As a technician for GM I have to do warranty engine work and while doing a job now (rebuilding a seized 6.2L) I have to replace the oil cooler lines due to metal contamination. This is on a 2022 Sierra. I found that there is a oil pressure/temperature sensor combined into one that's mounted to the oil cooler lines right where it meets the block.

Basic pin out is as follows. One for 5V reference, one for OP signal, One for ground, one for OT signal.

Would it be possible to wire this into an MS3? Share one 5V reference and then send each signal to the extra connector for additional inputs? Or will it require two separate 5V references to work right?

The sensor will need a threaded adapter to work in place of the factory Miata oil pressure unit but it's about 1/3 the size of it and probably far more accurate. If this is something that can work you'd get two sensors for the price of one.

I can post pictures of the wiring diagram from GM if needed for reference.

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You're looking for something like this. If you have the two spare inputs, then you can wire it into your MS3.

https://lowdoller-motorsports.com/co...00-f-pn-899404

 

This type of sensor only need one 5v and sensor ground reference. Then wire each signal to a spare input in the MS3. The Lowdoller is a steal of a deal for one of these.

 

This. I'm using a Bosch OP/OT sensor and have it wired like this into my MS3: one 5v reference, on GND and the signal going into the 'squirt.

 

I have the Bosch one in my two Miatae too- you also need a pull-up for the temp input so:

- 5V out of the MS to the sensor
- sensor ground out of the MS to the sensor
- oil pressure input (is already 0-5V) from the sensor to the MS
- oil temp input (with a pull-up from the 5V wire from the sensor to the MS

 

The sensor I grabbed was free off a set of oil cooler lines I'm swapping out. With the plentiful availability of these sensors on many new LT/LS engines from 2019+ models it wouldn't be hard to find one in the scrap yard for a few dollars.

What is nice about the Lowdoller one is that it already thread matches into the factory location and does not require an adapter.

 

Wish I knew these existed before I installed my separate sensors, much cleaner and one less oil failure point, cat. Should be easy for most MS installs to wire into two analog inputs.

 

The part number for the sensor I'm going to try to use is AC Delco # 12685371. Retails for around 30 dollars. I'll grab the connector part number for reference as well. It'll be a bit before I install this so if someone decides to try this before I do please update this and let us know.

 

Do you know the calibration for the pressure and temp on the AC Delco part? That would be the only obstacle to make it work well.

 

I will try to get that information as soon as I can. It's been busy at work. I'll have to call GM Techline. Or do you think I can find it's min/max values then interpolate the in between? I'm not sure if it's a linear sensor though.

 

Bumps.

 

I'm still working on trying to find the information related to sensor scaling. I'm going to have to call AC Delco directly and speak to their technical department.

 

Was looking into this but isn't the oil sender port in BP(&B6?) blocks 1/8 BSPT, not 1/8 NPT like the lowdoller motorsport sender ?
So it wouldn't seal properly in a bp block ?

 

That's correct; and adapter is needed. The same is true for the Bosch Motorsports option (need BSPT to M10x1.0). I bought mine from Ebay and it worked a treat.

 

Meh so there's no point / benefit in ordering the lowdoller one from the US. 😢

I guess a combined pressure / temperature sender with 1/8B BSPT thread doesn't exist?

 

I can't say for certain, but I wouldn't hold my breath. You may be able to find a sensor, but the trick is finding the right calibration data. From what I've seen online, those that have calibration are not BSPT.

 

So - after ditching the Bosch Temp/Pressure sensor because it's not supposed to be mounted to the block, and failing to use it with a remote sensor mount kit(temp readings are useless) I got me one of these lowdoller sensors. Mounted directly to the block via an 1/8 BSPT > NPT Adapter.

Now the builtin PT100 thermistor has a rather low resistance range (0-140°C = 100 - 150 Ohm). Using a 1000k Ohm pullup resistor I'm getting a rather narrow voltage range 0,45V - 0,67V in the expected temperature range of 0-140°C.
200 - 300 Ohm would seem ideal and give a range of 0,5V variance at the expected temperature range of 0-140°C.

Would that still be acceptable for a pullup resistor or is the expected 25mA to much for the ms3 Vref supply or ADC input ?

 

Ok, that is news to me- where do get that from?

Maybe it works for me, because they are mounted in the oil cooler adapter plates.... BAT motorsport has a nice one with integrated thermostat and 2 extra ports for sensors...

 

From Bosch / the manufacturer. It's specifically not intended to be mounted directly to the engine(vibrations) and also according to the datasheet has to be mounted upright or at worst at an 45° angle.
And there's lots of people on facebook / haltech group with these sensors starting to leak through the connector. I assume due to this.

See also the remarks from this vendor: https://stonemotorsport.com/products...ed-13aug_11-27

I'm aware there's a certain person out there selling speedyefi display kits for the miata including this sensor and a simple bspt>npt adapter. When I asked him directly he claimed that's not an issue but also admitted he had a "couple" of buyers reporting these failing or leaking.
I'm not risking that.

 

I have yet read of anyone who has spoken ill of Syltech for premium motorsport sensors, though it might be because they are a small company. They do offer an pressure and temperature combination sensor (MSCS).

Buy once, cry once.