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Misfire! Help


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10 replies to this topic

#1 romandec

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Posted June 23, 2009 - 01:21 PM

I have a Cayenne Turbo 2004. The cel came on. I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct. They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


Edited by Loren, June 23, 2009 - 02:02 PM.
Removed ALL CAPS - please do not post in ALL CAPS

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#2 Twincharger

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Posted June 23, 2009 - 01:39 PM

I have a Cayenne Turbo 2004. The cel came on.
I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct.
They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


Please use lower case - so much easier to read.

Also, please post codes from Durametric - I have just gone through the same problem on my Turbo and resolved it.
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#3 mudman2

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Posted June 23, 2009 - 02:16 PM

Plugs were damaged by the bad coils


I have a Cayenne Turbo 2004. The cel came on.
I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct.
They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


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#4 wvicary

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Posted June 23, 2009 - 05:22 PM

The plug could be damaged. Swap it with another cylinder and see if the fault follows the spark plug.


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#5 romandec

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Posted June 30, 2009 - 10:51 AM

I took the car out yesterday for a test drive and used after the Durametric software to see the memorized error codes:

MOTRONIC 7.1

P0300
Random Multiple Cylinder Misfire
Detected
present

P0303
Cylinder 3 Misfire Detected
present

GATEWAY

457 Vehicle electric system control
module (CAN comfort)
no signal/communicaton

Electric system
Current
907 Load management operat. on vehicle
electric. system/DME control module
present

When I monitor live all 8 cylinders for misfire monitoring while engine running idle I get:
Misfire counter cylinder 7.........10 times (in about 1 minute time)

I have scheduled the spark plugs change in 10 days (not possible before) in another town, do you think there may be something else that I need to consider might need to get fixed?

Thank you all in advance for your great help.

Romandec



I have a Cayenne Turbo 2004. The cel came on.
I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct.
They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


Please use lower case - so much easier to read.

Also, please post codes from Durametric - I have just gone through the same problem on my Turbo and resolved it.

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#6 Loren

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Posted June 30, 2009 - 12:06 PM

I took the car out yesterday for a test drive and used after the Durametric software to see the memorized error codes:

MOTRONIC 7.1

P0300
Random Multiple Cylinder Misfire
Detected
present

P0303
Cylinder 3 Misfire Detected
present

GATEWAY

457 Vehicle electric system control
module (CAN comfort)
no signal/communicaton

Electric system
Current
907 Load management operat. on vehicle
electric. system/DME control module
present

When I monitor live all 8 cylinders for misfire monitoring while engine running idle I get:
Misfire counter cylinder 7.........10 times (in about 1 minute time)

I have scheduled the spark plugs change in 10 days (not possible before) in another town, do you think there may be something else that I need to consider might need to get fixed?

Thank you all in advance for your great help.

Romandec



I have a Cayenne Turbo 2004. The cel came on.
I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct.
They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


Please use lower case - so much easier to read.

Also, please post codes from Durametric - I have just gone through the same problem on my Turbo and resolved it.
Have them re-check the coil packs and that they are properly connected.
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#7 wvicary

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Posted June 30, 2009 - 05:23 PM

If you have misfires and the MIL light is flashing it is not recommended to drive the vehicle.


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#8 romandec

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Posted July 05, 2009 - 12:10 PM

i just had the spark plugs replaced with porsche ones 99917022190.

when i turned on the engine it appeared worse that with the old plugs and the CEL light came on immediately and solid.

i reset the durametric error codes and ran a new check. Errors on cylinders 3 and 7 no longer appear but now i have a new error on cylinder 8
PO300 (like before)
random/multiple cylinder misfire
detected
present
PO308 (new issue)
cylinder 8 misfire detected
short to ground or positive
present

i remember seeing the mechanic (who was very tired) trying to mount the left side cover on the right side and pushing exactly where cylinder 8 is located. he them realized that it was the wrong cover and used the correct one. i suspect that the original problem was solved by replacing the plugs, and that the mechanic created a new issue. looking at the engine i can see all cables going to coils perfectly perpendicular except for the cable of cylinder 8 that appear bent. could i be right?
i will go back to service and any advice will be highly appreciated.

thanks for your help


I took the car out yesterday for a test drive and used after the Durametric software to see the memorized error codes:

MOTRONIC 7.1

P0300
Random Multiple Cylinder Misfire
Detected
present

P0303
Cylinder 3 Misfire Detected
present

GATEWAY

457 Vehicle electric system control
module (CAN comfort)
no signal/communicaton

Electric system
Current
907 Load management operat. on vehicle
electric. system/DME control module
present

When I monitor live all 8 cylinders for misfire monitoring while engine running idle I get:
Misfire counter cylinder 7.........10 times (in about 1 minute time)

I have scheduled the spark plugs change in 10 days (not possible before) in another town, do you think there may be something else that I need to consider might need to get fixed?

