teknics

meh poor typing. The PCM assumes specific pressures at the OMP based on when and how long the OMP switch is closed/open as well as the "step" position of the motor (using the step position sensor ). These assumed pressures are built-in based on repeatability of the system when being designed. They monitor the pressure they have at the OMP while designing the system with external sensors and based on this data assume a standard pressure seen at the pump during specific positions of the stepper motor and other engine control factors.

You honestly think the PCM doesn't at least think it knows the pressures at which a key element operates, or have the ability to determine what effects on pressure (and all other measurements) changes in the system will cause? That's all the PCM is, a whole bunch of algorithms and complex equations. Expected OMP pressure based on pre-programmed reference/variables is a simple math problem for the PCM. Also you can imagine how much work goes into the OMP, it has to operate the exact same on all motors at all times, thats not easily achieved. So considering the amount of work i'm sure the first thing they do is determine and achieve the exact pressure they want and they make it happen everytime before they proceed.

(edit: added to clarify more, seems like rambling but it adds up)
Also a failure in the system which would be used to make these calculations (aka the stepper motor dying) results in limp-mode on purpose.
Limp mod results in the PCM putting the control pin to the minimum position and then bases the calculations solely off engine RPM. The minimum step position + RPM = the most basic OMP "scheduling". The rod-controlled s4 FC's OMP basically assumed RPM via throttle position, it was a rough formula, hard to do complicated formulas mechanically.

So if the car reacts so suddenly to a failure of the OMP you can assume the math of the OMP is critical, because since part of the system is bad it ignores EVERYTHING, anything that does that is considered critical. The only math required for the OMP is line pressure, since as i said the opening and closing of the system/injectors is completely based on line pressure at the check valve. So in a roundabout way hopefully i've demonstrated to you the point that the PCM always knows OMP pressure, when it feels OMP pressure isn't going to be what it wants it essentially kills the drivability of the vehicle.

(end edit)

The reason the car "limps" is because the PCM tells the car "with this much OMP working at this RPM i need this much pressure (it uses pressure to open and close the injectors therefore the OMP's basic function is pressure control)" The reason the car limps is because when the PCM determines it needs MORE then what it can deliver at minimum step it restricts fuel which stops rpm from increasing effectively.

Mazda knows before you can fully develop the rotary motor you still have to figure out the oil-ing/OMP system first. That's why every major OMP revision generally is followed by a new, better mazda rotary motor. (new pump setup on the 09 13b's....16x development and design....)

kevin.

dannobre

iTrader: (3)

Sounds nice...but take one apart and look at it...it is a very simple no pressure feed pump.....with basically a drip type output. When the pump expels oil...it drips out the nozzles.

I'm sure Mazda has an idea of the output "pressures" but the ECU sure as hell doesn't

GeorgeH

iTrader: (2)

I think what Kevin is saying is that the algorithms & data in the ECU are encoded with knowledge of how much oil is flowing and/or needed for any given operating condition, even if there isn't a sensor reporting pressure or flow rate.

Hope I got that right. Any way, thanks for the description, it was educational and I appreciate the thourough reply. And yes, I have been wondering if the viscosity of the oil one chooses has an impact on the amount of oil injected (or dripped LOL) into the engine for any given operating condition.

dannobre

iTrader: (3)

ECU know what "step" it wants for a given data point........The reality is that it has no way of knowing if the oil is actually being injected

It does know that the stepper motor moves......that's basically it

teknics

i know the OMP system. No need to explain it's deficiencies, I'm possibly the most anti-OMP person you'll ever meet. Credits due where credits due to mazda since the OMP is what makes the rotary consumer-ready.

But i assure you the PCM *knows* the expected pressure. Technically it doesn't know a specific number, but it doesnt need to. It understands when there is high or low pressure at the OMP, and that's all it needs to know.

a check valve operated system uses pressure, so it cant be a no pressure system. there are no wires at the injectors, they open only because of internal pressure.

designed to prevent other pressures from effecting the internal pressures of the inlet (because the PCM is operating on fixed known pressure values, those pressures are kept fixed).

the 09 oil injectors have certainly improved, about fuggin time. the injector is the peg leg (attachment)

kevin.

dannobre

iTrader: (3)

I hate to disagree Kevin..but there is no way the PCM can tell what is happening at the OMP...other than the motor is working. There are no pressure transducers...and the only pressure that is in the system is from the mass flow of the oil from the mechanical piston type pump. It injects an amount of oil based on the amount of movement of the pistons needles..that instantaneously pressurizes the output lines till it overcomes the check valves...So basically the system pressure is based on the function of the oil injection valves

PSTNLSS

iTrader: (3)

I'm so confused. I hope I can go out tomorrow morning, turn the key and just go wow that was easy.

teknics

agreed, but it assumes constants, and i agree that the idea of constants in an equation being bad. But even with it considering certain constants it still *knows* them, it isnt simply flying blind with the most critical system of the motor.

