AUA 1.4 misfire cylinder 2 - trim readings

Do I have SAI on an AUA?

EML is on a lot and blinks on misfire.

Having thought my replaced items I realised the EGR was a cheap unit so I just popped the Pierburg back on (one of the gaskets was made from an old coke can which I thought might have not helped,,,). All back together and the engine ran really sweet (1000rpm) until misfired again.

I tried to run an adaptation on the EGR but it fails.

P1404 basic setting not performed (wont allow me - tried to follow the VCDS http://wiki.ross-tech.com/wiki/index.php/Exhaust_Gas_Recirculation_(EGR)_Valve_Adaptation but fails)

POtentiometer for EGR P1439 error in basic setting.

Have disconnected battery and will see if that helps reset system to allow me to perfrom EGR adaptation
 
Make sure all parameters are met such a battery voltage, ambient temp etc, EGR very sensitive to this for adaption

J
 
tuizner said:
Do I have SAI on an AUA?

EML is on a lot and blinks on misfire.

Having thought my replaced items I realised the EGR was a cheap unit so I just popped the Pierburg back on (one of the gaskets was made from an old coke can which I thought might have not helped,,,). All back together and the engine ran really sweet (1000rpm) until misfired again.

I tried to run an adaptation on the EGR but it fails.

P1404 basic setting not performed (wont allow me - tried to follow the VCDS http://wiki.ross-tech.com/wiki/index.php/Exhaust_Gas_Recirculation_(EGR)_Valve_Adaptation but fails)

POtentiometer for EGR P1439 error in basic setting.

Have disconnected battery and will see if that helps reset system to allow me to perfrom EGR adaptation
Click to expand...
I don't think you'll successfully run any "Basic Settings" until all "Readiness" conditions are met.
If the SAI readiness bit is present, I'd think SAI was also present, but I have no detailed knowledge of 1.4 petrol engines, so can't be sure.
Mac.
 
tuizner said:
Original TEMIC unit (no cracks) replaced with an NGK coil and NGK plugs. Misfire occurs when engine is warm (3-5 minutes after start).
Click to expand...
that was exactly the symptom on ours when I finally homed in on the coil. No misfires when you started, but on a reasonably warm day at the idle, 3-5 minutes in you would start hearing the idle get a bit lumpy and could start seeing the misfire count kicking off before the cylinder was switched off automatically and it started running on 3.
 
Robin_Cox said:
that was exactly the symptom on ours when I finally homed in on the coil. No misfires when you started, but on a reasonably warm day at the idle, 3-5 minutes in you would start hearing the idle get a bit lumpy and could start seeing the misfire count kicking off before the cylinder was switched off automatically and it started running on 3.
Click to expand...
Thanks Robin. Coincidentally I just finished reading your thread.

New NGK coil hasn't solved mine. I have new Bosch leads on the way.
Robin_Cox said:
that was exactly the symptom on ours when I finally homed in on the coil. No misfires when you started, but on a reasonably warm day at the idle, 3-5 minutes in you would start hearing the idle get a bit lumpy and could start seeing the misfire count kicking off before the cylinder was switched off automatically and it started running on 3.
Click to expand...
Thanks Robin. Coincidentally I just finished reading your thread. You left us hanging though back in November 22 with an EPC light...

New NGK coil hasn't solved mine. I have new Bosch leads on the way and I will put in a new thermostat as mine stays at 60 for ages.
 
tuizner said:
Thanks Robin. Coincidentally I just finished reading your thread.

New NGK coil hasn't solved mine. I have new Bosch leads on the way.

Thanks Robin. Coincidentally I just finished reading your thread. You left us hanging though back in November 22 with an EPC light...

New NGK coil hasn't solved mine. I have new Bosch leads on the way and I will put in a new thermostat as mine stays at 60 for ages.
Click to expand...
Thermostat / temp sensor are the only things on our AUA that have never given us any issue (incredibly given how many other things needed to be replaced due to years of neglect before our tenure!) - it always warms up quickly and reliably - if an AUA is slow to warm up I suspect your hunch is correct. Probably jinxed it now but hey ho!...

