# 1.8t Audi A4 2003 quattro. Intermittent misfire, which is killing me



## moldovanos (Oct 1, 2009)

In 80% when car idles I have a misfire. Sometimes on cylinder 2, but mostly time on cylinder 4. When I drive its ok (watching live data with vag-com). Spark plugs, coils,injectors have been checked. Checked vacuum with vacuum gauge and its steady at 17.5 inch. Compression on cylinder 2 and 4 is 130 psi, on cylinder 1 and 3 150 psi.
Mechanic shops can not figure out the problem, dealership wants $700 just to start diagnostic, because it seems like a difficult problem. 
Here is my auto-scan results, please let me know what else can cause this misfire.
VCDS Version: Release 908.0
Data version: 20090911
Thursday,01,October,2009,15:03:25:20624
Chassis Type: 8E - Audi A4 B6/B7
Scan: 01 02 03 08 09 0F 11 15 16 17 18 36 37 45 46 55 56 57 65 67
69 75 76 77

VIN: WAULC68E93A332764 Mileage: 135280km/84059miles
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Address 01: Engine Labels: 06B-909-518-AMB.lbl
Part No SW: 8E0 909 518 AF HW: 8E0 909 018 A
Component: 1.8L R4/5VT G01 0003 
Coding: 0016701
Shop #: WSC 63351 000 00000
3 Faults Found:
16712 - Knock Sensor 1 (G61): Signal too High 
P0328 - 001 - Upper Limit Exceeded - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected 
P0300 - 001 - Upper Limit Exceeded - MIL ON
16688 - Cylinder 4: Misfire Detected 
P0304 - 001 - Upper Limit Exceeded - MIL ON
Readiness: 0000 0101
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Address 03: ABS Brakes Labels: 8E0-614-517.lbl
Part No: 8E0 614 517 H
Component: ABS/ESP allrad 2328 
Coding: 04275
Shop #: WSC 06435 
No fault code found.
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Address 08: Auto HVAC Labels: 8E0-820-043.lbl
Part No: 8E0 820 043 L
Component: A4 Klimaautomat 1116 
Coding: 00000
Shop #: WSC 63351 
1 Fault Found:
00474 - Control Module for Immobilizer 
49-00 - No Communications
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Address 09: Cent. Elect. Labels: 8E0-907-279-8E2.lbl
Part No: 8E0 907 279 E
Component: int. Lastmodul USA 0305 
Coding: 00003
Shop #: WSC 63351 
3 Faults Found:
01496 - Bulb for Fog-Lamps; Left (L22) 
57-00 - Electric Circuit Failure
01500 - Bulb for Fog-Lamps; Right (L23) 
57-00 - Electric Circuit Failure
00474 - Control Module for Immobilizer 
49-00 - No Communications
-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8E0-959-655-84.lbl
Part No: 8E0 959 655 C
Component: Airbag 8.4EP 2000 
Coding: 0010607
Shop #: WSC 63351 000 00000
2 Faults Found:
00654 - Seat Belt Tensioner Igniter; Driver Side (N153) 
001 - Upper Limit Exceeded - MIL ON
01217 - Side Airbag Igniter; Driver Side (N199) 
007 - Short to Ground - MIL ON
-------------------------------------------------------------------------------
Address 16: Steering wheel Labels: 8E0-953-549.lbl
Part No: 8E0 953 549 N
Component: Lenksáulenmodul 0308 
Coding: 00041
Shop #: WSC 63351 
1 Fault Found:
00474 - Control Module for Immobilizer 
49-00 - No Communications
-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8E0-920-9xx-8E2.lbl
Part No: 8E0 920 950 L
Component: KOMBI+WEGFAHRS. RB4 D36 
Coding: 03200
Shop #: WSC 00000 
WAULC68E93A332764 AUZ6Z0C0067887
1 Fault Found:
01176 - Key 
07-00 - Signal too Low
-------------------------------------------------------------------------------
Address 46: Central Conv. Labels: 8E0-959-433-MAX.lbl
Part No: 8E0 959 433 BB
Component: Komfortgerát T7B 1311 
Coding: 11848
Shop #: WSC 63351 
Part No: 8E1959801
Component: Tõrsteuer.FS BRM 0003 
Part No: 8E1959802E
Component: Tõrsteuer.BF BRM 0002 
Part No: 8E0959801A
Component: Tõrsteuer.HL BRM 0003 
Part No: 8E0959802A
Component: Tõrsteuer.HR BRM 0002 
1 Fault Found:
01366 - Opened Due to Crash Signal 
36-10 - Open Circuit - Intermittent
-------------------------------------------------------------------------------
Address 56: Radio Labels: 8E0-035-1xx-56.lbl
Part No: 8E0 035 195 F
Component: symphony II NP2 0051 
Coding: 01201
Shop #: WSC 03058 
No fault code found.
End ---------------------------------------------------------------------