GeorgeH: yea that's about the jist of it. It does not know the *current* info that a sensor would know, but it uses multiple other sensors to decipher the situation of specific things that are required to calculate the pressure at the OMP. They choose to keep the mechanical design of the OMP simply, attempting to install an actual equal per port pressure sensing system would make the OMP overbearing and somewhat overengineered. Instead they find out everything that effects the pressure at the OMP, they then use all THAT info to calculate the pressure at the OMP and they fill in the blanks by following patterns, this info is all stored in the PCM in one way or another. Basically OMP Pressure is used in the internal calculations of the PCM.

i think you helped me figure out how to clarify my position, much obliged.

kevin.

dannobre

iTrader: (3)

Show me something that backs this up.....otherwise it's conjecture

This is an electrically controlled stepper motor...that is otherwise totally mechanical in function

There is no voodoo circuit in there....

The ECU expect certain outputs...but has no actual way to tell if the oil is coming out

teknics

exactly but the PCM knows how much pressure and volume that the mechanical piston pump can produce and move. It knows the amount of movement of the needles.

Not because of sensors monitoring it but because the system was designed to operate at constants. These constant can be determined using outside sources. The internal electronics, pressures and volumes of the OMP can be monitored during design. They can determine the voltages and other factors which result in the production of both the needles moving and the pump, basically the "plungers". During design they use the exact oil that they recommend and sell as mazda branded, they obviously don't *make* the oil, but thats the reason it's the "recommended" oil, all mechanical measurements have been made using that oil or at least oil that is fairly identical in specific categories. The oils are scientifically tested, proven, and certified so they know it is a constant as well.

Basically the PCM knows everything that mazda learned in a lab, it just doesnt need to learn it during real world operation because mazda already has told it what will be happening. All i am saying is the PCM *knows* the pressure, it may not physically *determine* the pressure at a specific time, but it knows what it *should* be, it's not responsible for failures in other parts of the motor such as lack of oil flow etc. In a situation like that the OMP would be the effect of another cause rather then being the caused of the problem itself.

(edit after i saw your reply above: yes i agree it doesnt know if oil is coming out, but *thats* not its job. Having a properly running engine, proper oil and proper oil level is ALWAYS assumed in engine design. If any of the 3 things is not good then none of the reliant systems operate properly, hell the seals siezing is a seal failure but is it the seals fault or the lack of oil? As for a "voodoo circuit" it's not a circuit, its programmed in information, code, 0's and 1's, the information is built into the mathematical equations, the proof is in the factor that the PCM uses ECT, MAF and RPM signals to determine the OMP output, that means there is a formula to determine OMP output, a formula has a solution and the solution is the pressure output at the OMP)

also as a note i believe we are disagreeing in misunderstanding, what you are saying is the basic form of my argument. the "ecu expecting certain outputs" is true but it also "uses specific inputs to calculate and control what is being output". The formula for the I/O involved requires knowledge of the pressures at the OMP, the PCM does this conversion of I/O so it *must* have the knowledge of pressure (based on sensors (ect, maf, rpm) and specific pre-programmed constants,tested and proven in a lab), under good engine running, good oil, and good oil level conditions...as these conditions are *always* assumed in calculations. see my above talk.

kevin.

kevin.

dannobre

iTrader: (3)

All it knows it what is "should" see based on "step" position on the pump......In a fully functional pump...that will result in a set output from the pump

No way to tell for sure though.....

The good thing is the pump is stupid simple..and doesn't likely fail often in a mode the position sensor wouldn't pick up

Easy_E1

iTrader: (2)

Not to change the subject but are these filters (in Red) in the prior to 2009 OMP Injectors, and where is the oil coming from through the system? Is it post oil flter?
And what is going to keep them from clogging up after many miles of use and diminishing the oil flow through them?

dannobre

iTrader: (3)

Don't see a filter in the older engines........

