1.4 petrol poor idle issues

The difficulty we have right now is that we don't know if the trigger ring for AUA and BBY are different.
Finding this out, would be my priority, but I have no idea how, other than a short log of one rotation of the crankshaft sensor on a good BBY and the same from a good AUA. If they are the same, then we can discount the ring. If they are different, we may be on to something.
The other route is to find a detailed lower engine parts list, that shows the ring as a part.
Robin_Cox said:
Bit of a parts number swerve, but is it possible that if you get the appropriate flange / seal component that it has the appropriate magnets integrated into the seal for the sensor to detect (similar to ABS rings inside the hubs)? So you just need the one-piece seal component?

ie, a similar part on the 1.9tdi :


so we don't need to know the part number for the trigger ring itself as it should be built in.
Click to expand...
Yes Robin, I reckon you're right. If so, there will be two part numbers for that assembly, and 7Zap indicates that there are, but I couldn't link the two seal assys part numbers to either AUA or BBY engines. I think I'll take a screen break for now, and a fresh pair of eyes might crack it.
I think the crankshaft trigger ring/sensor/ECU relationship is the first thing to establish.
If they are different, I can't see that it's likely to have been changed during the engine swap.

Could pop an AUA ECU and coil pack on there I suppose ... might just work ... and much easier then fitting a new ring.

Back tomorrow.
Mac.
 
When I read what I'd posted, about popping an AUA ECU and coil pack on there, I thought, hang on...
Surely the wiring/connections to the single ignition coil on the AUA must be quite different to the wiring/connections to the four individual coil packs on a BBY?
How has that adaptation been achieved, new loom, or cut'n'shut?
The schematics I have don't include the AUA, can anyone check please?
Mac.
 
Is this the car?

Engine replacement from AUA to BBY

Hi! As some of you probably know I bought a 02' 1.4 A2 with an AUA engine that is bad. I am mainly looking for a good 1.4 tdi car with good service history now, but have been offered a BBY engine (A2 platform) for fair price. Does anybody have a guide for engine swapping from AUA - > BBY? Have...
www.a2oc.net www.a2oc.net
Mac.
Not unless it travelled from Norway!
Mac.
 
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PlasticMac said:
When I read what I'd posted, about popping an AUA ECU and coil pack on there, I thought, hang on...
Surely the wiring/connections to the single ignition coil on the AUA must be quite different to the wiring/connections to the four individual coil packs on a BBY?
How has that adaptation been achieved, new loom, or cut'n'shut?
The schematics I have don't include the AUA, can anyone check please?
Mac.
Click to expand...
I can confirm no cut and shut has taken place .
 
PlasticMac said:
When I read what I'd posted, about popping an AUA ECU and coil pack on there, I thought, hang on...
Surely the wiring/connections to the single ignition coil on the AUA must be quite different to the wiring/connections to the four individual coil packs on a BBY?
How has that adaptation been achieved, new loom, or cut'n'shut?
The schematics I have don't include the AUA, can anyone check please?
Mac.
Click to expand...
Hi Mac

Yes the BBY has a different engine wiring loom. As this was a BBY and the engine has been swapped for an AUA but with parts from the original BBY swapped in I’m thinking this makes it a BBY to all intents and purposes. That said the two possible timing rings is an interesting development; but it has been running as it is ( all be it with poor idle ) so checking the cam sensor makes sense to me. The other possibility would be swapping back the original spark plugs as that seems to be the trigger for it going from running badly to not even starting

J
 
birtyA2 said:
Hi Mac

Yes the BBY has a different engine wiring loom. As this was a BBY and the engine has been swapped for an AUA but with parts from the original BBY swapped in I’m thinking this makes it a BBY to all intents and purposes. That said the two possible timing rings is an interesting development; but it has been running as it is ( all be it with poor idle ) so checking the cam sensor makes sense to me. The other possibility would be swapping back the original spark plugs as that seems to be the trigger for it going from running badly to not even starting

J
Click to expand...
I will try the original spark plugs as soon as weather permits .
 
birtyA2 said:
Hi Mac

Yes the BBY has a different engine wiring loom. As this was a BBY and the engine has been swapped for an AUA but with parts from the original BBY swapped in I’m thinking this makes it a BBY to all intents and purposes. That said the two possible timing rings is an interesting development; but it has been running as it is ( all be it with poor idle ) so checking the cam sensor makes sense to me. The other possibility would be swapping back the original spark plugs as that seems to be the trigger for it going from running badly to not even starting

J
Click to expand...
Sounds sensible. Having thought about the trigger ring, and sensor, my guess is that if they are different then it's likely not to be the number of segments, more likely the AUA ring needs the AUA sensor. As the complete BBY loom was fitted, I wonder if that included the BBY crank sensor?
If the sensors are different, maybe the connector is different too?
Questions that I can't answer, sadly.
Whatever it is, as you suggested, it is something that's marginal, and once fixed, I think the engine will run OK.
Mac.
 
