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misfire


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I have a 03 x50 996 turbo it has 2,600 miles and it has a skip when you just give it a litte gas or when you give it some gas and when it starts to go back to a idle you can hear it skip. It also skips on the road at any speed when you give it gas. It will skip about three times and then it will take hold and go up the 6,000 rmp or so an not skip at all until you let off gas and push it back again. I changed the MAF and it did not help at all. Any idea what i could look for? No codes with a OBII scanner. The left side head was replace at dealer when it had 2,450 miles because of a water leak. I bought it after that and did not drive it before buying it as the car was about a thousand miles from me. I would say it has had this problem after the head was replaced but the owner says it did not skip and the dealer also said it was ok when it left. When it was unloaded from trailer it was very hard to start and it truned over much longer than it should have before starting and when it did start it was skipping. I wish i was not so far away from the dealer that did the work as i would bet it has something to do with the work they did. Maybe a cracked coil or damaged plug. It does have CPO warranty but not sure how that would work on another dealers mistake. What are your thoughts?

Thank You

Jack

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May not be the same issue, but I had one of the heads on a 02 TT X50 replaced due to a porous casting. Dealer had a hell of a time trying to figure out what was causing the misfire and it turns out to be cast material debris from the new head limiting the oil flow to the high lift solenois causing the misfire.

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  • Admin
I have a 03 x50 996 turbo it has 2,600 miles and it has a skip when you just give it a litte gas or when you give it some gas and when it starts to go back to a idle you can hear it skip. It also skips on the road at any speed when you give it gas. It will skip about three times and then it will take hold and go up the 6,000 rmp or so an not skip at all until you let off gas and push it back again. I changed the MAF and it did not help at all. Any idea what i could look for? No codes with a OBII scanner. The left side head was replace at dealer when it had 2,450 miles because of a water leak. I bought it after that and did not drive it before buying it as the car was about a thousand miles from me. I would say it has had this problem after the head was replaced but the owner says it did not skip and the dealer also said it was ok when it left. When it was unloaded from trailer it was very hard to start and it truned over much longer than it should have before starting and when it did start it was skipping. I wish i was not so far away from the dealer that did the work as i would bet it has something to do with the work they did. Maybe a cracked coil or damaged plug. It does have CPO warranty but not sure how that would work on another dealers mistake. What are your thoughts?

Thank You

Jack

Have them check the VarioCam Plus hydralic valve bracket too.

http://www.renntech.org/forums/index.php?s...st&p=126057

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  • 2 weeks later...
I agree with RFM - much easier and faster to remove the bumper and intercoolers. See the spark plug change DIY in the 996TT Maintenance DIY section.

OK i ordered 6 new updated 997 coil packs and installed 6 new Bosh plugs and i still have the skip. I also checked the compression on all cylinders wheile i had plugs out and they were good. The dealer thinks maybe the last dealer that installed the new cylinder head on the left side did not get the engine back in time something about the gear has to be turned all the way to the left and they seem to think the miss is from the cams not being in time on each side. They want me to bring it back down there and they are going to hook it up to machine and see of they can check the timing on each side. Anyone heard of this?

Edited by whiteturbo
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Greetings Whiteturbo:

What they are talking about is the variocam actuator. This actuator is located in the intake camshafts of the engine. It forms part of the intake camshaft sprockets. In other words, both intake camshaft sprockets have integrated the variocam actuators. When disassembling and/or assembling the engine, the mechanic needs to set the camshafts to the original timing position with the engine in top dead center(TDC) using the special Porsche tools(these tools simply maintain the camshafts fixed in there proper position while pistons 1 and 4 are in TDC). Once this is achieved, using another Porsche special tool, the sprocket needs to be rotated counter-clockwise(stated as many as moving it to the left) to properly undo the main camshaft sprocket bolt. If this is not done, the camshaft when tightened will not be in its correct timing position even though the camshafts were fixed with the Porsche tools in there original timing locations. A good way to test if the variocam activate is working properly is to simply activate the system using a durametric system or with the engine in idle, simply applying 12Volts to the variocam solenoid of the bank that is suspected to have the problem. If the system is operating correctly, there should be a noticeable change in engine sound and operation when the variocam solenoid is activated. You can read the thread I started "Porsche code P-1325". There are some pictures that will illustrate what I am talking about. To be honest, I would not expect a mistake of this type in a Porsche certified shop since the service manual is very specific about this topic.