Thank you all in advance for your great help.

Romandec



I have a Cayenne Turbo 2004. The cel came on.
I went to the local Porsche service and they said it had misfires in several cylinders.I checked with Durametric and it was correct.
They replaced ignition coils. (Spark plugs were replaced last year 8000 miles ago). The car still does not run smoothly so I checked today with durametric software myself and verified that only cilinder 7 still has misfires. Someone suggested a compression problem. Please advise. What could it be? Thanks for your help !


Please use lower case - so much easier to read.

Also, please post codes from Durametric - I have just gone through the same problem on my Turbo and resolved it.
Have them re-check the coil packs and that they are properly connected.

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#9 romandec

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Posted July 05, 2009 - 12:15 PM

i just had the spark plugs replaced with porsche ones 99917022190. when i turned on the engine it appeared worse that with the old plugs and the CEL light came on immediately and solid. i reset the durametric error codes and ran a new check. Errors on cylinders 3 and 7 no longer appear but now i have a new error on cylinder 8 PO300 (like before) random/multiple cylinder misfire detected present PO308 (new issue) cylinder 8 misfire detected short to ground or positive present i remember seeing the mechanic (who was very tired) trying to mount the left side cover on the right side and pushing exactly where cylinder 8 is located. he them realized that it was the wrong cover and used the correct one. i suspect that the original problem was solved by replacing the plugs, and that the mechanic created a new issue. looking at the engine i can see all cables going to coils perfectly perpendicular except for the cable of cylinder 8 that appear bent. could i be right? i will go back to service and any advice will be highly appreciated. thanks for your help


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#10 Twincharger

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Posted July 06, 2009 - 03:33 AM

i just had the spark plugs replaced with porsche ones 99917022190.

when i turned on the engine it appeared worse that with the old plugs and the CEL light came on immediately and solid.

i reset the durametric error codes and ran a new check. Errors on cylinders 3 and 7 no longer appear but now i have a new error on cylinder 8
PO300 (like before)
random/multiple cylinder misfire
detected
present
PO308 (new issue)
cylinder 8 misfire detected
short to ground or positive
present

i remember seeing the mechanic (who was very tired) trying to mount the left side cover on the right side and pushing exactly where cylinder 8 is located. he them realized that it was the wrong cover and used the correct one. i suspect that the original problem was solved by replacing the plugs, and that the mechanic created a new issue. looking at the engine i can see all cables going to coils perfectly perpendicular except for the cable of cylinder 8 that appear bent. could i be right?
i will go back to service and any advice will be highly appreciated.

thanks for your help


Check bother the Coil and Injector wiring/plugs for any shorting or lack of insulation.
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#11 romandec

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Posted July 08, 2009 - 07:04 AM

i just had the spark plugs replaced with porsche ones 99917022190.

when i turned on the engine it appeared worse that with the old plugs and the CEL light came on immediately and solid.

i reset the durametric error codes and ran a new check. Errors on cylinders 3 and 7 no longer appear but now i have a new error on cylinder 8
PO300 (like before)
random/multiple cylinder misfire
detected
present
PO308 (new issue)
cylinder 8 misfire detected
short to ground or positive
present

i remember seeing the mechanic (who was very tired) trying to mount the left side cover on the right side and pushing exactly where cylinder 8 is located. he them realized that it was the wrong cover and used the correct one. i suspect that the original problem was solved by replacing the plugs, and that the mechanic created a new issue. looking at the engine i can see all cables going to coils perfectly perpendicular except for the cable of cylinder 8 that appear bent. could i be right?
i will go back to service and any advice will be highly appreciated.

thanks for your help


Check bother the Coil and Injector wiring/plugs for any shorting or lack of insulation.


I went to another mechanic today. Cyl 8 had the injector position moved, the connector of the wire to the coil with the safety lock broken, not plugged in the coil completely and therefore this caused the big irregularity cyl 8 (CEL). Pushed it all the way in, the big irregularity went away and then I ran a Durametric check. Still had misfires on cyl 8. Took out the new spark plug which had the electrodes almost touching each other. Fixed distance, now car runs perfect, no durametric error codes.
Thank you all for the invaluable info and help you provided.
Now the problem is that with vibrations the 2 connectors with broken lock may eventually disconnect from the coils. Can i buy new ones without replacing all wiring?
Thanks again. Cheers.
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