MOXY_997.2

My son and I were out driving my 2010 997.2 two last week. Oil pressure on the gauge was running 2.5 to 3.0 on the gauge while driving. When came to a stop at a light and the pressure on the gauge went to "0" and a warning came up that said something like, "Oil Pressure Monitoring System defective - malfunction". We pulled to the side of the road (pressure went back to normal) and shut the car off. The next day we took it to a local indy and they worked with the oil sending unit harness, problem still present. They then replaced the oil sending unit and the problem is still present. They are going to look into taking a manual pressure tomorrow to see if the pressure is actually dropping.

Has anyone here ever heard of a problem like this one? Thanks in advance for any suggestions?

Petza914

I believe the 997.2 has a variable oil pressure pump, vs the fixed style in the 997.1. Wayne Smith knows more about how the .2 one works, I'm not sure what it uses for criteria to make it vary the pressure, but could be a sensor related to that could have gone bad. Obviously you don't want to drive a car that's not making any oil pressure and not knowing if the gauge, sender, or pump might be the culprit, don't start it again until that's determined.

TheBruce

Hmm. Yea that's one you definitely dont want to mess around with until its solved. Does it only drop when idling? What was your oil temp? I dont have any experience with the .2 so take my comments as a reference point only. I wrote a post a while back asking for guys to share their oil pressures and some of the .2 guys chimed in. I will try to find it.

On the .1 2.5 bars would also on the low-end while driving, unless you're puttering around. Im usually at 4-5 bars but I have a 6sp and tend to stay in the fun zone most of the time. The .1 manual says you should be >3.5 bar at 5k rpm. It doesn't give an recommendation for idling. When my car is cold it idles at 5 bar then will drop to around 2-3 once its warmed up a bit. If im getting on it and my oil temp is 210-220 it will idle at 1 bar.

Hopefully its just something with the sender. Given the CEL, it seems to point that way. Hopefully some of the pros can comment on other areas to look at. I would assume the next item on the list is the oil pump.

If its ends up being something mechanical I would have them change the oil, check the filter and scope the bores...but I tend to be neurotic.

Wayne Smith

Edit ... Sorry, just reread your post and realized your car didn't auto heal (replaced sender and problem still exists). I now assume you flat bedded the car to the dealer. I'd worry about number 4 on the list below. Anyway, the following is my unedited initial post that assumed you drove the car home without mechanical failure ...

The 997.2 has scavenger pumps at each corner of the oil pan. These pumps supply oil to an internal chamber that contains another pump. The chamber pump supplies an outlet unit that contains multiple proportional control valves. The valves automatically adjust pressure individually to various parts of the motor based upon operating conditions ... Computer controlled.

So there is no single oil pressure on a 997.2.

I can't tell you what the oil pressure gauge indicates on these cars. From what I've experienced it's kind of a dummy system (like the water temperature gauge that always reads 175F).

Going to 0 would, IMHO, represent one of the following ...

1. The internal chamber (I'm referring to it this way rather than a sump because some will state that a sump system must be external to the motor) went dry. Thus all pressure stopped. The oil would need to be incredibly low for this to occur.

2. The chamber pump failed. It is unlikely it would auto recover.

3. All four scavenger pumps failed. I'm not a big believer in two simultaneous failures let alone four.

4. The proportional control unit stopped operating. It is unlikely it would auto recover.

5. The pressure sender (from whatever part of the oiling system that is attached to) failed. Again, not likely to recover.

6. A connection to or from the sensor failed. This could Auto recover. Note: There is no such thing as a good connection!!! Connections go bad and self heal. They are very possibly the biggest problem in electrical systems (bad connections not only cause systems to stop operating but can also cause spikes that damage good components).

7. The computer glitched and required a reset.

I'm voting for number 7, but there may be others. Keep us updated.

Iceter

Wayne, that's fascinating information. Thank you for the explanation.

Do you know where the gauge pressure is measured? With multiple pressures coming off of the proportoning valves (and the resulting multiple failure points) I'm really curious about where a relevant pressure could be measured.

MOXY_997.2

The indy in my area spent a week working on this problem. They were trying to work through all the low cost, easy to get to options first. First, they manually measured the oil pressure and compared it to the gauge. The readings were similar (oil pressure was running on the lower end of acceptable while at idle). Next, they worked with the sending unit connections without any improvement in the oil pressure. The decision was then made to replace the "main" oil pump. Once the oil pump was changed and the car started the pressure returned to normal. Whew, a few dollars less in my pocket, but the care is running normally.

Thanks to Stuttgart Specialists in Louisville, KY. Great group, they kept me informed, gave me options and were just a nice group to work with on this issue.

Wayne Smith

My guess, and it's only a guess, is that they are measuring pressure going into the multi output port. Normally in industrial equipment you need multiple pumps to control multiple pressures. The Press and Technical releases when the 997.2 came out left a lot of voids IMHO.

swingwing

Here are some excerpts from Service Information, 2009 Technik Information. This book's part number is PNA 911 021 09.

Oil Supply (p.19)
"...The main differences between the new oil supply system and that used on previous models are as follows:
* Additional oil extraction point in the cylinder head
* Electronic demand-controlled oil pump
* Additional watertight sheetmetal pan between crankcase and oil pan"

Demand-controlled oil pump (p.21)
"In order to reduce drive losses from auxiliary units and improve efficiency of the engine, while at the same time reducing fuel consumption, the new 911 Carrera models are fitted with an electronic demand-controlled oil pump.
With this new pump, the delivery pressure and volume is controlled for the entire engine map. In other words: the required oil pressure and a defined oil volume is set for each engine operating state (e.g. different engine speed and load). The oil pump is integrated neatly in the oil pan area and is driven directly by the crankshaft via a chain."

While driving my '09 the last year and a half, I see oil pressure about 2.5-3 bar after the oil is warm. I doubt I've ever exceeded 6k rpm. Engine runs great and the one oil analysis I've done at 40k miles shows no issue with wear metals.

Jesus Medrano

Have same problem with my 997.2 already change oil preassue sensor and verify the harness and the problem still there

Petza914

I believe the 997.2 has some type of variable oil pump. I don't know what makes it variable or controls the variability, but maybe it's a problem with that control module.

liteuser

interesting read,
i have an oil pressure issue between 2500rpm to 3500 rpm at cruising speed it’s on the ramps at the moment awaiting a new variable oil pressure sensor, I’ll let you know if makes a difference.