As I've had a few threads on this car that I've tried to keep updated I've lost track of which one ended with the EPC light, but looking at the date, it would suggest that was when I decided it was time to confront the "lambda sensor earth / open to ground sporadic" issue and fitted an authentic NTK/NGK lambda sensor. This has resulted in significant improvements in running and overall fuel efficiency to the point that I've not had to do anything else in the past 7 months, although I'm contemplating replacing the alternator with a 110A one as in cold temperatures I think the original allows voltage to dip a bit which can cause sudden dashboard Christmas-tree decoration events if ECUs get unhappy with the voltage drop. That's reminded me, I need to order a new alternator belt - thank you!

Keep on plugging away with your car - you'll get to the bottom of it eventually and it is very rewarding when you see the fruits of your efforts running sweetly! Best, Robin
 
still no joy - misfire on 2.
  • removed and cleaned earth strap [cannot get to the starter motor but looks clean]
  • changed injector wiring 2/3 [can just about do it at a stretch] - doesnt affect - only cylinder 2 therefore cannot we injector or wiring to injector.
  • good look around for leaks - smoke test looks fine [air side of TB and ACF / evap]
  • vcds below.
  • STFT [black line] is moving a lot
  • LTFTs for both additive and mult are at zero and dont move [block 032]
  • upon misfire - all data does not move apart from the 033 bank 1 voltage.


1690127347894.png
 
tuizner said:
still no joy - misfire on 2.
  • removed and cleaned earth strap [cannot get to the starter motor but looks clean]
  • changed injector wiring 2/3 [can just about do it at a stretch] - doesnt affect - only cylinder 2 therefore cannot we injector or wiring to injector.
  • good look around for leaks - smoke test looks fine [air side of TB and ACF / evap]
  • vcds below.
  • STFT [black line] is moving a lot
  • LTFTs for both additive and mult are at zero and dont move [block 032]
  • upon misfire - all data does not move apart from the 033 bank 1 voltage.


View attachment 110925
Click to expand...
Full VCDS engine scan and readiness are needed, to see if anything has changed.
I think you may be focusing too much on fuelling data. I'd be guided by the engine scan results, they may be the cause of the fuelling data you're seeing. The lambda sensor is the primary factor controlling fuelling.
Mac.
 
Cannot perform a full readiness as the misfire happens before I can do the evap test (asks for idle to perform the test but misfires straight away when warm). I will try and do the readiness on the others though.
 
Hi
Can we just confirm that your planned set of Bosch ignition leads are now on?

To confirm:
New Bosch ignition leads
New spark plugs
New NGK ignition coil
Original Pierburg EGR back in but not adapted
Throttle body cleaned (did it adapt ok)
Compression test OK, what were the values

And the symptoms; lumpy idle after a few mins on warm up with rich smell to exhaust. This is born out by VCDS high misfire count on cylinder 2 with misfire starting a bit on cylinder 1 as it warms.

I agree with Mac that the the pre cat lambda does the heavy lifting on fuel mix. To my amateur mind I would expect misfires to be showing across the cylinders if the fuel mix was being miscalculated due to incorrect signal from the sensor?

I guess the next step would be for me to try and replicate the readings on my AUA so your results can be compared with what I get. Sadly I only have an in registered copy of VCDS Lite, but I will see what I can do with with XTool 401

J
 
PlasticMac said:
Full VCDS engine scan and readiness are needed, to see if anything has changed.
I think you may be focusing too much on fuelling data. I'd be guided by the engine scan results, they may be the cause of the fuelling data you're seeing. The lambda sensor is the primary factor controlling fuelling.
Mac.
Click to expand...

all ready apart from evap which will not test as misfires before test starts. does anyone know what happens in this test? i noted the first column would rise to 30% then go to zero and repeat but could not complete before misfire - wonder if something in the evap is causing the issue? sort of makes sense in that it only misfires at idle and warm?

readiness and 2 full scans below - one before a drive and one just after - note many of the addresses could not communicate after the drive....




