dstrimbu

Soooo, I'm frustrated.

I've read several threads here (Dario's most recently) regarding a potential fuel system issue with the 997. I will be scheduling shop time later today (and unfortunately, due to work / travel / July 4th, the P-car will be sleeping for a week or so... ).

The C4S turned 2,500 miles yesterday. It's been running like a dream - smooth, powerful, absolutely no issues. I knew that the clock was ticking, though... good things can't go on forever.

Friday night, I stopped at a buddy's to show him the car. I distinctly remember his comment when I opened the engine bay with the motor running - he remarked as to how smooth the engine was at idle. I was amazed, too - not because I didn't know it was smooth, but watching the damned thing run really brought the point home.

Saturday, I ran a few errands. Sunny to partly cloudy - daytime low 60, high around 80, high humidity but not opressive. Again, the car ran like a dream.

Sunday, we had a party for the family. I spent about two hours giving rides to my nieces and my son's friends. My sister drove the car (wow, she fell in love - and she did a great job handling it - her time in the VW bug must have prepped her to be a 911 driver... ) - and so did my brother-in-law. Again, they were most respectful and the car ran perfectly. Weather was the same, except for spotty rain during the afternoon.

I had one more ride to give, and I was down to approx 3 gallons of petrol, so I pulled into the BP and topped 'er off with 14.5 gallons of Ultimate (93 oct). I need to make this point - I buy almost all of my gas at this station, and I 've never had an issue (except for the price... <g>). I live 0.7 miles from the station, BTW.

Ran back home, picked up the last thrill-seeker. We spent 15 minutes cruising about 10 miles, and I pulled back into the garage. I figured that I'd wash it up in the pm after everyone left. This was around 5pm.

At 7pm, I set out my buckets, hose, microfibers et al, and jumped into the car to pull it outside (cloudy and cool, at this point). I turned the key, and <crank> - no start. That's never happened before.

Ok, let's try again - turn the key, and <vroom> - she fires right up. However, the idle did not stabilize - in fact, it was as lumpy as my old LT-1 Corvette. Tapping the throttle smoothed the engine dramatically, but upon return to idle, the lumpiness came back immediately. The car was not shuddering, per se - but it sounded ratty and was clearly unhappy (if an engine can be unhappy - maybe I'm projecting, eh?) I backed out of the garage, stopped the motor and washed the car.

At 8:30pm, I started the engine (I figured - one shot around the block wouldn't hurt) - and immediately, I get a check engine light and the message "Check Engine - Visit Workshop) in the speedo display area. Rough idle still present, off idle seemed OK. Needless to say, I pulled the car back into the garage and shut it down...

Soooooooo, questions:

1.) I know that Dario, MDOnline and others have reported rough running at various RPM ranges, but has anyone ever thrown a Check Engine due to this?

2.) Am I correct in _postulating_ that this is a fuel issue? Either that, or - the timing is just too perfect...

3.) Is it safe to drive the car to the shop (assuming that it continues to run smoothly off-idle)?

Sorry for the long post, but I needed to think thru it myself to be able to replay the scenario for my mechanic... any comments or suggestions are appreciated.

-don

Queram

I also have a 2006 C4S and here is what I recently experienced. I dropped the car today and will have it tomorrow hopefully PIWIS will provide answers.

I filled her up 10 days ago when the range was 30 km, so I got almost a full tank. I left the car in the garage to drive it next morning for the 599 GTB introduction. I started my car and drive off. Everything was fine for the first 5 km. I was at a red light and the car started to shake really bad and idled funny. Sort of like someone was pushing the car from the side. The light went green and everything went back to normal and at the next light it did the same thing again. This time I had the yellow flashing check engine light and visit workshop warning. This repeated 4 red lights and I stopped and called Porsche emergency. I was really pissed cause it was a one time event and the track was 80 km autobahn trip away. The tech I talked to said it was probably bad gas and told me to put gas (I had full tank at the moment) I decided to take the risk and go to the track. I averaged 230km/h on the autobah and she consumed 2/5 of the tank. I filled her up and she has been fine since then.

Tomorrow when I get the car back hopefully I will have a solid answer to tell you if it was only gas(which I think it was). We probably have the same problem. Shakey idle and engine at stop, everything is fine once moving.

I drove the car 400 kilometers after this happened partially trusting the fact that I was advised from Porsche to do so.

I hope these help I will update this thread tomorrow.

1999Porsche911

It seems like you want to take real good care of your new car, so I suggest 2 things.

