Picked up an 04 RX8 with 72K miles and 3k miles on a reman Mazda engine. The service history does not indicate the reason for engine replacement other than low compression. To mitigate excess wear on the new engine, I am inspecting the common peripheral issues including clogged cats and bad coils. I am now focusing on the oil injection system. After researching information on the OMP, lines and injector nozzles, it is not completely clear what is the most effective process for confirming the system is in good working order. I am hoping those with far more experience can lend their insight. Here is what I have so far....

First, I started premixing with a JASO FD rated oil. Second is I have confirmed the engine uses oil, but have not driven enough to determine the exact consumption. The oil was topped off when I first inspected the car and after about 50 miles total including a pretty hard test drive it is down maybe 5mm from the top line. I just did a fresh oil change and will measure from there.

The three components of interest are:

OMP: From what I can tell these fail rarely and functioning other than expected will throw a code. Once it is confirmed oil is being pumped, there is no other practical inspection or preventative replacement.

Oil Lines: These seem to be pretty suspect, either by cracking or clogging. It seems they should be cleaned or replaced. Either way they need to be accessed at both ends to confirm which seems like a bit of a project.

Oil Injectors: The factory manual has a process for ensuring the injectors hold vacuum. Assuming they do, does that mean they are 100% good? Should they be removed, inspected and cleaned? Or just replaced?


Obviously if regular oil consumption occurs it is likely the oil system is functioning, but it doesn't indicate each oil injector is functioning 100%. How far should I go to confirm this? Should all the injectors and lines just be replaced? I assume that is a project involving at least an upper intake removal. Also parts cost would be about $800, correct?

I know there are many previous threads that cover some of this, so I do appreciate insight from the more initiated.

Thank you,

 

Search is your best friend.

https://www.rx8club.com/series-i-tec...-macro-271354/

https://www.rx8club.com/series-i-tec...cation-268559/

 

Thanks, I read both those, I especially liked the "mad scientist 101" comment. Interestingly those threads helped inform my decision to NOT run a SOHN adapter and go with the dirty oil injection. However that is another topic for another time (past or future).

You have been down the road I am about to travel. If you were in my situation, what would you do? Try cleaning the lines an nozzles? Replace them? Leave it all alone and hope for the best?

Thanks,

 

I would vacuum test the nozzles. It's very likely that at least some no longer hold vacuum. Whether you choose the replace them is up to you. The vacuum function doesn't prevent oil from flowing, but it does mess with the quality of the oil delivery. You could choose to premix anyway (regardless of the injection system condition).
I don't know how you would clean the lines and manipulating them risks breaking them more than anything, so I'd either leave them alone or replace them entirely if you're concerned.

 

I have my own technique for cleaning the lines and the oil injectors without even removing them from the car. The problem with the technique, or rather the issue it doesnt address, is that it is so passive (no major disassembly required) that theres no way to know if the check valves in them are still functional. So removal of the UIM and other components to get access to the oil injectors to manually test them for vacuum. That said, lets check out what I personally do (not fool proof mind you, but its better than nothing)

Whats required?
-Chevron Techron Injector Cleaner/Fuel system treatment
-Few ounces of 2-stroke oil or premix
-MAF cleaner
-A 5/16 or 3/8 vacuum cap
-Help from a friend to make it faster and easier

Make sure during this process that you have premixed your engine oil in your tank at a ounce per gallon ratio to provide additional lubrication to your engine/seals during this cleaning process.