VIN: WAUZZZ8ZZ1N006856 License Plate:
Readiness Status: 0000 0100
Exhaust Gas Recirculation: Passed
Oxygen Sensor Heating: Passed
Oxygen Sensor(s): Passed
Air Conditioning: Passed
Secondary Air Injection: Passed
Evaporative Emissions: Failed or Incomplete
Catalyst Heating: Passed
Catalytic Converter(s): Passed



scan

Chassis Type: 8Z (8Z - Audi A2 (2000 > 2005))
Scan: 01 02 03 08 15 16 17 18 37 45 46 56 57 75 76 77

VIN: WAUZZZ8ZZ1N006856
-------------------------------------------------------------------------------
Address 01: Engine Labels: 036-906-034-APE.lbl
Part No: 036 906 034 Q
Component: MARELLI 4LV 3415
Coding: 00051
Shop #: WSC 02154
VCID: 2019F271D3DE0E9A2FB-4B3C
WAUZZZ8ZZ1N006856 AUZ7Z0Y1502671

No fault code found.
Readiness: 1110 0101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8Z0-907-379-MK20.lbl
Part No: 8Z0 907 379 A
Component: ESP 20 CAN V008
Coding: 10758
Shop #: WSC 02154
VCID: 46D544E911BA00AA757-4B1E

1 Fault Found:
01314 - Engine Control Module
79-10 - Please Check Fault Codes - Intermittent

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: None
Part No: 8Z0 820 043
Component: A2-KLIMAVOLLAUTOMAT 0406
VCID: 73B3CD3D32A8C502029-258E

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8Z0-959-655.lbl
Part No: 8Z0 959 655 E
Component: Airbag Front+Seite 3004
Coding: 00102
Shop #: WSC 02154
VCID: 4EC57CC9F9CAC8EACD7-5160

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Z0-920-xxx-17.lbl
Part No: 8Z0 920 950 D
Component: W1-KOMBIINSTR. VDO D12
Coding: 05442
Shop #: WSC 00258
VCID: 3FDB510D4E605162361-5160
WAUZZZ8ZZ1N006856 AUZ7Z0Y1502671

1 Fault Found:
01309 - Power Steering Control Module (J500)
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: None
Part No: 8Z0 951 177 A
Component: Innenraumueberw. D01
Coding: 00001
Shop #: WSC 00986
VCID: 41DF57F538942792405-513C

1 Fault Found:
01463 - Alarm triggered by Sensor for anti-theft alarm System
43-00 - Closed

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels:. 8Z0-959-433.lbl
Part No: 8Z0 959 433 E
Component: Komfortgerát T19 03B1
Coding: 06890
Shop #: WSC 00778
VCID: 48C94AD11BAE16DA87B-4B00

Subsystem 1 - Part No: 8Z2959802
Component: Tõrsteuer.FS BRM 0001

Component: Tõrsteuer.BF BRM 0003

7 Faults Found:
01134 - Alarm Horn (H12)
49-00 - No Communications
01370 - Alarm triggered by Interior Monitoring
35-00 - -
01374 - Alarm triggered by Terminal 15
35-00 - -
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
01559 - Drivers Door
60-10 - Won't Safe - Intermittent
01560 - Passenger Door
61-00 - Won't De-Safe
01561 - Rear left door
59-00 - Can't Unlock

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8D0-035-1xx-56.lbl
Part No: 4B0 035 186 E
Component: Radio 0001
Coding: 00205
Shop #: WSC 02325
VCID: 221DF879DDD21C8A39F-4B00

1 Fault Found:
00854 - Radio Display Output in dash Panel insert
49-00 - No Communications

End----(Elapsed Time: 03:33, VBatt start/end: 12.0V/12.0V. VIgn 11.9V)-----
Sunday,23,July,2023,18:37:03:57049
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64) HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com






Sunday,23,July,2023,19:24:11:57049
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64) HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
chassis Type: 8Z - Audi A2 (2000 > 2005)
Scan: 01 02 03 08 15 16 17 18 37 45 46 56 57 75 76 77
-------------------------------------------------------------------------------
Address 01: Engine Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 15: Airbags Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 17: Instruments Labels:
VCID: 55F793A5DC0CBB320CD-5160
Note: Excessive Comm Errors
-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 46: Central Conv. Labels:. 8Z0-959-433.lbl
Part No: 8Z0 959 433 E
Component: Komfortgerát T19 03B1
Coding: 06890
Shop #: WSC 00778
VCID: 48C94AD11BAE16DA87B-4B00

