RMS failure, 10 days out of warranty

[coleta]

JFP,

This is true. But it seems the value that is read while the car is running is a value that the DME calculated during cranking. So if the relationship of the cams to crank changed while the car was running and the car has not been turned off and re-cranked the deviation value will not change. The car would have to be re-started so that during cranking the DME can recheck this calculation and then display the new value while running.

I know many cars that work like this, but I don't know if this is the case with Porsche.

If you or anybody else has actually seen the deviation values change while the car is running, then this will prove that Porsche's system is different than most out there.

[JFP in PA]

JFP,

This is true. But it seems the value that is read while the car is running is a value that the DME calculated during cranking. So if the relationship of the cams to crank changed while the car was running and the car has not been turned off and re-cranked the deviation value will not change. The car would have to be re-started so that during cranking the DME can recheck this calculation and then display the new value while running.

I know many cars that work like this, but I don't know if this is the case with Porsche.

If you or anybody else has actually seen the deviation values change while the car is running, then this will prove that Porsche's system is different than most out there.

I have, and they do change with the engine running, that is how you test the VarioCam, you get values at idle and at higher RPM's. For example, on a 3.4 VarioCam, you set the Durametric for “actual values” and then select the cam position function, and you will see the values change starting at about 1,500 RPM and moving up to higher values up to around 5,000 RPM.

There have been threads, with data, on this site and others on this exact topic……………

Here ya go: Live cam deviation values thread on Rennlist and a more detailed one: Cam deviation values thread on RennTech

Edited January 25, 2011 by JFP in PA

[coleta]

Thanks JFP. Great links. snorth54 post seems to support my above claim that deviation never changes because it's a value that is only calculated during cranking, because it's a reflection of base mechanical timing.

He recorded:

The camshaft position 1 deviation is always 1.28 regardless of RPM

The camshaft position 2 deviation is always -0-09 regardless of RPM

Actual angle is totally different and does change dynamically because it displays, not the mechanical base timing, but the actual movement of the variocam mechanism.

He notes:

At 3522 RPM the Spec angle for inlet camshaft bank 1 is -40 and the Spec angle for camshaft bank 2 is -40

At 3522 RPM the Actual angle for inlet camshaft bank 1 is -39.65 and the Spec angle for camshaft bank 2 is -40.12

The deviation and actual values should mean the same thing regardless of whether it's variocam or variocam plus. The only differece would be in the actual values themselves, @25 max for the former and @ 40 for the latter.

Based on your experience, does this make sense (as this is all theoretical)?

Thanks again

[JFP in PA]

Thanks JFP. Great links. snorth54 post seems to support my above claim that deviation never changes because it's a value that is only calculated during cranking, because it's a reflection of base mechanical timing.

He recorded:

The camshaft position 1 deviation is always 1.28 regardless of RPM

The camshaft position 2 deviation is always -0-09 regardless of RPM

Actual angle is totally different and does change dynamically because it displays, not the mechanical base timing, but the actual movement of the variocam mechanism.

He notes:

At 3522 RPM the Spec angle for inlet camshaft bank 1 is -40 and the Spec angle for camshaft bank 2 is -40

At 3522 RPM the Actual angle for inlet camshaft bank 1 is -39.65 and the Spec angle for camshaft bank 2 is -40.12

The deviation and actual values should mean the same thing regardless of whether it's variocam or variocam plus. The only differece would be in the actual values themselves, @25 max for the former and @ 40 for the latter.

Based on your experience, does this make sense (as this is all theoretical)?

Thanks again

Theoretically, CPS deviation value should be zero at an idle, unfortunately in the real world, it never is due to tolerances or wear on the components, and you always end up with a slight odd value. The big issue with checking the IMS condition using cam deviation values is that, at idle speed, the deviation value remains steady, and is not moving around (usually back and forth), indicating that the cams are moving back and forth, which can only mean bad news at the IMS. So the DME is seeing the deviation change in real time, not just during cranking. When you do see the deviation values moving back and forth at an idle, you will typically also see the actual values jumping around as well at just about any RPM, and this is particularly disconcerting when the engine transitions from increasing to decreasing RPM.

On an engine in good condition and with a solid IMS, you will still see the slightly off zero CPS deviation values at an idle, but they will not change and will indicate a fairly constant value. When the VarioCam (or VarioCam +) kicks in at elevated RPM's, the deviation values should also remain fairly steady as the actual values change, but the actual values should also remain relatively steady at a given RPM as well. The differences between the indicated deviation values and the actual values are usually fairly close, but not always exactly the same.