How to:
1) Open the hood and make sure the engine has made it up to operating temp. You can just let the engine idle until the temp gauge on the dash reaches the middle for at least 5 minutes. This will help a little with helping the cleaners thin and creep their way into everything rather than run straight through.
2) With the engine running, remove the vacuum breather/hose from the intake that leads to the OMP vacuum distribution block. Use your vacuum cap on the intake nipple so you dont need to keep it plugged with your finger. At this point your engine will probably want to idle funny.
3) spray a bit of MAF cleaner down the hose 2 or 3 times in a few second long bursts. your friend will need to sit in the car at this point and hold the throttle to maintain around 1,000 rpm. You want to keep light throttle so that the engine stays idling low and as far into a vacuum as possible but not allowing it to stall.
4) next, slowly feed about 1/3 the bottle of techron into the oil line with the engine still running. After that go ahead and shut the engine off, and when the engine is off go ahead and pour a few ounces of techron into the oil line, the remaining techron you can pour into your tank.
5) while you wait, now would be a good time to go ahead and knock out cleaning your MAF with the same MAF cleaner.
6) after about 15 minutes of letting the techron do its thing, go ahead and start the engine once again while using your thumb or something to plug the line. this will help the cleaner be pulled through the injector easier upon startup.
7) Once the engine is back running, pour a couple of ounces of 2-stroke oil or premix into that oil line. this will help a bit with any harsh chemical residue left lining the inside of the hose or vacuum distribution block for the oil metering injectors.
8) Keep your thumb/finger on the oil line blocking airflow for about 5 minutes while the engine is idling. This eliminates the siphon break that the vacuum line functions as, and as the engine idles it will with the aid of the engine vacuum pull oil through the metering lines at a accelerated rate. You can use this technique after completing an oil change to get fresher oil into the lines more quickly. You can also use this technique to prime/fill a new oil line quickly following replacement/installation.

And youre done. Reconfigure everything back to how it was prior to the cleaning service.



Again, to make sure your injectors are good you need to check/test the vacuum on each oil injector individually to ensure they hold vacuum.

 

Thank you for sharing your procedure. You lost me a little on step 4, what “oil line” are you referring to?

 

Got me too, but concluded he left off telling you to take off the oil supply lines at the OMP.

kudos for not falling for the mad scientist 101 routine. Though this is a little better, imo you’re better off just pulling the UIM; which is not really all that difficult but assumes none of the bolts are seized and snap off, and just do it properly by taking the oil injectors out and use a mityvac or similar devise and a separator catch container to do that routine on the bench instead rather than with the engine running.

My reasoning for that is I wouldn’t want MAF or fuel system cleaner on the internal rubber seal and plastic support piece for very long as it might swell, become affected like become brittle, soften, or have some other issue. It’s not so difficult to visualize that Mazda never intended for anyone to run solvents or other chemicals through there since their only factory procedure is to vacuum test the oil injector and replace if necessary. Doing them one at a time, and quickly going from the solvents to the oil, will help minimize that possibility. It doesn’t clean the oil lines out, but I’m not sure that’s necessary and am hesitant to recommend putting anything except oil through them.

The other issue I have with doing it like that is it assumes that everything put through there distributed evenly through all of the oil injectors, which there’s not really any guarantee that actually occurred except to do them individually where you can really see what’s going through. If you’re serious, then be serious about how you go about doing it.
.

 

Before Sohn installation, OMP lines look dark, few 1000 miles later they look clean.
At moment, few liters of premix oil later, they look pink.
I did a comprehensive study on the oil injectors and dig as deep as no one ever did before, the design is based on mechanic fluid like air stop carburetor power system to be more specific.
You can not clean( cure leaking injector) as the failer is not due to dirt, it's caused by diaphragms losing their elasticity.
If harsh chemicals used it will make them leak more, irony.
Oil makes them sticky and seal. The best is to replace them with later revisions, those the have groove on hex part. elongate air feeds (vacuum line) use clean oil.
IMO.

 

I certainly don't mind investing in some time to ensure the system is working to it fullest. From what it sounds like, there is no way to avoid a bit of disassembly to access the injectors and the lines. I also have concerns using harsh chemicals inside the injectors. Clean does not necessarily mean functional. I am leaning to just replacing the injectors as a matter of preventative maintenance. The lines on the other hand seem like they can just be inspected and if they flow oil and don't leak they are good. But then again a set of lines is $200, so we will see.

Either way, I will plan to remove the UIM and access the injectors. My plan is to drive the car for a couple of tanks using a heavy premix. That way I can confirm the oil usage before I disassemble anything.

 

Why not just replace the lines? I mean they are now decades old....

 

You may find that it doesnt consume oil, as in - the level doesnt go down. Some have found that when premixing on a street car, enough two stroke is bypassed down to the sump to compensate for anything burnt. My series 1 is one of them. I have determined my OMP system to be functioniong correctly, and premix 8oz to every tankful, which is around 200:1 i think. Oil level has never gone down. I subscribe to the redline once a day theory, but drive sanely most of the time.