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## moldovanos (Oct 1, 2009)

All stock, no mods


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## brk4euros514 (Aug 9, 2008)

*Re: (moldovanos)*

Well i had the same problem after i sucked up some moisture then weeks later got these mini misses in # 4 and 1. So i cleaned the maf with some spray from autozone or somewere.I was very skeptical at first using a can to fix my car sounds really screwy but if worked for me i have not misfires at all!


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## moldovanos (Oct 1, 2009)

*Re: (brk4euros514)*

Thanks for the reply. I already put a new MAF. Car ran great for a few hours and then started to misfire again. Measuring with vag-com shows that MAF is good.


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (moldovanos)*

Check out some of these links:
http://wiki.ross-tech.com/inde...00808
http://wiki.ross-tech.com/inde...00772
http://wiki.ross-tech.com/inde...00768
Also, did they replace the coils? Or are they OEM and the latest revision R?
Are the spark plugs new and OEM?
Did they do a running compression test? Or just cranking.
Are the intake manifold runners all the same temp. when it is running properly? Any significant temp. difference when it starts to misfire?
Is the breather system sealed up. (hoses under intake)
Is there intake vacuum at the valve cover when the oil cap is removed while running?
Last idea..Was the turbo checked for blow by or excessive shaft play?
How bad was this crashed? Front hit near timing belt?


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## moldovanos (Oct 1, 2009)

*Re: (Dana @ Ross-Tech)*

1)Spark plugs and coils are new and OEM. 
2)Only cranking compression test was done.
3)I am not sure about intake manifold runners, how do I check?
4)I will double check tomorrow if the breather system sealed up.
5)How to check intake vacuum at the valve cover? Just remove oil cap? What do I have to look for?
6) Turbo has not been checked. How to check it?
The car was crashed in front, did not look like engine was damaged. When front ends parts were being replaced (hood,bumper,radiator) mechanics did the timing belt job, just to do it, while engine was open. However they put it with one tooth off and had to re-do it. After that I noticed that upper pulley is wobbling, so we replaced that too. Then I checked timing with different shop and it appears to be ok and it does not throw any codes.
Thank a lot for answering. It gave me extra ideas what to check for.


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## Peter Badore (Jun 17, 2002)

*Re: (moldovanos)*

Slightly bents bent valves on the lower compression tested cylinders?
I would do a cylinder leak down test to check for bent valves.


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## moldovanos (Oct 1, 2009)

Can a knock sensor cause a misfire? Or the knock sensor error comes up because of misfire?


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## moldovanos (Oct 1, 2009)

So I unplugged the knock sensor and just left it hanging. Now I get the same misfire and knock sensor codes(see thread beginning), but "implausible signal" instead of "too high". 
16712 - Knock Sensor 1 (G61): Signal too low
P0327 - 02 - Signal too low
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - implausible signal 
16688 - Cylinder 4: Misfire Detected
P0304 - 001 - Implausible signal
How does computer read the knock sensor even if its not even connected? Is my computer bad or my knock sensor is bad? Or none of these and I still have to look for misfire somewhere else?


