Eliminate the oil level senser

[obthomas]

Does anyone know how to eliminate the Porsche oil level sensor and thereby stop the cluster from messaging. 2003 Boxster S.

Thanks

[paulofto]

Just one question. Why?

[Starter986]

Originally Posted by paulofto

Just one question. Why?

That's the exact same question I had yesterday morning at 3A. I didn't pose it at that time cause, ya know... 3A. It wouldn't have turned out nice.

[obthomas]

It might be easier and cleaner than adding a Porsche level sensor to the LS3

[78F350]

So, this engine?


It looks like the sensor is wired to the cluster directly, at least on the early models. I expect that the sensor works by increasing/decreasing resistance across pin 2- GN/BL wire "oil level" and pin 4- BR/OR wire "analog ground" (Pin 1 and 3 are for oil temperature).

I'd test that theory by measuring resistance between those pins while the sensor is immersed in varying levels of oil. If that's the case, I'd put a dummy resistor in place of the sensor to simulate a 'good' level.

[obthomas]

Yes it is! Great answer. For the moment I do not have the sensor, let it go with the Porsche engine when it sold. I shorted the same wires and still got a failure message. I was thinking to buy a sensor and do exactly what you say. My 2003 is a bit more challenge than an earlier car because some of the works is through CAN. My coolant temperature for example is a 2 wire resistive circuit to the ECU. For the life of me I couldn't see how the cluster gage picked up the temperature. Heated the sensor and the cluster Gage works. Has to be over CAN. On to the next challenge. Any Ideas for the tachometer? It appears to be CAN

[78F350]

I just checked the diagram for the '03 and the wiring for the oil level is the same as early cars. Pretty sure you are correct about the tach signal on CAN.
I have a recently removed (bad) engine that I can test the sensor on when I get time. May be a few days....

[obthomas]

78F350

Thanks for the testing offer. I will wait your results. Meanwhile can I get your thoughts on another challenge?

The cluster is acting fairly normal with key on. Most everything seems to work, even the tach zeroes. However, all of the signal (idiot) lights turn on as expected but then stay on. The cluster seems to be waiting a signal to proceed. I have looked at an engine run signal and can't find one so it is still a mystery to me why the cluster won't go one more step and extinguish the idiot lights. Worst case it could be another CAN issue. My ME7 is still active and maybe It needs to see something to send a CAN signal. Any thoughts are appreciated. Two heads are better than one. Thanks

[obthomas]

got the cluster working.

[78F350]

Originally Posted by obthomas

got the cluster working.

Did you figure out what makes the idiot lights go out? I'm traveling this weekend and plan to test the oil level sensor Tuesday evening or Wednesday.
Rocking in Charlotte NC right now on a long lay-over.

[obthomas]

Yes. The idiot lights go out when the alternator connection goes positive, and the low oil pressure switch is open. In other words when the engine is running.

Really good news if it is true. I found out that the Boxster and LS3 have the same reluctor count. I am assured that if I tee the #45 pin white wire (engine speed) at the Porsche ME7.8 52 pin connector into the LS crank position sensor high that my tachometer will work.

Few more days of miscellaneous and I will be ready to start the engine. Need to pull the valve covers and torque the rocker arms, all loose while the engine was sitting for a long time. Need to prime the oil system and waiting on a couple of coolant fittings and one gas fitting.

Thanks for asking and for your help
O.B.

[78F350]

I did a simple test with a cheap multimeter and some wires with alligator clips. I dipped the sensor in a bottle of oil that was filled to the depth that the sensor was immersed in the engine. My results were not precise, but did show a trend.

• A 'good' oil level showed around 15 mega Ohms resistance.
• High oil level got up to 19 mega Ohms
• With the sensor pulled out of the oil and wiped, it showed 8 - 10 mega Ohms

I may take the experiment a little further when I have time. I don't expect to find a 15 M Ohm resistor in my parts pile, but I may find some that I can put together in series to see what happens either connected to the sensor connector or directly to the cluster and ground.

If my readings and guesses are correct, you could solder three of these 4.7 M Ohms together in serial and connect it to pins 2 and 4 of the connector and get an acceptable oil level indication. (eBay) I could easily be wrong.

[obthomas]

Originally Posted by 78F350

I did a simple test with a cheap multimeter and some wires with alligator clips. I dipped the sensor in a bottle of oil that was filled to the depth that the sensor was immersed in the engine. My results were not precise, but did show a trend.

• A 'good' oil level showed around 15 mega Ohms resistance.
• High oil level got up to 19 mega Ohms
• With the sensor pulled out of the oil and wiped, it showed 8 - 10 mega Ohms

I may take the experiment a little further when I have time. I don't expect to find a 15 M Ohm resistor in my parts pile, but I may find some that I can put together in series to see what happens either connected to the sensor connector or directly to the cluster and ground.

If my readings and guesses are correct, you could solder three of these 4.7 M Ohms together in serial and connect it to pins 2 and 4 of the connector and get an acceptable oil level indication. (eBay) I could easily be wrong.

Outstanding it sounds like you could be right also. I have several more items to button up before I start the engine and I also have to make a trip this weekend so I won't be back to you for a while. gives me time to order the resistors. Thanks for the help.

[obthomas]

[QUOTE=78F350;648950]I did a simple test with a cheap multimeter and some wires with alligator clips. I dipped the sensor in a bottle of oil that was filled to the depth that the sensor was immersed in the engine. My results were not precise, but did show a trend.

• A 'good' oil level showed around 15 mega Ohms resistance.
• High oil level got up to 19 mega Ohms
• With the sensor pulled out of the oil and wiped, it showed 8 - 10 mega Ohms

I may take the experiment a little further when I have time. I don't expect to find a 15 M Ohm resistor in my parts pile, but I may find some that I can put together in series to see what happens either connected to the sensor connector or directly to the cluster and ground.

78F350

The resistance thing didn't work. I finally found the test for a good sender in the repair manual and it compares with your test except it says look for 15.4 K Ohms. I cobbled together both the 15 M Ohms and the 14.7 K Ohms and neither worked. Because it is 2 wire and also transmits oil temperature, I think it is more a transmitter.

At any rate I bought one that will arrive any day. May have to put it in a mason jar of oil in the trunk to keep the cluster quiet.

[obthomas]

I can close this thread out. I got my used oil level sensor and discovered it is actually two sensors in one. The oil level sensor operates as a resistor around 7 to 10 ohms. Until now we must have been experimenting and focused on the temperature sensor. The instrument cluster is fooled with a 7 to 10 ohm resistor.

[78F350]

That's awesome. I may have got my pins mixed up between the harness side and the sensor side. Glad you got it worked out.

[peterklein454]

Interested


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[peterklein454]

Originally Posted by Starter986

That's the exact same question I had yesterday morning at 3A. I didn't pose it at that time cause, ya know... 3A. It wouldn't have turned out nice.

Interesting


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