Subsystem 1 - Part No: 8Z0959433E
Component: Komfortgerát T19 03B1

Component: Z2959802 Tõrsteuer

7 Faults Found:
01134 - Alarm Horn (H12)
49-00 - No Communications
01370 - Alarm triggered by Interior Monitoring
35-00 - -
01374 - Alarm triggered by Terminal 15
35-00 - -
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
01559 - Drivers Door
60-10 - Won't Safe - Intermittent
01560 - Passenger Door
61-00 - Won't De-Safe
01561 - Rear left door
59-00 - Can't Unlock
-------------------------------------------------------------------------------
Address 56: Radio Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
End----------(Elapsed Time: 04:37, VBatt start/end: 12.6V/12.3V)-----------
 
birtyA2 said:
Hi
Can we just confirm that your planned set of Bosch ignition leads are now on?

To confirm:
New Bosch ignition leads
New spark plugs
New NGK ignition coil
Original Pierburg EGR back in but not adapted
Throttle body cleaned (did it adapt ok)
Compression test OK, what were the values

And the symptoms; lumpy idle after a few mins on warm up with rich smell to exhaust. This is born out by VCDS high misfire count on cylinder 2 with misfire starting a bit on cylinder 1 as it warms.

I agree with Mac that the the pre cat lambda does the heavy lifting on fuel mix. To my amateur mind I would expect misfires to be showing across the cylinders if the fuel mix was being miscalculated due to incorrect signal from the sensor?

I guess the next step would be for me to try and replicate the readings on my AUA so your results can be compared with what I get. Sadly I only have an in registered copy of VCDS Lite, but I will see what I can do with with XTool 401

J
Click to expand...
still waiting on the bosch leads - should be tomorrow.
but:
swapped exisiting leads over
new ngk plus
new ngk coil
pierburg egr back on - cant recall if i adapted it...
TB cleaned and adapted
compression on all at close to 15 bar (draper tester)
leak down on all cylinders - all around 20% (sealey)
new evap solenoid (bosch)
cleaned earth strap
replaced injectors
swapped injector connectors 2 / 3 [and back]
smoke tested for leaks
new alternator
 
PlasticMac said:
Idle speculation, just wondering if the early single coil pack cars could be converted to the later separate variety. The schematic only shows the later.
Mac.
Click to expand...
Found this on the German Wiki

ignition coils​

The AUA engine has a dual ignition coil, each serving two cylinders. As a result, the engine control unit only has two lines that go to the dual ignition coil. A special feature of the AUA engine is that 2 spark plugs ignite at the same time. The other cylinder is in the exhaust stroke. This means that it is ignited twice as often as is actually required.

The BBY engine has 4 ignition coils that are housed directly in the spark plug connector. 4 lines lead from the engine control unit to the ignition coils. There are therefore no longer double ignitions as in the AUA.


Never knew that

J
 
tuizner said:
all ready apart from evap which will not test as misfires before test starts. does anyone know what happens in this test? i noted the first column would rise to 30% then go to zero and repeat but could not complete before misfire - wonder if something in the evap is causing the issue? sort of makes sense in that it only misfires at idle and warm?

readiness and 2 full scans below - one before a drive and one just after - note many of the addresses could not communicate after the drive....




VIN: WAUZZZ8ZZ1N006856 License Plate:
Readiness Status: 0000 0100
Exhaust Gas Recirculation: Passed
Oxygen Sensor Heating: Passed
Oxygen Sensor(s): Passed
Air Conditioning: Passed
Secondary Air Injection: Passed
Evaporative Emissions: Failed or Incomplete
Catalyst Heating: Passed
Catalytic Converter(s): Passed



scan

Chassis Type: 8Z (8Z - Audi A2 (2000 > 2005))
Scan: 01 02 03 08 15 16 17 18 37 45 46 56 57 75 76 77

VIN: WAUZZZ8ZZ1N006856
-------------------------------------------------------------------------------
Address 01: Engine Labels: 036-906-034-APE.lbl
Part No: 036 906 034 Q
Component: MARELLI 4LV 3415
Coding: 00051
Shop #: WSC 02154
VCID: 2019F271D3DE0E9A2FB-4B3C
WAUZZZ8ZZ1N006856 AUZ7Z0Y1502671

