riley6

Loren,

Any advice?

Steve

Wow. I have this exact CEL problem/codes. The CEL usually flashes for a few seconds around 3000 rpm (steady throttle) then stops. I tried to find the source some months ago; no one fully figured it out. I had an 02 sensor replaced (ahead of catalytic), but the CEL soon returned. I then decided to ignore it since it runs fine. Bill, has the CEL come back since the flywheel replacement? Is there a way to fix the problem without replacing the flywheel? Any help is greatly appreciated.

Steve

I have a 2002 911 Turbo that I acquired 60 days ago and on Monday the check engine light came on. The car passed smog when purchased and now has 50k miles. I was near a Dealer and they read the code but since it was closing time they did not really go over the print out they gave me. The Service person at the Dealer noticed that the inside of the exhaust tips were white, both of them, indicating lean combustion.

I have a 13 page listing and there are 5 Faults. However, these Faults occurred at Operating Hour 1450 and the car is now at Hour 1650 (given in the POSIP (?) section of the listing).

The Faults are: P0300 Misfire detection [P0306 cylinder 6; P0304 cylinder 4; P0305 cylinder 5] and P0040 Oxygen sensors in front of cat. conv. switched.

So are these are old Faults which happened 200 hours ago (~6,000 miles ago) and are no longer a problem?

The first four Faults listed above give the "last state:" Operating Hours as 0.1 larger than in the "1st state".

The Fault P0040 has the same 1st state Operating Hour of 1450 but only blanks for the last state entries. Is this still a problem?

The output reads:

P0040 Oxygen sensors in front of cat.

conv. switched

intermittent

not present

Lamp off

1st state: last state:

Signal implausible Signal implausible

Frequency: 1

Clear Counter 10

Fault time: 0 s

Check Engine on: Driving Cycle 001

Check Engine off: Driving Cycle 003

Lambda value is 0.01 and 0.00 for bank 1 and 2.

ECTS: 83 in 1st state

Operat. hours counter: 1455.0

OBD II code P0040

Under the Freeze Frame information: O2 sensing is control active, both banks.

Load: 9.4 %

ECTS: 82 deg C

Oxygen sensing: 22.6 %

O2 sensing adaption: -1.6 % (negative % ok ?)

O2 sensing, bank 2: -20.4 %

O2 sen. adap., bank2 -3.2 %

RPM: 3080

Speed: 75 km/h

Fault entered by: On-board diagnosis

My wild guess is that if it is running lean then there could be a problem with the fuel supply: fuel pump, fuel filter and/or ?

Should that have thrown a Fault?

From the renntech Forum there was: motor cuts out after gas fill-up: there was a check valve on the vapor recovery line that was getting stuck open because a carbon canister on the fuel recovery system started to disintegrate (the carbon particles sat in the seats of the check valve and would not let it seat (close) properly) - reasonably easy fix.

Currently, my choices are:

1) take it back to the Dealer and let them try at it,

2) take it to an independent shop which does have cheaper labor rates and a history of racing Porsches in the 1990's, or

3) start replacing things at home.

UPDATE (May 14): I did Option 2, took it to an independent shop.

The spring connecting the dual-mass flywheel is allowing too much flex. This affects the timing and the confused computer sets the timing to zero (and this leads to a misfire?). Will post again after flywheel is replaced.

UPDATE (May 23): Replacing the Dual-Mass flywheel cured the problem. Check Engine light only came on when driving as the spring in the flywheel only affected the timing when under the load of moving on the road. Installed a single mass flywheel and had to also replace the O2 sensor before the cat on the right side in order to get the computer to reset for the light weight flywheel.

The exhaust tips are no longer the white color, they are now black and so it may have been running lean due to the timing confusion.

(The engine operating hours are at 1450 and we do not know why the POSIP (Porsche Side Impact Protection) has 200 more operating hours.)

Check the 996 DIY area - 996 TT is pretty much the same. As a matter of fact the pics in that DIY are from a 996 TT.

Thanks. I will give it a try next time. I didn't see a brake bleeding procedure though?

I'm looking for a procedure with pics on how to change brake pads and bleed brakes; I'm tired of paying grease monkeys for everything :P I don't know where to find it. Thanks.

I'm confused....a reputable shop as you call it and they don't have a Porsche scan tool. There is no substitute. Until we get the actual codes we would just be guessing.