 

So the theory is that the premix oil is separated from the fuel during the injection and combustion process and ends up back in the oil sump?

I think I would need to see some supporting evidence before more consideration. Maybe a uoa would show 2t oil additives?

 

I would be more willing to bet the sump is receiving fuel than 2 stroke and the engine is on its way out. Either way, I wouldn't make your decisions around the off chance you have this problem.

 

So long as you are doing regular oil changes and using good oil, your lines should never get clogged or dirty, Also as long as they are not broken or cracked they should be completely fine to keep and continue using. Its the oil injectors themselves that need inspecting and replacing as needed.

 

more sensible!

 

Yeah, once you confirm the oil injection is working and the oil level does not drop, fuel must be blowing past the seals. I am not sure what level of this is acceptable but I would think a uoa can confirm if it’s within range.

 

Just heavy Pre-Mix in fuel and save all this BS, the MOP's on S1 are rubbish after about 100K, also the lines becoming fragile is nothing new all Rotaries have this issue, even S2s use a smaller or shorter line (6 x 4 inch) made of same clear plastic crap. But the EMOP system is the best yet.

Winter where I am and I have my S2 on the road after driving NC2 all summer, I know I keep saying this but MAZDA really fucked up by never offering a RENESIS in an NC, what a combination that would have been with little extra tooling cost as all the critical dimensions are the same all would need would be a shorter PPF and prop-shaft, Diff and beefing up of brakes and suspension to RX-8 level.
Sadly the rotary will never be new again...as a main power driving engine.

BTW, in case you guys do not know the UK has joined all of EU (Europe) where all gasoline and diesels engine cars will not longer be sold new after 2030, less that 9 years time...
Only US will be selling them new, don't know what Japan, Canada is doing...or AU or NZ, but we will follow EU.

 

 

If you premix heavily, and/or use the factory system with a Sohn, you will get 2 stroke oil in the sump even on a new properly built engine. Especially in normal street driving, where the amount of unburnt oil will be greater than under high load racing conditions. I have seen people question this repeatedly, I don't understand why it is difficult to believe. Fuel will also end up in the sump, but fuel evaporates at normal oil temps, 2 stroke oil does not. This happens in piston engines also, even ones with excellent ring seal. I've said before, premix in your Honda or Toyota, and watch the oil level rise. Why do you think motor oil turns color in any engine with use? Anything in the combustion chamber that does not burn or gets blown out the exhaust will get blown by the seals (piston or rotary) into the sump. Maybe this will help:


Piston aero engine running leaded fuel. Oil has Low fuel dilution, high flashpoint, tons of lead. Fresh oil added during interval. The fuel has evaporated, and the lead compounds from the fuel remain, because they do not evaporate at the oil temps this engine sees. The average stated here is almost .5% lead content, for an oil fill that has none when formulated. So, its more than certainly possible and actually probable that if you premix heavily, your premix will end up in the sump in certain concentrations. It does not indicate an engine problem if this occurs. It is normal. It happens in piston engines with much better leakdown numbers than any Wankel will achieve. Think through this on your own and you will no longer question this effect.

 

That's a fair point.

 

Thanks.
And I will put this in here also. Almost every time there is a new owner asking questions on the forum, Loki is trying to help. I would like to acknowledge how much time you spend helping out new owners and answering a lot of noob questions without snark or aloofness. I think you have probably helped hundreds by now. I know we have differed on a few things, but I want recognize your good heartedness, and commend you publicly for it. Good job, Loki.

 

with all due respect Kevin, you present many things as fact that are at best guesses and conjecture

as you’ve pointed out recently, I’m not always right myself, but I see a lot of bad advice and information given out on here. I’m not hesitant to say so when seeing it that way, neither do I expect anything less from anyone else. Judging someone based on being snarky and aloof is just as misleading as patting someone on the back just because they agree with you. Things aren’t always as simple or as obvious as they may seem, but people who can’t get past their sensitivities and emotions are never going to reach that realization.

Christ referring to the Syrophoenician woman as a dog to her face and her reaction is a pretty good example of it imo. I recognize that those who view him as the surfer hippy dude that’s all about happy happy love, peace, and puppy dog tails and other cultural deceptions are going to have a hard time with me putting it this way. No, he’s the one that said, “bring those who would not have me rule over them and slay them before me”, as well returning in righteousness to both judge and make war.