_Modified by moldovanos at 3:41 PM 10-2-2009_


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## vwemporium (May 27, 2002)

*Re: (moldovanos)*

I would bet you have a ground issue and the harness is damaged more then likely right at the valve cover.
This may in fact have damaged even the new coil packs.
It doesn't take long for internal damage to the logic of the power stage in the pack if the ground is insufficient.
If you swap packs from one to another cylinder does the fault move?
If it does how long before misfire starts?
Use Vag-Com to determine in block
01-08-014/015/016
Best,
Jack


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## moldovanos (Oct 1, 2009)

When I swap coils between cylinders misfire does not move, it is always at the same cylinders


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## vwemporium (May 27, 2002)

*Re: (moldovanos)*

There you go then.
Check the wires for those cylinders then maybe even run a new temp set to verify what im saying.
Its only 4 pulse + pwr wires back to the ECU and one ground that loops back to itself and the ecu and some other goodies.
Run at the very least an additional piggy back ground to that coil to test first right to the - neg. on battery.
There are two grounds per coil. Brown wires.
Best,
Jack


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (vwemporium)*

Sorry I haven't followed up with your questions. You have received some more excellent suggestions in the meanwhile. 
As Peter suggested_bent valves are definitely possible. The timing / cam. sprocket was hit in the collision to cause the bend. And the belt was installed incorrectly on a VVT engine! 
As Jack suggested_ground issue will cause such issues as well!
My answers to your numbered questions:
2)Only cranking compression test was done.__My shared concern with Peter. A running compression test can reveal real time internal engine issues. You would unplug the respective injector and ignition coil. Remove the spark plug and put the tester in that hole. Start the engine and watch the actual compression real time / and normal operating temp. This is sometimes more accurate than at cranking RPM.
A leak down test can also reveal such problems, but it will help diagnose where the leak is. Do not do that while it is running. 
3)I am not sure about intake manifold runners, how do I check?_Temp. gun
5)How to check intake vacuum at the valve cover? Just remove oil cap?_Yes It should blub blub...Not Suck
6) Turbo has not been checked. How to check it?_Remove the intercooler hoses and check for a ton of liquid oil. And remove the inlet hose at the turbo, grab the impeller shaft and see how much play there is in all directions. This is the least likely problem, do as a last resort.

Just to be clear, did the car ever run properly after the collision? Misfires and such..




_Modified by Dana @ Ross-Tech at 9:39 PM 10-2-2009_


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## moldovanos (Oct 1, 2009)

Nope, never ran properly after collision. Have an intermittent misfire for two months already.


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## Peter Badore (Jun 17, 2002)

*Re: (moldovanos) Crash damage*

I have seen so many mishaps and engine problems with Audi A4s and B5 Passats with collision
damage that we would need a lot of new threads to properly describre them all. The worse was an Audi Allroad that went through three 2.7l biturbo engines before it got fixed correctly.


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## moldovanos (Oct 1, 2009)

Thanks for the answers. After checking everything, we finally found the problem. It had 9 slightly bent valves.


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## Dana @ Ross-Tech (Sep 15, 2009)

*Re: (moldovanos)*

Thanks for the update. Sorry to hear that, Did you try the running compression test? Or did you find it with a conventional leak down test?


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## moldovanos (Oct 1, 2009)

Running compression test and when the car was hot compression was under 100 on two cylinders. I brought it to a shop, which took the head off and sent it out for checking. It costs $50 to check all the valves, its a special company,which specializes in that.


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## Peter Badore (Jun 17, 2002)

*Re: (moldovanos)*

Which Detroit area shop took the head off?


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## moldovanos (Oct 1, 2009)

*Re: (Peter Badore)*

Spectrum auto works in Oak park


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