Yes they are well known in Delaware and race too. But I think they deal with mostly older Porsches which is maybe why they didn't have the tool before. The owner even confessed that he doesn't like the new ones as much. I'll let you know when I get the diagnosis.

..he's everywhere....here, Pelican, SixSpeed, RennTech, Rennlist, 911Turbo....virtually everywhere.

Actually I have set my browser to bring up certain sites...and contrary to popular belief, I just focus mostly on 996 and especially 996TT. I learn a lot from everyone and when I can I help out. BTW, what is Pelican? Also on flat-6, rennteam and turboflatsix.

Back to the topic Wross :P The car is in the shop but the tool is reading no code, so they ordered a Porsche reader. The car drives fine according to me and them, despite the CEL blinking for 5-10 seconds and stopping, while driving. Any clue what code would not be read by a generic reader?

WROSS is like the CIA....he's everywhere....here, Pelican, SixSpeed, RennTech, Rennlist, 911Turbo....virtually everywhere.

LOL...I need to join some of these other boards too.

blinking cel is NOT good...you should not drive it....did they inspect the coil packs when they changed the plugs?

Could it possibly be something serious? :( It runs hard and smooth; maybe bucks/sensitive throttle alittle in 2nd gear at low rpm.

blinking cel is NOT good...you should not drive it....did they inspect the coil packs when they changed the plugs?

I'm not sure if they did, but taking it back in the morning! They are supposed to be a reputable porsche mechanic in this area.

So do you split time between here and 6speed?

Is there any operation that correlates to 3000 rpm? I spoke to soon the light back on :angry: , but it seemed to come on/blink at a sustained 3K rpm.

The baby is ok :D , she just needed new sparkplugs. Looks like there weren't changed at 30K miles.

I'm taking it to a local reputable shop tomorrow to get a complete diagnosis, then I will go from there depending on what the problem is.

Do you think I'll be ok driving the car 2 hours with the light on (still running without problem)? The dealer wants me to bring it back to him and if I take it local he is not willing to pay the consumer labor rate, as he can fix it in-house (so he says).

Thanks guys; I will do that.

So I shouldn't even bother using the goods I bought from AutoZone (Techron and MAF cleaner)?

P0300 Misfire Detection (Sum Total)

P0304 Misfiring, Cylinder 4

P0305 Misfiring, Cylinder 5

P0306 Misfiring, Cylinder 6

Did you get a CEL?

If not these corrected themselves.

If you did get a CEL then the most obvious causes are spark plug coils or spark plugs.

Since it is only on one side it could be the camshaft control for that bank.

Yes I got the CEL. It temporarily cleared this morning but returned, although the driving characteristics didn't change. Camshaft control? I don't like the sound of that :o

If you didn't see my first post, I just bought this car from an out of state dealer, so he owes me to get the light cleared. But I don't want to go back if I don't have to, maybe I can have it done locally. Do you think cleaning the MAF or adding some Techron fuel cleaner could solve it?

Thought I'd start a new topic. My 996TT showed a P0300 code - 304,305, 306 at AutoZone today. BUT it runs fine, maybe alittle turbo spool up lag at slow speed (2nd gear) but this may be the car's nature (just bought it). Any ideas?

I went to AutoZone to get the code. It is registering a P0300 - 304, 305, 306. Plugs I'm told? I'm also going to clean my MAF today or tomorrow. How much would/should plugs be? I want to have it done local and have the out-of-state dealer pay for it.

welcome to renntech :renntech:

we're the same over here....get a durametric, get the codes, then post the codes and we can help.

small world i see :P

Hello all. I just purchased a 2002 silver Turbo 6speed :jump: . This is my 2nd 911T (3rd Porsche). I look forward to spending alota time here ;) .

Now I do have a slight problem I need some advice on. The check engine light came on soon after I drove off. I test drove it a couple weeks before; and it drove fine (no light), did not hesitate or idle erratic. I went back and they got a misfire code (not sure which one), so they said drive it home and if the light reappeared to come back. On the way home, it lit up a few times but went away; then about an hour in to the drive it came on permanently. It still ran/runs good with the light, I can't detect a problem. The dealer said it is likely a plug or wire and to try fuel system cleaner in it to see if it clears. If not, they will take it back and address it. Any info would be appreciated :) .