have a look at the link to the German wiki. From that a quick check would be; is the rail aluminium (AUA) or plastic (BBY) or check the fuel filter for two connections or three.

 

[PlasticMac]

They are indeed. Have a look at the link to the German wiki. From that a quick check would be; is the rail aluminium (AUA) or plastic (BBY) or check the fuel filter for two connections or three.

Do you have the link please?
Mac.

 

[Azim]

Good morning. I've realised that VCDS won't help check the crankshaft sensor. The engine speed measuring block shows RPM, so is an ECU output, not the actual sensor input.
So, I went back to basics, sparks and fuel. Having done sparks to death, with the crankshaft sensor, etc, I looked again at fuel.
There seems to be two variants of the BBY, a cross over, (AUA to BBY), version, and a pure BBY version.
There are two different fuel rail assemblies listed, (on 7 Zap). One is shown as AUA/BBY, while the other is BBY only.
They look a bit different, (see pics below), especially the pressure regulator. ( @Azim could you have a look, to check which one your car has please?)
There are two different injectors listed, (in 7Zap) for the AUA/BBY engines, one being 036906031M (Oval), the other 036 906 031C (Rectangular).
So, a closer look at the two fuel rail/injector assemblies is in order.
Mac.

This is the BBY specific asst:
View attachment 117214


This is the AUA/BBY assy:
View attachment 117215

Morning .
I will look at these two items some time today .
As I am replying to you , I was looking at you tube video's on vcd measuring blocks .
Thinking this was what I needed to do to make sure I was getting the required signals from the crankshaft sensors .
The question I have bearing in mind the engine does not start .
How and what do I need to do to obtain the said signals .
1 crank the engine .
2 or rotate the engine by hand ..

 

[Azim]

My fuel rail seems to be the BBY fuel rail in the 1st pic .
How ever it doesnt have item no10 in one end of the rail ...
Also ive found a very loose fitting fuel pipe , which connects to the fuel intake.
Im going to the motor factors to geta new fuel pipe as this is very loose when fitted

 

[birtyA2]

Do you have the link please?
Mac.

Hi Mac

post 49 on this thread

J

 

[birtyA2]

My fuel rail seems to be the BBY fuel rail in the 1st pic .
How ever it doesnt have item no10 in one end of the rail ...
Also ive found a very loose fitting fuel pipe , which connects to the fuel intake.
Im going to the motor factors to geta new fuel pipe as this is very loose when fitted

Hi Azim
I would say it is a BBY fuel rail and as such will not have Item 10 which is AUA specific. If you look at the post 49 from the German club there are some side by side comparison photos

J

 

[PlasticMac]

Hi Azim
I would say it is a BBY fuel rail and as such will not have Item 10 which is AUA specific. If you look at the post 49 from the German club there are some side by side comparison photos

J

I agree, and the info in the German Club post describes the difference very clearly.
Maybe a wanted post, for a AUA fuel rail, in the Market Place is worth a go.
Mac.

 

[PlasticMac]

*

Hi Azim
I would say it is a BBY fuel rail and as such will not have Item 10 which is AUA specific. If you look at the post 49 from the German club there are some side by side comparison photos

J

I do hope this car stays in The A2 Owners Club fold, once it's mystery is revealed.
Mac.

 

[Joga]

I agree, and the info in the German Club post describes the difference very clearly.
Maybe a wanted post, for a AUA fuel rail, in the Market Place is worth a go.
Mac.

If I understood this correct this is a BBY car which has had the (BBY) engine exchanged to a AUA engine, which had had the AUA unique parts exchanged to the corresponding BBY parts from the original engine.
All with the purpose of letting the car and its system including the engine ecu to keep thinking it is still a BBY engine (which it more or less actually is).
Therefore it would be no use to look for any AUA parts in this situation.

 

[Joga]

My fuel rail seems to be the BBY fuel rail in the 1st pic .
How ever it doesnt have item no10 in one end of the rail ...
Also ive found a very loose fitting fuel pipe , which connects to the fuel intake.
Im going to the motor factors to geta new fuel pipe as this is very loose when fitted

Item 10 in the BBY view is most likely an manual pressure relief / air purge valve (similar to the Schraeder valve of a tyre).
Cant see why anyone would have removed it on purpose, have you looked for it in the rail end nearest to the throttle?

 

[PlasticMac]

There seems to have been an interim version of the BBY, which has the BBY individual coil packs, but not the BBY non return fuel system. I formed this view from there being a fuel rail, with the return circuit, listed as being AUA and BBY compatible, and a version 2 of the crankshaft sensor, which is square, to fit the AUA housing, and is also listed as AUA and BBY compatible. There's a round crankshaft sensor too, but that is BBY only.
I guess Audi had a lot of AUA parts that they wanted to use up.
The relavance of all that to the @Azim car, is that by fitting the original fuel rail, with the return circuit, to his car, the fuel system will match that interim BBY build.
We don't know if the crankshaft sensor also needs to be of the interim, version 2, square type.
Since the car is a BBY build, with BBY ECU, etc, but now fitted with an AUA engine, making the AUA engine mimic the BBY seems to be the way to get it running.
Hope this makes sense @Joga
I think the darkened room beckons ...
Mac.

 

[Azim]

I agree, and the info in the German Club post describes the difference very clearly.
Maybe a wanted post, for a AUA fuel rail, in the Market Place is worth a go.

Item 10 in the BBY view is most likely an manual pressure relief / air purge valve (similar to the Schraeder valve of a tyre).
Cant see why anyone would have removed it on purpose, have you looked for it in the rail end nearest to the throttle?

Do you mean this side .
It seems like this side does not have any valves fitted either ..