Looks like a total redesign of the nozzles..also doesn't seem to be an air balancing system on the nozzles like the old ones..

teknics

see my post on the previous page. From the information I have these filters were present in no other oil injectors. Mazda is improving the oil injectors for the first time. The filter i'm assuming to be metal mesh, haven't got the data on them yet. I was saying in a previous post that this seems dangerous to me, the chance of that filter clogged in my opinion is low but if it does it would drastically change the OMP injection system even if the whole rest of the engine is operating normally even the OMP mechanical unit itself. I also am assuming that the only way the clogged injector would be noticed is if the specific OMP has all it's injectors clogged as i would imagine that may be able to short the unit cause to such a pressure that the plunger system cannot moving cause the motor to continually try to open it results in a blown circuit, but that is definitely just conjecture. I've only really started cracking open the '09s real technical info just recently.

The first thing I looked for was oil flow in the system luckily i grabbed an image to use for an example (i was planning on making a topic but this one seemed to fit) The oil does in fact pass thru the oil filter first (unless bypassed internally), altho it goes a short distance from the filter (im guessing thats part of the reason for oil filter movement to front cover). See the attachment for a full breakdown of oil flow through the 2009 motor. (the two thin big squares represent the engine and oil pan, items are located in the thin squares if they are in the oil pan or in/on (not just bolted to) the motor


dannobre: see we're actually agreeing in totally different ways on the core subject. I despise the OMP because it can't tell all the conditions available to it even the basics such as oil performance in the system which is so important to it functioning properly. I fully agree the PCM isn't "sure" of the info, i'm just saying it *knows* what it should be seeing in optimal conditions, the mechanical system as you said is basic, kept basic on purpose to prevent malfunction that's why it only monitors things that would effect that mechanical object. The only direct factor is the stepper motor like you said. No need to monitor the mechanical aspect in a "set rules" environment (good running, good oil, good oil level, etc again) once something triggers it to know the needed things for the OMP to operate in the *expected* manner are out of whack the OMP reverts to the basics "oil lowest position + rpm & cutout when oil metering pressure is unattainable" limp mode. I think i'm just overexplaining to try to make it clear since some people require more info to understand the subject, my apologies. And again, so you know, i hate the OMP, i understand it's levels of suckiness, but i know how it operates which is why i hate it.

kevin.

dannobre

iTrader: (3)

We definitely agree on that

I hope they have added some pressure/flow feedback to the new electric pumps on the new engines........Shouldn't be too difficult to do

Easy_E1

iTrader: (2)

Would the OMP simply reroute the oil if one became clogged? I mean it feeds all the lines with the same source. Not through individual pumps. So if one clogged I'm thinking the OMP would not know the difference. And simply due to a restriction in flow to one of the injectors it would simply divert the oil being supplied to the remaining injectors. And one would never know. Until some one rebuilt the engine and noticed a bit more wear in the failed injector location.

dannobre

iTrader: (3)

You are right...the flow on the other lines would go up a bit, but there is no way to tell.

I pulled them when I had my UIM off and checked them...they were all OK on mine..but I seem to remember Jeff had some failed ones on one of his engines

GeorgeH

iTrader: (2)

You are welcome.


Exactly. Which is why it is relatively easy for the ECU to predict it's behavior. Which is to say, some smart guy back at Mazda figured out how much oil is needed to protect the motor (it's already been argued whether or not he got that part right LOL) and designed a simple delivery system who's behavior could be determined by some basic flow equations and then controlled by the stepper motor. Of course it's all approximate, and with the variations in oil viscosity & conditions, it can only be "so" smart in the absence of sensors.

Which brings me back to my point - it seems to me the further you get from the Mazda reccomended oil weight (and I consider 5-30 to be the "real" reccomended weight) the further you take the OMP system out of it's normal operating zone.

Can't say by how far, and how significant it is, but the conclusion does seem to be logical, at least in principal.

But that's why folks pre-mix, I suppose. Use the heavier weight to protect the bearings and premix to protect the seals.

RotaryResurrection

iTrader: (3)

Dannobre is correct...the PCM has no idea if the OMP is actually flowing ANY oil. It merely opens the floodgates a crack and expects that the predetermined acceptable amount of oil will flow through.

