OBD-II Reports

[djgross]

I am researching OBD-II reports: What I would like to know is:

- What information is contained in them?

- Is some of the data permanent or can all of it be erased?

- Would a dealer generally keep a permanent record of each report made so that a history is maintained?

- Does Porsche receive a copy of the reports?

- Is there any information available on how to read a report?

Thanks,

Duane

[Tool Pants]

And why do you want to know this?

[Loren]

As a Contributing Member you can read the TSB 0101 0335 New Format of OBD II Reports (dated 10-05-01) here

[djgross]

Tool Pants

Sorry for the long post, here is why I want to know.

- I have been told that my engine needs to be replaced. The dealer’s diagnosis has progressed from a leaking oil separator, (white smoke from the exhaust) to bad rings to bad rings, bent valves and cylinder wall damage.

- The car has been at the dealer for 11 weeks. From my perspective the information I have been given has changed over that time. I am trying to find out if there is a paper trail that objectively traces the diagnosis and work performed on the car.

- I have owned several vehicles with higher mileage and not encountered these problems. The car has 105K miles; it has never been to the track, DE or other type of event. It has been a daily driver, mostly highway miles. I have followed the recommendations to not exceed 4,000 RPM until the engine reaches operating temperature. All scheduled maintenance has been performed at a dealership. I do not drive the car hard; I have averaged around 30K miles on each set of tires.

- The car was fixed and running well at one point, the dealer wanted one more person to drive it. During this test drive the car started smoking again and had to be towed back to the dealer. This is when the bad rings were diagnosed and I was told that the motor needed to be replaced.

- I asked for a meeting to discuss the issue. It was agreed that a bore scope test would be performed. Here is the diagnosis:

Cylinder:

- 1: Good cylinder

- 2: Large half moon gouges in cylinder, shows signs of small cracks in cylinder

- 3: Good cylinder

- 4: 2 half moons on pistons, cylinder wall is scorched

- 5: Good cylinder

- 6: Small single half moon on piston-slight scoring on cylinder wall

Analysis:

- Rings are worn-but not completely failed.

- Bore scope traced piston to valve contact - causing bent valves to misread fuel/air mixtures - thinks its getting to much air because valves are not seating properly. Cylinder 2 is the worst, followed by 4 and 6 - with cylinder wall damage.

- Cause: Over rev-or close to over rev condition/possible miss-shift

- Ring failure can be gradual/but can also show rapid declination

- Recommendation: replace engine-complete

Compression test:

1: 125

2: 110

3: 150

4: 125

5: 125

6: 150

- It is disturbing to me that with the turn of a key a car can go from running fine to needing to replace the motor. From what I know I should have seen oil burning and been adding oil on a regular basis. I also should have noticed a drop in performance.

- I’m trying to determine if something could have occurred at the dealership that may have taken minor problem to a major problem.

Any insight you may offer would be appreciated.

Thanks,

Duane

[ebaker]

I'd be interested in seeing if there were any over-revs while in the dealer's possession.

[Tool Pants]

Do you have any range 2 over revs? If so how many. If so what are the total operating hours on the engine, and what is the operating hours since the last range 2.

[djgross]

From the OBD report dated 7/16/04:

Boxster (986) DME Vehicle data

Number of ignitions, range 1

636 1909.0h

Number of ignitions, range 2

- -

Operating hours counter

2537.7

Another note:

- The car still has the original clutch

Edited July 22, 2004 by djgross

[Tool Pants]

If you are going 100 mph in 5th gear and shift to 2nd accidently your rpms go way, way up and you can damage the engine. That is range 2. Range 2 is not good but there are cars with range 2 that run fine. I call this rpms driven by the rear wheels. The rev limiter cannot stop this type of over rev to protect the engine.

