gio_73

CEL came back...

Everytime the light has come on, these have been the conditions:
- Parked for more than 10-12 hours
- Parked in an underground garage
- Once started, accelerator is left untouched. Before it reaches operating idle, the light comes on
- No change in engine sound or movement

The only other thing that stands out is the engine vibration which is present at all times, hot or cold. This can be passed off as normal, but it does vibrate a little more than a friends 996 C2.

I appreciate the continued support.

gio_73

To be more precise, the vibration is at idle only, and is less noticeble with the A/C on, since it idles a little higher.

utkinpol

buy or find somebody with durametric or piwis to read CEL codes.

my most recent CEL was related to me pulling out miltiple brakers and placing them back in wrong spots so O2 sensor heaters had no power. go figure.

gio_73

What are the chances that my lifters may have to be replaced?

Macster

Well, it is not plugs, coils, gas or rodents...

We need to know what the error codes are.

Sincerely,

Macster.

Macster

Pretty slim. There's other things that can cause the symptoms before the lifters come under suspicion. With a PST2 or PIWIS there are tests the tech can command the DME to do that can help id the lifters or the VarioCam system are at fault.

Sincerely,

Macster.

gio_73

The car is going back to the dealership on Monday... I'll keep everyone updated with the results.

gio_73

Update...
Dealership diagnosed further. They concluded that the DME had old software. They upgraded the software and told me the problem was solved. I questioned this, and I knew this could not be the cause, however I gave them the benefit of the doubt. Picked up the car last night, and this morning... CEL. Codes are still random misfires from random cylinders.

The car does run rough. My "slight vibration" at idle from recent posts were just from denial.

Any other ideas/suggestions?

Who else can I bring the car to in the Montreal area?

Thanks for the support!

utkinpol

try to pursue dealer again, if you have warranty make them to replace all coils. coils should be on warranty. spark plugs may be not.
i`ve heard of cases where DME itself may have to be replaced, you want dealer to take care of this.

gio_73

Had another conversation with the dealer today. After expressing my dissatisfaction with the way they are going about this issue, I find out that the DME had registered over-revs... The first time i hear of this.

Although im scheduled to bring the car back next week, i thought i might share this with you guys and maybe you can share your thoughts.

utkinpol, the car does not have warranty, also all the plugs and coils have been changed out. The DME is still a suspect...

Macster

You need to get a full readout of the overrevs and post here for analysis.

There can be mild overrevs which are harmless but there can be the more serious kind.

Depending upon the severity of the overrevs (the rpms at which the overrev events occurred) this can result in valve damage that results in ongoing misfires.

What can happen is the engine overrevs severely enough that piston and valve contact are made. Under some cases this results in almost immediate engine failure.

But in other cases it can result in one or more bent valves. The valves will not straighten out on their own.

Eventually, if the engine is run enough and run at higher rpms, the head will almost certainly break off and the engine is almost certainly ruined when this happens.

In the meantime the DME registers misfires because one or more cylinders are weak, weak from the less than acceptable combustion chamber sealing due to the bent valves.

The valves may burn over time too as the hot combustion gases heat the portion of the valve head up that does not make full contact with its valve seat. It is while the valve is on its seat that alot of the heat is transferred from the valve heat to the valve seat and to the head and eventually to the coolant.

Sincerely,

Macster.

gpjli2

I would want to see a compression/leakdown test and look at the plugs.

s2Rick

gio -73. I'm having random misfires also as stated new coils, new plugs. Local indy ran fuel injector cleaner under 30lbs of pressure and did not fix the problem, thought it may have been ethanol gum-up problems. My car sat for 3 wks then i started having problems.His scanner says code p0300 which is random misfires.Don't know what to do as the dealer is 90 miles away and i really do not want to go.Let me know any new info you may have. Thanks

gio_73

Update:
Through durametric we were able to see that all MAF perameters are where they are supposed to be. The only thing which looked out of the ordinary was the power after the alternator. We found out it was the wiring, so we replaced it. It did not solve the issue, but it does bring the right amount of power to the DME now. Compression/leak down was done as well, and everrthing checks out. Actually the engine has very good compression for a 6 year old engine. The next step was to check for vacuum leaks, and some suction was detected. Long story short, my intake was removed, and we noticed that the whole inatke manifold system was from the 996 model... Now many quesions arise: Could it be it was replaced with a 996 intake? Since its a early 997 (build date 11-04) that it could have left the factory with a 996 manifold? Maybe this is what it causing the rough idle and misfire?

What are your thoguths?

Cheers,
Gio

utkinpol

did you try to take off all coils/plugs from left side and put them on right side - essentially swap coils around and check if misfires will also 'shift' around to the other side?
or do you get misfires on all cylinders?

MAF 'reading' is one thing - but did you try to put in actual new MAF sensor? or at least give old one a good bath with maf cleaner aerosol?