1. Get an OBD scan tool so you know what is going on with your car,

and

2. Never,willingly, run your gas tank down low as you encourage moisture and sediment to enter the fuel system.

gpjli2

This may be superstitious, but I never have had a problem w Shell 93. The one instance of surging I experienced was following use of Amoco Ultimate. I would stick w one brand of gas unless you have a problem, then experiment. Also verify a tight fit of the gas cap after filling up. Good luck.

dstrimbu

That's really funny, gpjli2 - there's a Mobil station across the street from the BP, and I almost turned in there... but I made a last minute decision to stick with what works... wonder if it would have been different if I'd filled up at Mobil.

Yeah, I do the "Drehen bis click" thing <g> when I put the cap on - then give it couple extra clicks. It seems to be tight, I've never smelled gas at any time from the car...

Thanks for the reply,

-don

dstrimbu

Thanks Queram - glad that you made it to the Ferrari event; sorry that you had to deal with this problem...

Let me know what you discover. I will do the same, although I likely will not get the car into the workshop until 05 July.

-don

dstrimbu

Understood, '99 911, I generally fill the 997 when it reaches 1/2 tank; car has been full 75% of the time since I purchased it in February.

What scan tool do you recommend? Peake? I have a Peake for the BMW, but it' pre-OBD, so it certainly won't work for the 997.

Thanks for the reply,

-don

Stephenkng

1999Porsche911, can not agree more on your comment. NEVER run your tunk to almost empty before re-filled. When there is a little below half tunk, you should re-filled it. I have read a lot of post here for the similiar issue, they all wait till it empty before re-filling.

1999Porsche911

There are numerous Scan Tools out there that will do the job for you rangin from about $100 - $400. The one I have is a commercial one that is not offered anymore. Do a search and you'll get a wide variaty of info. Make sure to get one that will record specific sensor readings.

The autoenginuity tool is reportedly a good choice.

http://www.autoenginuity.com/

500

Thank goodness during the 8:30 start you finally got a check engine light, as without it things could have been very difficult to properly diagnose. I was always told the OBD2 was very sensitive and just the slightest misfire would trip a check engine light, as you have seen first hand, the first two times brought no light. I sure she'll be as good as new very soon :-)

mdonline

Dstrimbu,

No my car never showed the "check engine" light. As you said, it was clearly very UNHAPPY. Felt like someone is choking the life out of it, gagging like it was not getting enough air. I brought it to the dealer and they ran diagnostics on it, but found nothing.

It is a good thing (well..not good) that the engine light came on. That means that the computer will register something. It will be interesting to see the computer will say when they hook your car up. Please let us know.

1999Porsche911

One of the big advantages of a scan tool is not that it shows you what the code is, but that you are able to see, in realtime, what the sensors are doing. Everyone should know what each sensor's normal reading is, under various conditions. This will allows you to notice any changes in the engine if you do have a problem, whether you get a CEL or not. What is normal for one engine may not be for another.

dstrimbu

Hey all:

I called Napleton Porsche yesterday afternoon. I have an appointment for the 7th of July (what, a holiday weekend with no 997?!!). That's the best I could do with my travel schedule...

Also, they are recommending flatbedding the car down to the dealership; I will call Porsche to confirm this action. As Queram reported earlier, Porsche told him to drive his car - so it may be that the dealer is just being supercautious.

I will keep all of you up to date. Damn, the sun is out today, too... ... but I'm sure it's temporary. We've had torrential rains for the last few days.

(I can't believe how much this car affects me... I don't think that I've ever gotten this upset when my kids are sick... )

-don

Queram

Ok here it is what PIWIS came up with : NOTHING

When I told the service department that I saw the yellow flashing check engine light and visit workshop warning, they told me that flashing check engine light error code is stored temporarily and it is cleared from the memory if you shut the car down and when you start the next time if everything is ok than that error code is gone. The car is healthy with no diagnostic problems and it drives and feels well as well.

I believe that it was the gas, I most certainly can say that this car is very picky on gas and you can almost feel it immediately if it liked the gas or not.

BTW we have 95 and 98 and 100 octane pump gas here (the octane reading is alittle different than USA) and I always used 98 and 100 octane on my M3 and other family cars. Porsches (all model range) have idle problem with anything but 95 so right now we are recommended to use only 95.

Dstrimbu let us know off the outcome when you get the chance. I am positive that your car is alright as we have pretty much the same symptomps. Good luck!!

dstrimbu

Thank you, Queram, for the feedback. It is late evening Tuesday here in the US, and I have to travel for work tomorrow and Thursday - so I will not be able to try the car again until Friday afternoon. I promise to keep you updated.

Yes, our octane rating is ((R + M) / 2 )) or [ (Research Octane + Motor Octane) / 2 ] - not sure how octane is rated in Turkey, but ours is an average of two standards. Here in the Central US, we can get 93 - but nothing like what is available in your homeland...

I'm glad that your problem was transient; I can only hope that mine is the same!

Cheers,

-don