I have been in touch with Audi dealers this morning and they have confirmed that both the spark plugs and timing rings on both engines BBY and AUA are the same .
 
Azim said:
I have been in touch with Audi dealers this morning and they have confirmed that both the spark plugs and timing rings on both engines BBY and AUA are the same .
Click to expand...
Any chance to ask them to confirm the crankshaft sensors are also the same please? We can rule that area out completely then 🤞
Mac.
 
PlasticMac said:
Any chance to ask them to confirm the crankshaft sensors are also the same please? We can rule that area out completely then 🤞
Mac.
Click to expand...
I have just come off the line to a 2nd Audi dealer , who told me that the spark plugs are the same but the timing rings are in fact different ..
 
Azim said:
I have just come off the line to a 2nd Audi dealer , who told me that the spark plugs are the same but the timing rings are in fact different ..
Click to expand...
This post indicates the AUA sensor, at least, maybe the ring too, has two versions. Early engines have AUA specific parts, while late AUAs, (at the point of AUA to BBY change, probably), had the same part as the BBY engine.
Post in thread 'which crank position sensor! ' https://www.a2oc.net/community/index.php?threads/which-crank-position-sensor.37683/post-331396
Mac.
 
Im on the phone to a 3rd Audi dealer right now .
Will update very soon.

Update ....
They told me the spark plugs timing ring crank and camshaft sensor are the same .
Only the ignition side is different with the AUA having leads and the BBY having coil packs.

I guess im still not sure if the timing ring is the same between the two engines .
With only one dealer saying that they are different between the two engines .
 
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Azim said:
Im on the phone to a 3rd Audi dealer right now .
Will update very soon.

Update ....
They told me the spark plugs timing ring crank and camshaft sensor are the same .
Only the ignition side is different with the AUA having leads and the BBY having coil packs.

I guess im still not sure if the timing ring is the same between the two engines .
With only one dealer saying that they are different between the two engines .
Click to expand...
So there are 2 types of crank seal assemblies (13 on the diagram, that include the timing ring)

030103171H
030103171L

In addition there are 3 crank sensors listed

030957147B AUA
030957147AB AUA, BBY Square
030957147S AUA, BBY Round

So it could be speculated that at some point the crank sensor was changed from square to round geometry for whatever reason; different supplier perhaps. So my hunch is that the two variants of crank seal assembly is all about accommodating the different crank sensor geometry’s but that the timing ring itself is most likely the same.
 
Azim said:
Im on the phone to a 3rd Audi dealer right now .
Will update very soon.

Update ....
They told me the spark plugs timing ring crank and camshaft sensor are the same .
Only the ignition side is different with the AUA having leads and the BBY having coil packs.

I guess im still not sure if the timing ring is the same between the two engines .
With only one dealer saying that they are different between the two engines .
Click to expand...
I'd go with the info in the old post above, as it's fact based
birtyA2 said:
So there are 2 types of crank seal assemblies (13 on the diagram, that include the timing ring)

030103171H
030103171L

In addition there are 3 crank sensors listed

030957147B AUA
030957147AB AUA, BBY Square
030957147S AUA, BBY Round

So it could be speculated that at some point the crank sensor was changed from square to round geometry for whatever reason; different supplier perhaps. So my hunch is that the two variants of crank seal assembly is all about accommodating the different crank sensor geometry’s but that the timing ring itself is most likely the same.
Click to expand...
My guess is that the original, AUA specific sensor, was first replaced, (with a BBY compatible part), along with the ring, on the run out of the AUA. The shape would have matched the machined housing in the AUA. Once the BBY became the norm, the sensor shape changed, to round, as round parts, and machined holes, are much easier, (and cheaper), than square ones.
.
It's likely, in my opinion, that the ring, in your AUA lower engine is the AUA specific part, but that the BBY compatible sensor was fitted as part of the BBY ECU loom.
Get a genuine AUA sensor, and it'll, (probably 🤞), run as it should.
Mac.
 
Unless the ECU is convinced that the engine is rotating, by the crankshaft sensor, it won't open the injectors, so, no fuel - no start.
Mac.
 
Azim said:
The engine was running of sorts .
Click to expand...
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.
 
Here's a write up on the AUA engine speed sender. There are two versions of the sender pictured, one square, and one round!
Mac.
Screenshot 2024-01-03 15.00.56.png
 

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