# Multiply / random Misfire Detected on cylinder 1, 2, 3.



## Realization (Jan 3, 2007)

*Audi A6 2.8L Quattro 1999 (C5) - ECM/fuel inject. wire problem*

Audi A6 2.8L Quattro 1999 (C5).
Does anyone know if the (fuel injector) wiring harness coming from the ECM and the ECM it self is the exact same parts as on a Passat V6 1999? 
Audi A6 ECM Part#: 4D0 907 551 AH
I see them on eBay for $100, but I am not if a used ecm will plugin without any reprogramming 


_Modified by Realization at 9:45 AM 1-22-2007_


----------



## bi-turbo'd (Sep 18, 2006)

*Re: Multiply / random Misfire Detected on cylinder 1, 2, 3. (Realization)*

is that what they "sold" you. That seems like alot more work than necessary. I work at a shop and its usually little things causing a P0300 like some water in the plug socket, or in the coil. sometimes a fouled plug. I've never done that much though.


----------



## formulagigi (Sep 20, 2006)

*Re: Multiply / random Misfire Detected on cylinder 1, 2, 3. (bi-turbo'd)*

coil packs are the culprits on those codes a majority of the time although it could be plug or wire related.
Are you sure your coil paks are not dead? They are know to go on our cars. Just had three go within 2 weeks.


----------



## Realization (Jan 3, 2007)

*Follow up: Multiply / random Misfire Detected on cylinder 1, 2, 3.*

I did replace the coil, but no improvement. When I took it to the Audi dealer to a diagnostic they only gave me the first pages of the report which indicated Multiply / random Misfire Detected on cylinder 1, 2, 3. P0301/P0302/P0303…. but they also told me that the car at some point had “low fuel”. Could that be a defective fuel filter? Rumors say they don’t always last the lifetime of the car.
I would like to go back to Audi and ask the full report since I already paid $115 for it and didn’t get the full report. However I think they wont put the car on the system again for free............


----------



## 2001a62.7t (Feb 28, 2005)

have a compression test done on the engine.... i had random misfires on my car it ended up being a faulty valve seat... the way the computer works if a cylinder is loosing compresion it will cause others to misfire at random....hope this helps,and good luck


_Modified by 2001a62.7t at 2:03 AM 1-13-2007_


----------



## Realization (Jan 3, 2007)

*Re: (2001a62.7t)*

I will try to get a compression tes asap.
Codes detected by Audi Diagnostic computer: P1300 = low fuel sporadic, Random/multiply misfire P0300, P0301, P0302, P0303
Any advise please?
I already did the following
1. Replaced all 6 plugs with prescribed NGK plugs (old plugs looked ok)
2. Replaced all 6 spark wires (some wires where broken)
3. Replaced ignition coil
4. Switched fuel injectors from one side to the other
5. Replaced O-rings on fuel injectors
6. Replaced all vacuum hoses
7. Tested for vacuum leaks (no leaks)
8. LT & RT Variable Valve timing Actuator seals, Lt & Rt Valve cover gaskets, timing belt, crank seal, cam seal. replaced in 2004
Misfire continues after resetting/clearing codes and on same side.
Codes return after sometimes 52 miles and sometimes as little as 4 miles. When driving over 65/mph the car shakes. The temperature indicator is going between min and medium level, even after hrs of driving.
Bentley mentions"POWER OUTPUT STAGE" in connection with ignition coils. What 
is the "output stage"??
Could it be an O2 sensor/knock sensor/camshaft position sensor/a gasket/ fuel filter?
Is there anything major inside the engine that account for the random 
misfire on only one side?
Please help


----------



## 2001a62.7t (Feb 28, 2005)

'POWER OUTPUT STAGE'= this may refer to but i'm not sure if it is....... I'm not sure on the 2.8 but, on the 2.7t there are 2 "chips" that sit atop the airbox. there are 2 of them one for each bank. best of luck to ya.


----------



## 7even18 (Dec 20, 2006)

*Re: (Realization)*

I'm currently having the exact same problems with my 1.8T motor. 
Also going through the process of elimination. 
The only difference is that, after I replaced the coil packs, the problem only occurs when the motor is cold. After warming up, rough idle disappears, not completely, but runs more smoothly?
Was there any difference after you replaced the injectors?
I've already replaced all obvisous parts.


----------



## Realization (Jan 3, 2007)

*Re: (7even18)*

There was no change when moving the fuel injectors from one cylinder to the other. If you haven't tried that, this is a way to either eliminate the fuel injectors or find the defect one.
My car is a 2.8 which means the cylinder setup is devided on two bays
The problem with my car is in the voltage provided from the ECM to the fuel injectors is wrong on bay one 1. I am currently looking for someone who knows what the correct voltage level is supposed to be.
This will tell me if its a wire or the ecm.


----------



## 2001a62.7t (Feb 28, 2005)

i think these are what the bentley refers to 










_Modified by 2001a62.7t at 11:08 PM 1-16-2007_


----------



## Realization (Jan 3, 2007)

*Re: (2001a62.7t)*

Yes that is correct. Thank you. 
If you have access to the Bentley repair book. Can you tell me how to measure if the voltage input to the fuel injectors is correct?
Audi A6 2.8L 1999 (AHA-engine)


----------



## GLS-S4 (Jun 6, 2005)

*Re: (Realization)*

Buy Bentley, it's the best specialty tool you'll ever own... along with VAG-COM http://****************.com/smile/emthup.gif 
In this case, Bentley refers to proprietary VAG tools for testing voltages to Fuel Injectors using indicator lights, but no voltages are given.
IIRC Fuel Injector voltage is measured between the two connector pins and are 12V, fuel pump relay needs to be energized to read an injector value. Engine may need to be turning to trigger. Fuel Injector internal resistance is approx 15 ohms.
Don't take above as the gospel and others may have better ideas.


_Modified by GLS-S4 at 2:04 PM 1/17/2007_


----------



## Realization (Jan 3, 2007)

*Re: (2001a62.7t)*

In regards to my misfire problem on Cylinder 1, 2, 3. Does anyone know where the Power Output Stage is on an Audi A6 2.8L 1999 and how do I check if it is defective?
Please help...this problem is driving me


----------



## formulagigi (Sep 20, 2006)

*Re: (Realization)*

Is it on top of the air box on yours? 2 of them...


----------



## 2001a62.7t (Feb 28, 2005)

i know on the a6 2.7t and the s4 2.7t those are mounted on top of a heat sink plate on the air box


----------



## 2001a62.7t (Feb 28, 2005)

any news?????????? did you find the cause of the problem


----------



## Realization (Jan 3, 2007)

*Re: (2001a62.7t)*

Haven't had a chance to look at the car again. I got some good directions from another person in here that I will try out. I will let you know what the outcome is.


----------