Best regards, Andres

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With regards to the porus head,

After the install, it would misfire and throw some codes (don't know if they are the standard OBDII codes that was thrown) on the test drive. Your description of your issues and their description are pretty similar.

1st step the dealer tried was to sell me new set of plugs + discounted labor saying it was cost effective maintainence. After asking about the condition of the old plugs and wondering why they didn't recommend the change with the engine out, they finally said they have some misfire issues after the test drive. Well they replaced the plugs with "test plugs" as the 1st step in figuring out the problem and it still misfired.

2nd step was to replace three cracked coil packs...still misfired

3rd step...put the engine on the machine to check timing, variocam, etc. Everthing checked out great but still misfired

4th step...have a few different techs and supervisors check to make sure the engine was assembled correctly...looked good to them all but still misfired (don't know if this was done with the engine in or out).

5th step...place SOS call(s) to Porsche techs in germany over the next few days

6th step...tear down the engine again only to find the casting debris in head...problemed solved. Kind of makes you wonder if there was anything else in the head that is now elsewhere in the engine. After the last oil change, I did see a few metal flakes in the oil filter about 0.5 to 1 mm in diameter (6 to 8 pieces in the bottom 1/2 of the filter)...

In any case, it seems like the timing check is a viable next step for the dealer and they should have factory resources to help fix the issue if they get stuck. The casting residue, imho, is a Porsche quality issue so it may have effected more then one replacment head and the factory should be aware of the potential issue. I've always wanted to know if Germany asked them to open up the engine again to look for other general problems or for a specific known problem.

In any case, took them about a 1.5 weeks to figure it out. I think the dealer and the factory did a good job at the end. I always asked "what if you can't find the problem?" and they insisted on "we never had a car that we couldn't fix" so I hope they get to the bottom of your misfire soon.

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With regards to the porus head,

After the install, it would misfire and throw some codes (don't know if they are the standard OBDII codes that was thrown) on the test drive. Your description of your issues and their description are pretty similar.

1st step the dealer tried was to sell me new set of plugs + discounted labor saying it was cost effective maintainence. After asking about the condition of the old plugs and wondering why they didn't recommend the change with the engine out, they finally said they have some misfire issues after the test drive. Well they replaced the plugs with "test plugs" as the 1st step in figuring out the problem and it still misfired.

2nd step was to replace three cracked coil packs...still misfired

3rd step...put the engine on the machine to check timing, variocam, etc. Everthing checked out great but still misfired

4th step...have a few different techs and supervisors check to make sure the engine was assembled correctly...looked good to them all but still misfired (don't know if this was done with the engine in or out).

5th step...place SOS call(s) to Porsche techs in germany over the next few days

6th step...tear down the engine again only to find the casting debris in head...problemed solved. Kind of makes you wonder if there was anything else in the head that is now elsewhere in the engine. After the last oil change, I did see a few metal flakes in the oil filter about 0.5 to 1 mm in diameter (6 to 8 pieces in the bottom 1/2 of the filter)...

In any case, it seems like the timing check is a viable next step for the dealer and they should have factory resources to help fix the issue if they get stuck. The casting residue, imho, is a Porsche quality issue so it may have effected more then one replacment head and the factory should be aware of the potential issue. I've always wanted to know if Germany asked them to open up the engine again to look for other general problems or for a specific known problem.

In any case, took them about a 1.5 weeks to figure it out. I think the dealer and the factory did a good job at the end. I always asked "what if you can't find the problem?" and they insisted on "we never had a car that we couldn't fix" so I hope they get to the bottom of your misfire soon.