No fault code found.
Readiness: 1110 0101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8Z0-907-379-MK20.lbl
Part No: 8Z0 907 379 A
Component: ESP 20 CAN V008
Coding: 10758
Shop #: WSC 02154
VCID: 46D544E911BA00AA757-4B1E

1 Fault Found:
01314 - Engine Control Module
79-10 - Please Check Fault Codes - Intermittent

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: None
Part No: 8Z0 820 043
Component: A2-KLIMAVOLLAUTOMAT 0406
VCID: 73B3CD3D32A8C502029-258E

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8Z0-959-655.lbl
Part No: 8Z0 959 655 E
Component: Airbag Front+Seite 3004
Coding: 00102
Shop #: WSC 02154
VCID: 4EC57CC9F9CAC8EACD7-5160

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Z0-920-xxx-17.lbl
Part No: 8Z0 920 950 D
Component: W1-KOMBIINSTR. VDO D12
Coding: 05442
Shop #: WSC 00258
VCID: 3FDB510D4E605162361-5160
WAUZZZ8ZZ1N006856 AUZ7Z0Y1502671

1 Fault Found:
01309 - Power Steering Control Module (J500)
49-10 - No Communications - Intermittent

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: None
Part No: 8Z0 951 177 A
Component: Innenraumueberw. D01
Coding: 00001
Shop #: WSC 00986
VCID: 41DF57F538942792405-513C

1 Fault Found:
01463 - Alarm triggered by Sensor for anti-theft alarm System
43-00 - Closed

-------------------------------------------------------------------------------
Address 46: Central Conv. Labels:. 8Z0-959-433.lbl
Part No: 8Z0 959 433 E
Component: Komfortgerát T19 03B1
Coding: 06890
Shop #: WSC 00778
VCID: 48C94AD11BAE16DA87B-4B00

Subsystem 1 - Part No: 8Z2959802
Component: Tõrsteuer.FS BRM 0001

Component: Tõrsteuer.BF BRM 0003

7 Faults Found:
01134 - Alarm Horn (H12)
49-00 - No Communications
01370 - Alarm triggered by Interior Monitoring
35-00 - -
01374 - Alarm triggered by Terminal 15
35-00 - -
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
01559 - Drivers Door
60-10 - Won't Safe - Intermittent
01560 - Passenger Door
61-00 - Won't De-Safe
01561 - Rear left door
59-00 - Can't Unlock

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8D0-035-1xx-56.lbl
Part No: 4B0 035 186 E
Component: Radio 0001
Coding: 00205
Shop #: WSC 02325
VCID: 221DF879DDD21C8A39F-4B00

1 Fault Found:
00854 - Radio Display Output in dash Panel insert
49-00 - No Communications

End----(Elapsed Time: 03:33, VBatt start/end: 12.0V/12.0V. VIgn 11.9V)-----
Sunday,23,July,2023,18:37:03:57049
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64) HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com






Sunday,23,July,2023,19:24:11:57049
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 11 x64
VCDS Version: 23.3.1.0 (x64) HEX-V2 CB: 0.4631.4
Data version: 20230421 DS346.2
www.Ross-Tech.com
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
chassis Type: 8Z - Audi A2 (2000 > 2005)
Scan: 01 02 03 08 15 16 17 18 37 45 46 56 57 75 76 77
-------------------------------------------------------------------------------
Address 01: Engine Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 15: Airbags Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 17: Instruments Labels:
VCID: 55F793A5DC0CBB320CD-5160
Note: Excessive Comm Errors
-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
-------------------------------------------------------------------------------
Address 46: Central Conv. Labels:. 8Z0-959-433.lbl
Part No: 8Z0 959 433 E
Component: Komfortgerát T19 03B1
Coding: 06890
Shop #: WSC 00778
VCID: 48C94AD11BAE16DA87B-4B00