I know this because, I blocked off all 4 OMP ports on my rx8 as an experiment, using short solid (non-banjo) bolts. I then ran straight premix for one oil change to see if the oil level dropped or rose...it did not.

During this time, there was never a code for an OMP issue. The OMP had no idea that zero oil was flowing through it...it was still opening and closing as normal, but obviously no oil could flow through. Think of it as a waterhose with a sprayer on the end, and a spigot. Even if you open the spigot wide open (OMP) if the sprayer is closed (blocked injector, line, or blocked off OMP ports like mine) nothing will flow past the spigot.

IN this case the spigot is to dumb to know that, it only knows whether or not it is open.

For the rest of my experiment, I put the bolts back in and am monitoring further oil changes to see if the oil level drops...thus far it has not. This tells me that my OMP is not injecting any significant amount of oil.

The dumb OMP has been the same ever since the first e-omp in 1989. On those cars we actually sometimes remove the OMP from the engine altogether, so that it is neither delivering oil or being driven by the engine drive system, in order to run premix but still retain a stock computer. As long as the stepper motor and position sensor are plugged into the harness, the ecu/pcm is kept happy...it simply wants to trigger the stepper motor and see an expected change in position, it doesnt know or care whether anything is flowing internally or externally through those passages.

dannobre

iTrader: (3)

I know mine works..I cranked it up to step 60 on a flash...and it dumped oil in like crazy.

It also uses about 1/2 l / hr on the track......

The nozzles would be worth checking if you have your UIM off

Easy_E1

iTrader: (2)

Mine is working also. I know from the last HPDE session. It used about 1/2 qt. in the first two 20 minute sessions. But it is cranked way up with the Accessport. And I premix. So I had plenty of lubrication.

That's what she said!

teknics

I had both of the injectors on my fd 13brew fail (check valve failed) in the injector allowing OMP oil up out of the injector.... but onto these new injectors as you point out......

That check valve you're referring to is still there, it's just been moved and is supported by a spring which must be rated to the specific pressure of the oil in the OMP line at the time of "Oil injector on" command. This provides both things the old oil injector did, it prevents the pressure effects on the motor side of things from interfering with the pressure in the line. By taking out the air sucking part you prevent putting oil back into the intake system which probably improves emissions or something. However the downside is knowing if the check valve fails seems impossible. Overall inspection of the injector seems like it would require removal for testing...which is stupid.

yea exactly what we both realized we were agreeing on. The OMP mechanically is never assumed to fail because it is a super basic system therefore it is not checked nor are the other conditions of a motor that are "assumed" during design. We were just showing the same picture from different minds, mainly due to a typo because of laziness to fully explain and amazingly from like the last sentence of the whole post. I personally thought id **** that post up somewhere in the beginning, not the perfect state of mind .

That will continue to realistically be unproven, as it's hard to get someone with the right equipment to do real R&D style tests.

Considering that viscosity slows flow yet increases pressures the differences caused by the two may completely balance themselves out. One of the reasons it is so important to not miss oil change intervals.

As of right now I'm thinking it has a chance of balancing out but only with some actual testing will anyone find out. I don't have the time nor the real scientific measuring systems to carry out the tests to any degree of "conclusive", and thats why motor oil "preferences" and "myths" will always exist especially with rotaries.

kevin.

secret8gent

dang IB 'maintenance' last night blew away my post, it went something like this:

series II omp system has a [real] pressure sensor?

since series II is electrically driven it could fail with zero output, compared to series I which during stepping failure would be assumed to be a 'minimum' output for limp mode.

edit: one more thing...

the series one omp is a positive displacement pump, and so should be minimally affected by pressure (assuming no air gets in there?)..

series two is what kind?

i would think that in the event of some blockage, the mechanically driven pdp would be more likely to overcome than the electrical one (but i've got no specs on the driver motor).

~

also I 'approve' if they really did remove the air system to the nozzles.... (has this truly been confirmed?)

i wonder if the new nozzle check valve spring is strong enough to prevent engine vacuum draining a bit from the lines.... I suppose it must be, and I like that solution better, than the old one which would just feed in air if the nozzles saw vac.

teknics

that is a pic out of a mazda '09 rx8 manual.

kevin.

GeorgeH

iTrader: (2)

Interesting! In that case I take back all my comments about the viscosity affecting the flow rate. For that matter, the condition of the oil shouldn't matter terribly either, although of course these factors matter in terms of how well the oil lubricates the seals.