Oil pressure sender + "smarter" idiot light mod

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Finally got around to installing an electronic pressure sender. Little bit of an endeavor on this car that requires taking off the intake to access the front of the block. Also took the opportunity to inspect intake valves, as well as the PCV hoses and oil separator. See this thread for that discussion: https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4802182/1



Because I didn't want to add more points of failure or leaks by using a T fitting, I completely removed the factory oil pressure switch. It was the classic idiot light switch set for around 6 to 8 psi. If the warning light ever illuminated while driving, the engine would already be dead. Sensor threads were M14x1.5, requiring use of an adapter to fit the sensor's 1/8 NPT threads. I used a high temperature thread sealant suitable for exposure to hot oil.



Because I ran the sensor through my Arduino data logger and gauge screen, I could make a little circuit to allow the Arduino to switch the oil pressure warning light. I used two setpoints, with a steady light to indicate oil pressure caution and flashing light to indicate oil pressure warning.



Once I had everything back together, I found some very encouraging signs when I started it back up. Oil pressure comes up very quickly - by the time the engine fires pressure was already climbing past 40 psi. 84 psi of oil pressure at cold idle, and 22 psi at hot idle in gear with oil temp at 100C / 212F. Minimum spec for hot idle at 100 C is apparently 14 psi on this engine. By 2000 rpm, oil pressure is around 40 psi, and nearly 70 psi by 3000 rpm. Minimum spec at 4000 rpm is 50 psi. Overall looks like pump and bearing clearances are quite healthy. Data log graphs coming soon when I have time to process them.

I think I'll set the caution to illuminate at 20 psi and the warning flash at 15 psi. At least will give the engine a fighting chance if there's a sudden leak on the highway and I somehow fail to keep track of the number on the gauge dropping.

Vacuum is low in this pic because engine is cold and the AC is on. Warm engine in neutral without AC shows around 21 inHg.

 
Originally Posted By: zorobabel
Nice. Is the oil filter mounted with the threads up? How many seconds does your car crank before firing up?


Filter installs threads up. This shouldn't make a difference other than first start after an oil change or a failure of the ADV. If I recall correctly, the idiot light would stay on for maybe a couple seconds for the first start after changing oil and filter.

Car starts up extremely quick. Three ish compression strokes and two injector batch fires before it catches. Maybe four or five compression strokes and another injector pulse at 0F / -18C . Big group 48 / H6 battery and a large starter for a 2.4L inline 5 with 9:1 compression. Hilarious thing is the manual states up to 10 seconds of cranking is "normal". No idea what torturous combination of arctic cold, unprimed fuel system, and failing battery would ever require that much cranking.
 
Thanks, that explains it (filter with threads up). Filters with threads down or to the side - could have the oil drain from the clean side even with a working ADBV.
 
Originally Posted By: Colt45ws
Is that sketch for that gauge screen somewhere? Thats pretty much what I am looking for.


This sketch is 100% my own creation, and of course a constant work in progress as I add new features and hardware. The original parts of the program were started in early 2015 and I've slowly expanded it ever since. Currently it controls my airhorn system (original purpose), two-stage cooling fan outputs with setpoints for oil temp and transmission temp, data logging to an SD card, and of course the 16x2 LCD screen with context-sensitive buttons for adjusting values.

I'll need some time to clean things up but I could try to make it available someplace like Github. With all the above features, it requires a Mega to provide enough pins and RAM, and takes over 25k of flash so is almost too big to even load on something like an Uno. Code still runs pretty snappy with a full loop in 4 mSec, specifically written without wasting any clock cycles with delays. Trimming off unneeded features may let it fit an Uno but if you're the kind of person who likes to tinker you'll quickly run out of IO pins. Shaving off the menus and buttons can slim down the code a lot, but will require many things to be hardcoded. That kind of annoyance is why I went to such lengths to make the menus in the first place.
 
Originally Posted By: zorobabel
Thanks, that explains it (filter with threads up). Filters with threads down or to the side - could have the oil drain from the clean side even with a working ADBV.


Interesting. I'd think that would be a significant flaw with the design of both engine and filter if the filter orientation defeated the valve and let oil siphon back.
 
I'd go a different way-- flashing oil light if the engine's been running, solid-steady light if it was just started or is idling. You know the i/o pins you'd need for this to work, maybe flashing if there's MPH/ higher RPM/ coolant temp etc.
 