Edited January 26, 2011 by JFP in PA

[coleta]

Great info. Thanks again JFP.

[harperb]

In January of 2010, I had the engine in my 05 997 S replaced for free by Porsche with a new engine due to severe scoring on the #6 cylinder wall (Thank You Porsche!), and am wondering if the new engine that was replaced should have any of these RMS/IMS failures?

I know it's a defect inherent in the 997.1 engine design (and 996 as well), but am hoping this defect has been worked around or resolved effectively with the new replacement engine.

Edited January 27, 2011 by harperb

[JFP in PA]

In January of 2010, I had the engine in my 05 997 S replaced for free by Porsche with a new engine due to severe scoring on the #6 cylinder wall (Thank You Porsche!), and am wondering if the new engine that was replaced should have any of these RMS/IMS failures?

I know it's a defect inherent in the 997.1 engine design (and 996 as well), but am hoping this defect has been worked around or resolved effectively with the new replacement engine.

Any replacement engine supplied by Porsche in 2010 would have the very latest RMS design, so you are fine there. The IMS would also be their last version design, which still has some level of potential to fail. It is also the design that cannot be replaced without disassembling the engine as it is too large to fit through the opening in the rear of the cases. But then you should have also gotten an additional two year warranty on the new engine..........

[coleta]

harperb, what did you originally bring your car in for? What were the symptoms?

[harperb]

harperb, what did you originally bring your car in for? What were the symptoms?

There was soot coming out of one of the tailpipes. Brought it in once and they looked at it and couldn't determine where it was coming from. So they cleaned the tailpipes and that was it. A couple of weeks later, the soot was back again. After bringing it in, they investigated for a fair amount of time, and eventually boroscoped the engine and found the scoring on the #6 cylinder.

After finding that, Porsche agreed to replace the engine for free with a brand new one; it was a CPO car recently out of warranty.

[coleta]

Thanks and Congratulations

[jroach]

Took the car in Weds and it was done Thurs. McKenna provided me a loaner (Panamera) and took care of everything! McKenna is several miles out of the way for me but it's worth the extra gas and time to get people who want to take care of you.

I didn't replace the clutch...it had plenty of life left and seemed like a waste of money to replace it three years sooner (or maybe more) than it should be. My contribution to being green (smile).

They did replace the seal for the Intermediate shaft on the transmission side as well as the RMS. Not certain if that was a normal procedure but my service manager said it wasn't unusual. We had talked about the IMS but didn't take any action to investigate...based on all the good input from this thread I didn't want to pursue something that is so hard to prove/find. I don't drive the car to extremes, it only has 25k miles, and those are pretty easy miles as well.

My remedy is to just get the 991 when it comes out (smile).

Thanks to all for the discussion!

[Hroussard]

I sold my 996 (1999) 6speed , 76k miles, a few months ago just because I did not want that engine (RMS - IMS etc) to explode ... or is it "implode" and cost me the better part of 15K just to get back on the road. I will tell you that this "threat" hanging over my head really took away much of the pleasure of owning the Porsche. I was lucky and I got away with it and that is really how I feel about it. However, I do like Porsche as a driving experience. So I have been looking for my next fun car. I have been reading all the Renntech (and other forums) discussions across 996/997 turbo and non-turbo engined cars, 2 and 4 wheel drive and frankly I do not see an improvement on the quality of the Porsche engines and increased / improved durability. I do not agree that a Porsche engine should be a "consumable" part that is expected to fail for which it's owner will have to foot the bill (after initial warranty). I expect that the engine and gearbox combination will be bullet proof and last as long or longer than a high output V6 or V8 from any manufacturer out there.

Some say the 997 later version(s) and turbo's do not longer have the issues but looking at the owners discussions and these cars only being a few years old, it looks like a case of "the other shoe is about to drop". It seems they are just as bad. Lifters go bad, water pumps, cooling systems, ignitions , coils. It's a list of bad things that keep on popping up over and over that the owner gets to deal with. Nowadays, a 3.8 liter car with just 350+ horses is an ordinary-run-of-the mill engine and not a fire breathing - leading edge technology power plant it once was. Input? Thoughts?? Suggestions?

[SA321]

i can agree with you on 996 and Cayenne. frustrating part is not that they break but the fact that many of these serious errors are known to the manufacturer and they have done nothing about it... I remember a similar company that was an unquestionable leader in its space but too arrogant to listen to anyone around - Nokia. Anyone has their phone nowadays?