I am going to print these out and take them to my dealer. Mine does not have any codes and they say it does not misfire. IN ANY CASE IT SKIPS they can call it whatever they want. I did not own it before the head was replaced but i am sure that is when the skip started. I just have to get Porsche to pay for the repair as it is under CPO until MARCH 1/09. I have the power sterring whine also and they don't want to pay for that either. I have read online that some get the CPO to repair the power sterring and some do not. What dealer did the work on yours? Boardwalk in Plano TX did the work on mine. I would take it back to them but they are 1,000 miles from me. I called them about it and they said it did not skip when they finished it. I also stated before the tech. at my dealer drove it and then had the shop manager ride with him and both said it did not skip. I took him a ride and he agreed it is skipping and sid they would start with plugs so i replaced them and all 6 updated coils. It skipped from the day i unloaded it off trailer. At this point i am sick of it. I still have my 01 non X50 and it has been a perfect car never missed one time in the 4 years i have owned it. I tried to send you a message CCC and it said i could not send one for some reason anyway i want to thank everyone that has helped me with thisn issue. please keep me posted any other info and i will post if i get it repaired.

Thanks Again

Jack

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With regards to the porus head,

After the install, it would misfire and throw some codes (don't know if they are the standard OBDII codes that was thrown) on the test drive. Your description of your issues and their description are pretty similar.

1st step the dealer tried was to sell me new set of plugs + discounted labor saying it was cost effective maintainence. After asking about the condition of the old plugs and wondering why they didn't recommend the change with the engine out, they finally said they have some misfire issues after the test drive. Well they replaced the plugs with "test plugs" as the 1st step in figuring out the problem and it still misfired.

2nd step was to replace three cracked coil packs...still misfired

3rd step...put the engine on the machine to check timing, variocam, etc. Everthing checked out great but still misfired

4th step...have a few different techs and supervisors check to make sure the engine was assembled correctly...looked good to them all but still misfired (don't know if this was done with the engine in or out).

5th step...place SOS call(s) to Porsche techs in germany over the next few days

6th step...tear down the engine again only to find the casting debris in head...problemed solved. Kind of makes you wonder if there was anything else in the head that is now elsewhere in the engine. After the last oil change, I did see a few metal flakes in the oil filter about 0.5 to 1 mm in diameter (6 to 8 pieces in the bottom 1/2 of the filter)...

In any case, it seems like the timing check is a viable next step for the dealer and they should have factory resources to help fix the issue if they get stuck. The casting residue, imho, is a Porsche quality issue so it may have effected more then one replacment head and the factory should be aware of the potential issue. I've always wanted to know if Germany asked them to open up the engine again to look for other general problems or for a specific known problem.

In any case, took them about a 1.5 weeks to figure it out. I think the dealer and the factory did a good job at the end. I always asked "what if you can't find the problem?" and they insisted on "we never had a car that we couldn't fix" so I hope they get to the bottom of your misfire soon.

Did dealer have to remove the head on your car again to fix it. Mine is at dealer and they said they called Porsche and Porsche told me to drive it that with the age on my car and low miles clound be trash in fuel system or something. I am not getting anywhere with getting my problem fixed

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So is the dealer claiming you you have to drive and live with it or drive and the problem will go away? Also, whats the "or something"... if its the fuel filter, can they measure the pressure upline or just change it out? Do they think the current fuel is contaminated so can they drain the tank and fill up with some good gas? Can you drive through a few tanks and if it doesn't go away, take it back before the end of the week before the CPO expires.

I never saw the head or them doing the work, I was under the impression that the engine was dropped out. With the servo on top, my guess is that they may have been able to clear the clog from the top so don't know if the head had to come out again. The part list doesn't show two head gaskets. Someone else on the forum may be better experienced to answer that one.

Hopefully then can rule out the fuel and focus on the "something"

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  • 3 weeks later...
So is the dealer claiming you you have to drive and live with it or drive and the problem will go away? Also, whats the "or something"... if its the fuel filter, can they measure the pressure upline or just change it out? Do they think the current fuel is contaminated so can they drain the tank and fill up with some good gas? Can you drive through a few tanks and if it doesn't go away, take it back before the end of the week before the CPO expires.

