abwc

So I start the car yesterday afternoon, late in the day, and the check engine light is flashing and the engine is running rough, like it's misfiring.

So I shut it down and take the M3 instead.

After dinner, I jack into the car with VAG to see what going on.

In ECU 1, I see this:

Thursday,14,December,2006,19:53:09
VAG-COM Version: Release 607.3-UD

Control Module Part Number: 8E1 910 560 A
Component and/or Version: 4.2L V8/4V FSI ?0040
Software Coding: 01040009180F0160
Work Shop Code: WSC 20209


006435 - Please Check DTC Memory of ECU Number 2
P1923 - 008 - Implausible Signal
Freeze Frame:
Fault Status: 01101000
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 0 /min
Load: 0.0 %
Speed: 0.0 km/h
Temperature: 15.0°C
Temperature: 15.0°C
Absolute Pres.: 820.0 mbar
Voltage: 11.811 V


Readiness: 0000 0000
---------------------------------------------------------------------------

So I go check ECU 2, and I see this:

---------------------------------------------------------------------------

Thursday,14,December,2006,19:55:35
VAG-COM Version: Release 607.3-UD

Control Module Part Number: 8E1 910 560 A
Component and/or Version: 4.2L V8/4V FSI ?0040
Software Coding: 01040009180F0160
Work Shop Code: WSC 20209


000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 1345 /min
Load: 40.0 %
Speed: 0.0 km/h
Temperature: 14.0°C
Temperature: 15.0°C
Absolute Pres.: 830.0 mbar
Voltage: 13.208 V

000773 - Cylinder 5: Misfire Detected
P0305 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 1345 /min
Load: 40.0 %
Speed: 0.0 km/h
Temperature: 14.0°C
Temperature: 15.0°C
Absolute Pres.: 830.0 mbar
Voltage: 13.208 V

000769 - Cylinder 1: Misfire Detected
P0301 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 1345 /min
Load: 40.0 %
Speed: 0.0 km/h
Temperature: 14.0°C
Temperature: 15.0°C
Absolute Pres.: 830.0 mbar
Voltage: 13.208 V

000771 - Cylinder 3: Misfire Detected
P0303 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 1340 /min
Load: 39.6 %
Speed: 0.0 km/h
Temperature: 18.0°C
Temperature: 15.0°C
Absolute Pres.: 830.0 mbar
Voltage: 13.208 V

000770 - Cylinder 2: Misfire Detected
P0302 - 001 - Upper Limit Exceeded
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Mileage: 14031 km
Time Indication: 0

Freeze Frame:
RPM: 1340 /min
Load: 39.6 %
Speed: 0.0 km/h
Temperature: 18.0°C
Temperature: 15.0°C
Absolute Pres.: 830.0 mbar
Voltage: 13.208 V

---------------------------------------------------------------------------

Hmmm, interesting. That's what I suspected.

So, I clear the fault codes, and then I set up a logging session on:

Engine Speed
Misfire: Cylinder 1
Misfire: Cylinder 2
Misfire: Cylinder 3
Misfire: Cylinder 4
Misfire: Cylinder 5
Misfire: Cylinder 6
Misfire: Cylinder 7
Misfire: Cylinder 8
Rail Pressure

... and then I start the car.

No blinking check engine light, no misfire.

I test drive the car, all the way through warm-up, and then through a series of rpms and throttle positions.

I find that misfires occur all the time, typically when the engine undergoes a big change, such as when load changes suddenly, such as when accelerating from a stop, or when lifting off the throttle. Various cylinders misfire here and there, but you can't feel it or hear it, except in the lift-off condition, where ignition timing is retarding quickly and you hear that exhaust burble. These kinds of misfire are detected, but the counters are reset after a few seconds, so they don't generate Fault Codes.

I get back to the house and I check the fault codes again.

Nothing, no fault codes found.

So, I am at a loss to explain why my car acted up yesterday afternoon, but it was cool to be able to check it out and snapshot the logs of the faults for later reference...

HiRev

Sounded just fine when you rumbled by the house last night.

abwc

Yeah, weird...now we know why the Techs can never replicate the problem

Evil Buddha

were shipped with shipping spark plugs. The dealer should have swapped them out. Some owners were having issue with that. Probably not the solution but if it were my RS I would check it out.

abwc

8700 miles... problem appears to have gone away by itself... weird.

daveak05

Your sprk plug idea...it's a good starting point, based on multiple cyl misfires. Either that or the ECU doesn't want to keep the engine on : )

daveak05

quit wasting our time here! : ) : )

Oh, and I would NOT assume that problem has gone away by itself.

daveak05

Yes, I benefit greatly here, can't you tell?

HiRev

not really.

daveak05

look, I don't know you, but if you want to open the ball with me that way, then whatever. It probably wouldn't matter to either one of us anyway.