Now, say you are going 30 mph in 4th gear and you shift to 2nd. The rpms will not be high enough to get you into range 2

Range 1 is when you are under acceleration and hit the rev limiter. The computer cuts fuel to 1/2 of the plugs so the engine cannot rev high enough to damage the engine. I hit the rev limiter almost ever day for 5 years. Range 1 means nothing as the rev limiter protected the engine. In any event, the last ignition in range 1 was 635 engine operating hours ago. So your engine was running for 635 hours since your last range 1. That is a very long time, and I trust it worked just fine.

You have no range 2. If you over reved the car such that it caused engine damage you would have range 2 ignitions. So, did your dealer do something to your car to damage the engine. No. There is no range 2, period. Unless your dealer let your engine run for 635 hours they could not have triggered the last range 1.

The numbers in range 1 and 2 cannot be changed by a dealer.

This is a local guy's 2000 Boxster S. 34,300 in range 1 and 14 in range 2. His car runs fine. Look at the sticker on your door. What year and month was your car made. I do not know if you are the original owner but that car has been driven by "a little old lady." The poof is the range 1 and 2 report plus the fact you have the original clutch on a 100,000 mile sports car.

[djgross]

Tool Pants,

Thanks again for your input.

I guess I’m a “little old lady” because I am the original owner. The car was built-in August or September of ’98. Not sure because the car is at the dealer, but I know it was one just after the summer shutdown.

Any thoughts on how the valves could be bent?

[Tool Pants]

Next question. Is your engine sleeved like they did back then?

If you have not already done so you need to call Porsche in Atlanta. I think the number is 1-800-PORSCHE.

Valves get bent when a piston hits it while the valve is open.

[djgross]

Sorry, my question was not clear enough. I should have asked, with the information presented, how could have the piston impacted the valves?

Do you think with the mileage on the car that the rings should have worn out?

[Tool Pants]

(1) There is no information presented other than a conclusion which is not supported by the fact you have no range 2.

(2) Piston rings are wear items and with 105,000 you would expect them to have wear. As they wear you have some loss of compression - which you do have in some cylinders - but the report says it is due to the bent valves.

Do you know if the engine was sleeved?

[djgross]

Update:

After a phone call and a letter to the Porsche I had a phone conversation with the zone rep on Tuesday. I had sent him a history detailing the diagnosis on the car. We focused on the bore scope test because he said it was probably the next best thing to tearing down the engine; we also discussed the OBD-II report.

His conclusions were:

- The engine needs to be replace

- He stated that there was no evidence of an over rev failure

- His explained the Ignitions Range1 & 2 sections of the OBD-II report as follows

Range 1 – Is a mechanical over rev – i.e. not caused thru the gas pedal or accelerating; example was from downshifting

Range 2 – Is a serious mechanical over rev

The difference being the RPM range

- Other possible causes given:

Lack of oil

Overheating

Foreign object enter the engine

An internal part failure

- The engine failure is not consistent with a sleeve failure

I know that overheating or a lack of oil did not occur.

I am contemplating taking the car to another shop to verify the bore scope test, don’t know if I would be throwing money away. It is disappointing that the motor would go after 105K miles.

I thought you might want to know about the OBD-II over revs.

Duane

[her_986]

Duane –

Sorry to hear about your engine problems... Just a short story about a friends air cooled 911 engine. He also experienced a valves to piston contact due to a cam chain tensionor failure. Can not say if this is a problem in the water cooled engines. He said that the tension on the cam chain was controlled by engine oil pressure, he thinks that a seal let go… Engine rebuilt time.. :( Lets look on the good side. Due the RMS failures, that do not happen, there should be plenty of fresh rebuilt engines around.. Most likely cheaper than rebuilding yours… Or maybe it's time for a little extra go, like a 3.2 none e-gas(if there is such a thing)… Or go for the gold and do a 996 engine.. :D It looks like you enjoy your ride, so why stop now!!!!

Good luck…

[peterjoyce]

What dealership did you use? I hope it was not Rockville.

[djgross]

Tischer, what's yor exierence with Rockville?

Duane