Please note that I'm only talking about the clean side of the filter.
I had a 99 Camry with the 4 banger and it had the filter mounted threads down. You'll often hear people complaining about how messy it is to change that filter, but if you let the car sit for 30 minutes, most of the oil from the clean side drains and no mess is made. That must be the reason it was specced with a teacup size oil filter.

Originally Posted By: VeryNoisyPoet
Originally Posted By: zorobabel
Thanks, that explains it (filter with threads up). Filters with threads down or to the side - could have the oil drain from the clean side even with a working ADBV.


Interesting. I'd think that would be a significant flaw with the design of both engine and filter if the filter orientation defeated the valve and let oil siphon back.
 
Originally Posted By: eljefino
I'd go a different way-- flashing oil light if the engine's been running, solid-steady light if it was just started or is idling. You know the i/o pins you'd need for this to work, maybe flashing if there's MPH/ higher RPM/ coolant temp etc.


I get what you're saying here. Flashing light to get my attention at the caution pressure, and steady light for when things have gone really south or the engine is stopped.

I don't have an RPM input yet but that would be a great idea for the smartest idiot light based on current pressure and RPM, since there are published specs and I could draw up a curve for that relationship. Maybe someday I'll be able to get that feature installed, though I'm the kind of person who frequently scans gauges so the light is more of a fun feature than strictly necessary.
 
Originally Posted By: zorobabel
Please note that I'm only talking about the clean side of the filter.
I had a 99 Camry with the 4 banger and it had the filter mounted threads down. You'll often hear people complaining about how messy it is to change that filter, but if you let the car sit for 30 minutes, most of the oil from the clean side drains and no mess is made. That must be the reason it was specced with a teacup size oil filter.

Originally Posted By: VeryNoisyPoet
Originally Posted By: zorobabel
Thanks, that explains it (filter with threads up). Filters with threads down or to the side - could have the oil drain from the clean side even with a working ADBV.


Interesting. I'd think that would be a significant flaw with the design of both engine and filter if the filter orientation defeated the valve and let oil siphon back.


That's a cool anecdote. Did the car make any angry noises or have the oil light linger when it started after sitting a while?
 
No startup noise with Purolator One filters I was using; I didn't pay that much attention to the oil pressure light back then (other than make sure it goes away).

Originally Posted By: VeryNoisyPoet

That's a cool anecdote. Did the car make any angry noises or have the oil light linger when it started after sitting a while?
 
Originally Posted By: VeryNoisyPoet
Originally Posted By: Colt45ws
Is that sketch for that gauge screen somewhere? Thats pretty much what I am looking for.


This sketch is 100% my own creation, and of course a constant work in progress as I add new features and hardware. The original parts of the program were started in early 2015 and I've slowly expanded it ever since. Currently it controls my airhorn system (original purpose), two-stage cooling fan outputs with setpoints for oil temp and transmission temp, data logging to an SD card, and of course the 16x2 LCD screen with context-sensitive buttons for adjusting values.

I'll need some time to clean things up but I could try to make it available someplace like Github. With all the above features, it requires a Mega to provide enough pins and RAM, and takes over 25k of flash so is almost too big to even load on something like an Uno. Code still runs pretty snappy with a full loop in 4 mSec, specifically written without wasting any clock cycles with delays. Trimming off unneeded features may let it fit an Uno but if you're the kind of person who likes to tinker you'll quickly run out of IO pins. Shaving off the menus and buttons can slim down the code a lot, but will require many things to be hardcoded. That kind of annoyance is why I went to such lengths to make the menus in the first place.




Oh cool! Yeah, I dont think its a problem if I have to get a different board to run it. Not like they are expensive. And yeah, I was basically looking at doing the exact thing you are doing here, with menus like you said.
Actually plan on also having mine do some accessory timing. Like keepalive modern cars have for the radios and windows. 10 minutes on those, shutting off when the door is opened, and 1 hour for my 2 way radios, staying on with some voltage monitoring for cutoff if the battery starts to go flat/or if I select it in the menu I want it to pull on my remote start module, and basically trigger a remote start cycle to recharge the battery. This way I can have a mobile repeater or a inverter running with the engine off and the Arudino will make sure the battery doesnt go dead. I probably should put a fuel level input too so it wont run the tank dry of fuel. If the low fuel light comes on, suspend autostart, and cutoff the accessories when the battery ends up going too low.
 
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