I never saw the head or them doing the work, I was under the impression that the engine was dropped out. With the servo on top, my guess is that they may have been able to clear the clog from the top so don't know if the head had to come out again. The part list doesn't show two head gaskets. Someone else on the forum may be better experienced to answer that one.

Hopefully then can rule out the fuel and focus on the "something"

Picked up car at dealer after 3 weeks and they replaced number 4 injector and said it was fixed. I started out of parking lot and it was still missing drove back to dealer and left it. Don't know what to do next they have about 25 hours in it now and have not fixed it. thank God CPO is paying. I still think it has something to do witth the head that was replaced and gave them all my emails but thye are not sure what to do to fix it. At this point i am sick of this car !!!!!!!!!!!

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Most of us buy our cars and really enjoy driving them with minimal problems....but every once in a while a story like this pops up and you really feel sorry for the fellow who seems to have everything go wrong and no one can seem to come up with a solution. The solution is a new engine, but they'll balk at that one....but c'mon, after a number of weeks or over a month and the problem still persists? It's really too bad you've bought a nice car and have had nothing but trouble....

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Most of us buy our cars and really enjoy driving them with minimal problems....but every once in a while a story like this pops up and you really feel sorry for the fellow who seems to have everything go wrong and no one can seem to come up with a solution. The solution is a new engine, but they'll balk at that one....but c'mon, after a number of weeks or over a month and the problem still persists? It's really too bad you've bought a nice car and have had nothing but trouble....

Strange thing the dealer that did the head in Texas said it was not skipping and also the dealer here. The last owner also said it was not. I can't believe that there are so many people out there that can't tell when a car is skipping. It is worse now that it was. I do still have the 01 that i can drive so it is not as bad as it could be. Dealer admits it skips now but can't fix it.

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My sincere condolences for what must be an exasperating and ongoing problem for you. With all the time and fiddeling around they've done all to no avail, it really sounds like they need to tear into that engine....did you say that the warranty was only good till 1/09?

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My sincere condolences for what must be an exasperating and ongoing problem for you. With all the time and fiddeling around they've done all to no avail, it really sounds like they need to tear into that engine....did you say that the warranty was only good till 1/09?

Warranty went out 3/01/09 but was in shop before that date and is still there. I talked to them a few days ago and they said they are going to get the distrect rep to come from Porsche to look at it. Porsche says drive it because it shows nom codes. Why would i want to drive anything skipping much less a Porsche?

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  • 4 weeks later...

Update i picked up my car today a little shy of the dealer keeping it for 9 weeks. They started replacing all the injectors and found the injector port on number 4 cylinder had not been drilled all the way out from the factory.It looked like it was about 1/4 open. they opned up the port and replace all injectors and it runs very well now. Thanks for all the help. I would say i have the one in a million cars made with a problem like this Man do I have luck or what?

Thanks

Jack

Edited by whiteturbo
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Update i picked up my car today a little shy of the dealer keeping it for 9 weeks. They started replacing all the injectors and found the injector port on number 4 cylinder had not been drilled all the way out from the factory.It looked like it was about 1/4 open. they opned up the prot and replace all injectors and it runs very well now. Thanks for all the help. I would say i have the one in a million cars made with a problem like this Man do I have luck or what?

Thanks

Jack

Was this injector on the same head that was replaced?

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Update i picked up my car today a little shy of the dealer keeping it for 9 weeks. They started replacing all the injectors and found the injector port on number 4 cylinder had not been drilled all the way out from the factory.It looked like it was about 1/4 open. they opned up the prot and replace all injectors and it runs very well now. Thanks for all the help. I would say i have the one in a million cars made with a problem like this Man do I have luck or what?

Thanks

Jack

Was this injector on the same head that was replaced?

No driver side head was replaced and number 4 is on the passangers side.

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These are the horror stories that make you thankful you got one that only has a problem passing a gas station....Glad you're back on the road. I guess your CPO had a real workout. Turns out to be a quality control problem with a part.....That will be one for the Porsche unusual file.

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