Subsystem 1 - Part No: 8Z0959433E
Component: Komfortgerát T19 03B1

Component: Z2959802 Tõrsteuer

7 Faults Found:
01134 - Alarm Horn (H12)
49-00 - No Communications
01370 - Alarm triggered by Interior Monitoring
35-00 - -
01374 - Alarm triggered by Terminal 15
35-00 - -
01371 - Alarm triggered by Door Contact Switch; Driver's Side
35-00 - -
01559 - Drivers Door
60-10 - Won't Safe - Intermittent
01560 - Passenger Door
61-00 - Won't De-Safe
01561 - Rear left door
59-00 - Can't Unlock
-------------------------------------------------------------------------------
Address 56: Radio Labels:
VCID: 55F793A5DC0CBB320CD-FFFE
End----------(Elapsed Time: 04:37, VBatt start/end: 12.6V/12.3V)-----------
Click to expand...
Hmm...
Must admit, I can't understand the scans.
How can there be no engine faults, when it's got such an, (apparently), high miss fire count?
The second scan doesn't seem to have scanned anything other than the CCU.
I seen comments elsewhere, that running VCDS on a virtual machine is suspect.
(Possibly to prevent running it being installed on several pcs, each with the same virtual machine).
Mac
 
birtyA2 said:
Found this on the German Wiki

ignition coils​

The AUA engine has a dual ignition coil, each serving two cylinders. As a result, the engine control unit only has two lines that go to the dual ignition coil. A special feature of the AUA engine is that 2 spark plugs ignite at the same time. The other cylinder is in the exhaust stroke. This means that it is ignited twice as often as is actually required.

The BBY engine has 4 ignition coils that are housed directly in the spark plug connector. 4 lines lead from the engine control unit to the ignition coils. There are therefore no longer double ignitions as in the AUA.


Never knew that

J
Click to expand...
That's very odd, and I'd really like to know the logic behind it.
But it does means a misfire on one cylinder could be down to a problem on it's twin.
It must also have a unique ECU.
Mac.
 
new bosch leads = no change.

one thing i havent mentioned is that as the engine warms up (and gets rougher idling) there appears a rattling noise from the tunnel - as though something is vibrating against the body [does not appear to be the exhaust]. does not appear on a cold start - only after a couple of minutes of warming and the revs starting to come down from 1000 towards the 725 at warm idle. could this be the evap system i wonder? it cannot perform an evap readiness test and so i wonder if there is a leak or block somewhere from the tank... will look to see if anything else can help on vcds here.

will give it a couple more days then send off to a garage.
 
I would place a small bet on the ignition coil. It is very important to have the right one if it has been recently replaced. This is a road that I have travelled and in my case I found the tiniest cracks in the casing of the coil underneath where they are invisible. I have also fitted the expensive Denso plugs and run on Tesco 99 octane.

Best of luck,
 
simon martyn said:
I would place a small bet on the ignition coil. It is very important to have the right one if it has been recently replaced. This is a road that I have travelled and in my case I found the tiniest cracks in the casing of the coil underneath where they are invisible. I have also fitted the expensive Denso plugs and run on Tesco 99 octane.

Best of luck,
Click to expand...
changing the original coil for an NGK unit did not alter things. original coil also looked fine with no cracks. i suppose it "could" be a dud new coil but then poor ignition issues would happen from scratch and this only starts when warm and at idle only. i think time for an auto electrician / diagnostics man to get involved...
 
You can check the evap system here:

Group 070, Emission Reducing
Block 1,Opening Angle,of TVV. (I'd think TVV = Tank Vent Valve). It may be that this valve is not opening, so no EVAP. This should should tell you.
Block 2,Lambda Controller Diagnostic Value
Block 3,Intake manifold pressure, between: 240...420 mbar
Block 4,Result Evap. Emissions Display Range: Test ON/Test OFF/TEV OK/TEV not OK

Note, that Lambda sensor again.
Mac.
 
PlasticMac said:
You can check the evap system here:

Group 070, Emission Reducing
Block 1,Opening Angle,of TVV. (I'd think TVV = Tank Vent Valve). It may be that this valve is not opening, so no EVAP. This should should tell you.
Block 2,Lambda Controller Diagnostic Value
Block 3,Intake manifold pressure, between: 240...420 mbar
Block 4,Result Evap. Emissions Display Range: Test ON/Test OFF/TEV OK/TEV not OK

Note, that Lambda sensor again.
Mac.
Click to expand...
Might also be worth checking the fuel filler cap is in good condition

J
 
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