Does anyone have the technical specifications on the OEM oil temperature and pressure senders? I am looking for the resistance vs temperature table for the temp sender. Also is the pressure sender an analog 0-5VDC output, a variable resistor dependent on an external conditioner (and if so what is the range of resistance and pressure) or is it simply a switch for the idiot light? I intend to send the analog signals directly to the Dashdaq.

I tried to tap the drain plug for 1/8 NPT but making threads deep enough to take the sensor leaves too little wall thickness on the original plug. When I screwed the plug into the pan the shaft actually broke off into the oil pan which I managed to get out after a moment's panic. I was about to retap the oil pan itself but am considering using the OEM sensors themselves or if necessary replacing them with sensors for which I already have the Steinhart-Hart equations.

 

The stock oil pressure sensor is just a switch for the warning light.

GTM uses an oil distribution block adapter on the stock oil pressure sensor tap to monitor several parameters from the same location. They use HKS sensors from the Camp 2, but you can use the same adapter for your own equipment. It's quite expensive for what it is so you may be able to fabricate your own or find something similar in a hardware store.

GTM Motorsports ENGINE EXTERNALS OIL SENDER ADAPTER KIT

 

I'm using the same thing in that picture. It works great! Oil pressure reads

 

BTW, were you tapping the drain plug for oil pressure sender? I think you need the oil filter location pictured above to read oil pressure correctly.

 

Thanks for the tip about the GTM adapter. I saw that adapter earlier in previous threads and was about to fabricate one but I don't think I need the adapter and would just rather replace the existing oil sender.

Here's my understanding: the stock oil pressure sender activates the light when I ground the signal so the idiot light only trips when the circuit is complete. Removal of the stock sender should therefore not show a low pressure light. I intend to replace the stock sender with a true sensor and record the analog out to a virtual gauge (Dashdaq). If it is necessary to maintain the idiot light functionalitity I can instead use as dual station sender to maintain continuity to the ECU.

Thoughts?

The temperature sender is a more tricky issue. Other than soft engine shutdown at high temps I haven't been able to determine if the ECU simply trips at a set temp or if the ECU needs to read a range of temps which affect valve/cam timing, etc.

Edit:

No. I tapped the drain plug for the temp sender. I had the oil pressure sender on a sandwich plate but I will be replacing that with a thermostat for the oil cooler.

 

Disconnecting the stock pressure sender will probably throw a code, you can get a T fitting for a couple bucks from most hardware stores anyway. The aftermarket stuff has multiple taps for turbo oil feed/return lines which you don't really need. Anyhow, I'm not quite sure about the factory temp sensor TBH :/

 

Thanks for the info. I'll experiment with a T-fitting vs dual station sender.

I see you have a cooler. How are you monitoring your oil temps?

 

My cooler is actually for the transmission. I have a 5AT G35 HR, so I don't have the same oil temp issues as you guys. Anyhow, depending on your data reading system, you can read the factory oil temp sensor from the OBDII which is fairly accurate.

 

Ah, I did not know that the oil temp signal was available via the OBDII. I have ECT but not oil. I will recheck.

 

I ended up unplugging the stock harness to the oil temp sensor and attached my own harness to the stock oil temp sender. My harness leads to a data logger with a pull up resistor. I can now record oil temps off the original sender. My running temps are ~180 during regular driving going up to ~220 during track although this is with cool ambient temps and run times ~30 min. I may have to install an oil cooler for longer runs during warmer days.

I extrapolated the resistance vs temperature curve after doing a bit of testing but would like to find the specific table or equation for curve of the stock sender. If anyone has the information or can provide the specific model number of the sender, that would be helpful. Or even the dimensions of the sender (thread, etc) would be useful. Then I would replace the stock sender with one of the same size but with known resistance vs temp that I could enter into the data logger.

For the oil pressure I replaced the stock sensor which is indeed just a switch with an analog 0-5V oil pressure sender (part number ATM-2246). The original harness is left unconnected. No codes thrown. I ended up not needing the GTM adapter. I am monitoring oil pressure in real time.

Thanks for all the help.

 

I think youre going to get a CEL sooner or later.

 

No CEL thus far. I am not sure how I would get a CEL. The sender is just a switch, not a gauge. A disconnected switch would show the same thing as a connected switch with adequate pressure: an open/high resistance circuit. The inherent flaw with just using a switch is that there is no failsafe in the event of disconnection or faulty sender; the light would never come on.

Another way of looking at this is to examine how testing is done to diagnose a low oil pressure warning light/CEL given adequate oil levels and pressure in the system. If the low oil pressure light/CEL is ON one first disconnects the sender and the light/CEL should CLEAR unless there is short in the circuit. To test if the problem is in the instrumentation one then shorts the sender wires or grounds the wire and the light should come back ON.