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Yuba, I can't speak to your problem, perhaps by now you've figured it out and want to share what the root of issue was?
msmola2002, I'm wondering how the sensor has been doing with your sealing method. I'm eyeing a $45 cheapo version of this sensor on Aliexpress. I'm hoping that if the sensor leaks, it would tell me so with a low pressure warning
I have seen the similar Lowdoller-branded sensor posted recently with a 1/8" NPT thread, if adapting m10 doesn't work well maybe I'll have to go that route.
Yeah, so my issue was that KPower grounded the sensor to regular ground instead of sensor ground in their early K24 BRZ harnesses.
The next K24 I put together is getting a Syltech sensor for a few reasons:
1. Don't need to deal with the trapez plug
2. The Bosch seems to end up leaking eventually, sometimes explosively
3. 1/8" NPT instead of this weird M10 that requires an adapter, the adapter moves the temp portion out of the fluid stream making it somewhat less accurate
Yeah, so my issue was that KPower grounded the sensor to regular ground instead of sensor ground in their early K24 BRZ harnesses.
The next K24 I put together is getting a Syltech sensor for a few reasons:
1. Don't need to deal with the trapez plug
2. The Bosch seems to end up leaking eventually, sometimes explosively
3. 1/8" NPT instead of this weird M10 that requires an adapter, the adapter moves the temp portion out of the fluid stream making it somewhat less accurate
That's good to know. I suppose having a perfect fit and function the first time is worth at least $50.
Yeah, kind of annoying how expensive the Syltechs are but it is what it is.
Also, for what it is worth, I am running the Lowdoller pressure/temp sensors for my fuel temp / fuel pressure and coolant temp / coolant pressure. They work fine but I had to make my own resistance table for Haltech, I wish they had a lower temp range for better resolution.
Lowdoller 899404 Pressure & Temperature Combo 150 PSI / 500*F
5v / 1k pull up
No leaks here from where I screwed it in, but seeing a lot of failures in the Haltech group on FB. The thought of a knockoff of a part that may also be somewhat questionable, I would not do it.
Unfortunately my miata project will be winding down in the next year or two, to eventual sale or partout, so I'm not investing time on continued improvements.
The consensus in those Haltech circles is also the Syltech is the way to go. Can also be purchased from platinum racing products in oz, from just up the road from my home town. Wait til black friday and get some free shipping on that **** - I did that already for sensors I planned to use for coolant and fuel pressure. https://www.platinumracingproducts.c...ctions/syltech Bear in mind that is in Aussie pesos, so figure about 2/3 the price. If you wish to buy locally, there are some drift boiz down in Florida who sell Syltech already.
So I got me one of those Bosch Temp/Pressure sensors (0261230482) and an m10 > 1/8 bpst adapter from aliexpress to replace the oem oil pressure sender but now that I'm looking at them I'm a bit skeptical.
The tapered edge inside the female m10 port is slightly covering the pressure pinhole on the bosch sensor when fully threaded on.
That should not be a problem for pressure; however, I would be sceptical if you would get reasonable readings for temp. The probe needs to be in oil flow, stagnant oil temp measurement would not be the same as actual oil temps.
That should not be a problem for pressure; however, I would be sceptical if you would get reasonable readings for temp. The probe needs to be in oil flow, stagnant oil temp measurement would not be the same as actual oil temps.
Well there is no native 1/8 BSPT pressure temp combo sensor out there..
I've checked the aforementioned haltech groups and their feedback on these bosch sensors. There really are a multitude of reported leaks through the connector including lots of videos (although most of them showing fuel not oil)
Those who still claim the sensor is fine when used correctly are remote mounting it.
https://m.facebook.com/story.php/?story_fbid=3618825685003399&id=1766797626872890
So I've decided to also remote mount my sensor. Added bonus is also having an additional 1/8 BSPT port for the oem oil pressure switch and keeping the dash warning light intact.
Yes I realize this will most definitely cause lower temperature readings but if there's an oil leak I'd prefer it to have it in plain sight and easily capped / resolved.
So I got the sensor wired up to my ms3 basic and connected through the remote mount. Linear calibration, pressure seems to read fine and is giving me sensible readings: around 40 psi idle, up to 70 psi at revs.
After forgetting I needed a pullup resistor for the NTC thermistor it was rewired and it's pin also connected to the 5v Vref pin through a 2,4k ohm resistor. Value according to the other analog inputs on my ms3 basic which have an integrated 2,4k ohm pullup by jumper switch on the board (yeah should've just used those inputs).
Then used the custom thermistor calibration tool with 2,4k bias resistor in tunerstudio but the resulting readings are way off. Like less than half of where they should be according to my analog gauge feeding from a sensor in the oil pan.
Is there maybe an undocumented resistor in parallel on the board connected to pin adc6/JS5?
If I calibrate with a 1200 ohm(2 x 2,4ohm in parallel) bias resistor the readings are in the ballpark and almost make sense?
The 5 free analog inputs have individually selectable pullup resistors, which are 2490 ohms for all the analog inputs. There would be no sense in adding undocumented resistors in the spare analog inputs. Make sure you are using 3 datasets that have enough separation between them, otherwise the inverse Steinhart-Hart equation solution does not produce adequate results. I like to use 0C - 40C - 80C. Also note that higher pullups will favor resolution at lower temps. For oil temp where you are looking to have better resolution at 70-120C, its better to have a lower pullup in the 1K range.
The 5 free analog inputs have individually selectable pullup resistors, which are 2490 ohms for all the analog inputs. There would be no sense in adding undocumented resistors in the spare analog inputs. Make sure you are using 3 datasets that have enough separation between them, otherwise the inverse Steinhart-Hart equation solution does not produce adequate results. I like to use 0C - 40C - 80C. Also note that higher pullups will favor resolution at lower temps. For oil temp where you are looking to have better resolution at 70-120C, its better to have a lower pullup in the 1K range.
So every analog input does have the pullup resistor by jumper?
In the manual only SPARE_ADC and EGO2 have it mentioned. 😅
I assumed the other two (ADC6, ADC7) don't.
Thanks for the info, maybe I'll swap to a 1k resistor
*update*
I tried without a resistor to check if an internal pullup is somehow enabled by jumper - no readings.
Replacing with a 1k resistor pullup to Vref - same readings as before, only 20-40°C.
Then I got out my infrared thermometer and checked the sensor /fittings surface and got almost exactly the same readings as in tunerstudio / msdroid.
Welp.
I guess it's back to the drawing board. This remote mount is fine for pressure but the temperature drop through the braided line and adapter block is seemingly massive.
Tl:dr
Forget this bosch motorsport sensor for a miata. They're explicitly not built to be mounted directly on the engine or they will fail and/or leak.
They also have to be mounted vertically pointing downwards or at a max. 45° angle according to bosch. Hard or impossible to do when mounted near the engine to get better readings.
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