The very same who one moment praised Peter for his acceptance of him as the Son of God, and the very next moment told him, “get thee behind me Satan”. The end result of that woman’s response had it been different might be an interesting possibility to consider. And what was my response to you when being held accountable for my own past error from 10 years ago?

The truth isn’t always easy and pain free, just the opposite more often than not, and there are reasons for addressing things in a certain manner that go much deeper than, and far beyond, how it may appear on the shallow, petty surface. Therein is the deception of a man’s pride, vanity, and arrogance, as well as the wisdom of his own conceits. There’s a time for compassion and understanding, just as there’s time for piercing the heart and soul. Which is often why people reject the truth; because they would rather take the easy way out and accept a lie rather than bear the sharp, penetrating reality of the truth.

You’re my brother and I love you, would like to believe I’d even sacrifice myself for your sake, but you’re a man and I won’t treat you like a child. That’s straight from my heart with all my soul, all my mind, and all my might.
.

 

Team,

I read your post, but right now have no time to reply. I will get back to you on this, likely tomorrow.

 

You would support disregarding the oil injection system by replacing it with heavy premixing? Does mixing oil in the fuel provide the same or better function as compared to the mop?

I ask because I plan on premixing anyway. Either 1/2 oz per gallon, if the omp is confirmed. Or 1 oz per gallon as I am doing now. Because it’s obviously a lot easier to just premix more rather than access and replace the oil injectors and lines.

Is is this an issue for the oem cat?

 

Team,

It may come as a surprise to you, but I did not have your input to the forum in mind when I made my "snark and aloofness" comment. I have other descriptors for that, that I will state later.
There are many others on the forum who absolutely destroy any noob who does not use the search function, says something dumb, etc. I own (too) many vehicles that I repair myself, and I am on other forums regularly, and this one is among the worst for outright antagonism in my opinion. I find that objectionable. It may sound far-fetched,, but I find all of the BMW forums I go to much more congenial and accepting of new blood than this one. BMW with it's reputation for elitist owners. I have wanted to point out Loki's contributions before, and finally got around to it, not because he agreed with me. In fact, I think most of my responses to his on the forum have been in disagreement.

Now to the topic at hand: I actually don't state things as "fact" often, I more often like to tell people to think for themselves. This oil blow by issue is a perfect example of that. Assuming and stating to a poster that his engine is worn because it is blowing by 2 stroke oil is wrong. Like I have said, even a piston engine with single-digit leakdown will do this. Try a fun experiment on your own car with the fresh engine to satisfy yourself. Measure your oil level, and then start your car, and shut it down when it goes closed loop. Let it cool and then do it again. Do this 15-20 times. Then measure your oil level. It will smell like fuel, and it will have risen. Or, premix at 1% in your daily driver piston car and watch the oil level rise, or normal consumption stop or slow, after 1-2000 miles. Go ahead, it wont hurt it, especially if you are using a good oil. It will likely clean the chambers. If you disagree, make your reasons clear.

Next point:
Team, I think you have knowledge that would be useful to many, if you only revealed it more. Maybe your patience is exhausted, since you have been here longer than most, and you have heard the same drivel over and over again, which I agree gets old fast. I don't know why you do what you do here, and won't try to guess the reason. Maybe I will try to engage you privately. I will say you spend more time and words condemning the thinking behind the issue, instead of addressing the issue. You also tend to hit and run, saying "bah, humbug", and then jet. You fail in many cases, but not all, to get into specifics as to why something is wrong, or state your case of disagreement clearly, so all can measure the merits themselves. Your post in response to mine on this thread is a good example. You often travel very far afield in your posts as you did in this one, making assumptions about motive, morality, etc. The bottom line is that I think you are very, very, very hard on yourself. I think this spills over into the forum, and it probably does elsewhere, too. I also think you are a good man who has been there for many people you barely know, including myself. So, I didn't have you in mind when I spoke about forum civility. My feeling about what you do or don't contribute is different than anyone else whose posting history I've followed. I think most here would agree that your contributions are wonderful, and also many of us sit in wonder as to some of the things you say, and when/why you say them.