I have examined an injector in the past when there was a post on this subject. The vaccum port does not affect the flow of oil into the injector, nor is it possible for it to prevent the "draining" of the oil down the injector lines when the engine is not running.

If you examine an injector closely you will see there is a direct and unobstructed passage between the point where oil enters the injector and the orfice where it is discharged into the intake manifold. The check valve built into the injector does not enter into this. The Mazda factory manual advises as a test to blow into the vaccum fitting on the injector. Air should pass this direction. Air should not pass in the reverse direction, or in other words if you suck on the vaccum fitting you should have no air flow. This is all the manual advises on injectors. I agree with the earlier post on the vaccum being used to equalize the pressure on both sides of the injector. This is all I can see it could possibly be used for.

Speaking at least for the mechanical OMP, there is no check valve in it at all. Therefore there is nothing to prevent the draining of the oil in the lines back into the engine when the car sits for a period of time. If you look at the way the system is laid out, you will observe the oil pan is obviously lower than the OMP. Oil remaining in the galleries will drain by gravity in the reverse direction from which it normally flows when the system is pressurized. This will include the oil in the OMP and its supply gallery.

When I rebuilt my NA, I installed an adapter that allows two stroke oil to be fed to the OMP. It is a simple device, and it works by blocking the oil gallery that feeds the OMP and instead allowing the two stroke oil to be used. The adapter is essentially a block of aluminum with a short "driveshaft" and seal and a hose fitting. The seal prevents the pressurized engine lube oil from getting to the OMP. The instructions furnished with this adapter state the reservoir needs to be at least six inches higher than the pump for the device to work. When I used the sub-zero reservoir to hold the two stroke oil, the oil drained out of it by gravity/siphon when the engine was not running. This oil flow was through the internal clearances of the OMP, and would amount to a couple of ounces overnight. The flow of oil here was through the hose supplying the OMP, then into the injector lines and finally into the intake manifold through the injectors themselves. I had to install a vaccum operated check valve to stop this draining of the two stroke oil. This valve is a purge valve intended for a Chevy emission control system. When vaccum is applied to it the valve opens and permits the two stroke oil to flow to the OMP adapter.

I do not pretend to know all the intricacies of the OMP system, but I for one will not panic if air is in the injector lines when the engine if off. I do not see how it can do otherwise, given the mechanical nature of the injectors. Remember, the normal operation of the OMP allows for virtually no oil at all when the throttle is at idle. It would stand to reason that the need for oil at low power is minimal. If you observe the "air filled" injector lines, you will note they fill up rapidly when the engine is started. It would therefore make sense to treat your rotary like any other engine and not demand high power output or subject it to high RPM operation before the engine warms up.

 

Well it would appear that SixRotors has filled in a piece of a mechanical puzzle.

Yes, apparently those ARE vaccum lines.

However, I dont have smoke in my exhaust, but that WOULD explain that problem.

Now, I verified with a Mazda service center that oil lines that reverse flow, will lead to air in the lines and that this is bad.

More to come as I install them.

 

I think it's time you looked closer at what you are doing and where the hoses are going to... The vac lines on top of the injectors go to a 4 way tee.. this then leads to a nipple at the back of the throttle body... The hoses are under vacume almost 90% of the time...

You seem to be convinced that the checkvalves are the source of the air in your lines.. yet, everyone has explained to you how the checkvalves would be the cause of the air getting in your lines.. but you want to investigate this further...

#1 - you state that mazda told you oil lines that reverse flow is bad... well of course this is bad.. if your oil lines reversed flow you wouldn't be getting any oil into the motor would you?? However there is no possible way for oil to flow in the reverse direction when the car is running unless you decide to pull the line off the injector side and blow through it!

#2 - copandengr explained it quite well.. oil WILL drain back down through the lines when the car is turned off ..it's called gravity.. where else will it go?

 

I agree i made a mistake about the vaccum going to the top of the injector...

However, the fact that the new oil injectors, now that they are installed, DO NOT allow air back into the lines is proof enough.

I mentioned earlier that only the bad (leaky) injectors had this problem and that they were slow in pressurizing.

Now they are all black, all the time.

Before, they would bleed air in about 2 hours.

Now they are all full of oil all the time.

I also think its noteworthy that the other "good" injectors, never leaked air, even after a week if disuse.

None of these cars are brand new anymore and therefore most of us are going on what the "new norm" is here by comparing the median operation of these cars today.

This seems to happen in every group diagnosis of a problem these days, and is understandable, but I am spending my time "base-lining" these cars normal operation, and this is the behavior i see from the oil injectors:

Leaky injector = air in the lines = the need to replace the injector soon.

this is not to say that they wont work, but the ARE in a degraded condition.

This is what I asked the Mazda mechanic, a person that is the leading rotary mechanic in the southeast, (according to the wall of certifications he has.) - more that anyone else i have ever see on any car.-

I agree that there is some abiguity as to the actual pathology of a failed injector still, but i feel conident that I have discovered that air in the lines should not be possible if the injector is not leaky.

I had to use a vaccum pump to show the leak, but it was there. the others that were not leaky held thier vavles closed beyond 20hg!!! i didnt dare go further than that, but thats MUCh more backpressur than i think they would ever see except in a backfire-through-the-intake situation.
(which is impossible on rotarys.)

 

NO, NO NO NO NO. There is no vacuum at the nipple on the throttle body that the spider goes to. That nipple goes to a path thru the black phenolic block on the tb and then directly to a passage that leads to a quarter inch hole at the front of the throttle body. In front of all the throttle plates. NO VACUUM AT THE NIPPLE. I took a turbo and a N/A throttle body apart to find out why there is no vacuum and its because the nipple leads to a quarter inch hole in front of all throttle plates. If you have a n/a start your car and pull the hose from the spider off. There is a vacuum FROM the spider but NO vacuum from the nipple. I drove around with a six foot long piece of vac hose from that nipple to the drivers seat and drove at all speeds with no vac. Then I tore the throttle bodies apart and found out there is not supposed to be a vacuum FROM the nipple. Just because there is a nipple on the throttle body does not mean that a vacuum exists there. All nipples are not equal, as you may have observed in life. Don't ask me how the darn oil injector system works. I just know how it does not work. Carry an extra quart around with you. Oh yes. The vacuum on the lines that go to the spider comes of course from the oil injectors. Go figure.

 

butweeeen hailers und th brke pahrts kleenur.

i m compwetewee confruzed.

i think i will go sit back down n th cornur.

Slappy_necks
MallPhrase Winkerling

 

Hailers: There is vac at the nipples... please make sure that the black plastic spacer is installed the right way.. the holes are offset.. if you install the spacer on backwards then it blocks the passage and it will not draw any air through the nipple as you describe.. Thre are normally 3 lines that go to the back of the TB nipples.. the larger of the nipples goes to the oil injectors.. the 2 others normally go to the secondary plate checkvalve and and to the subzero valve under the manifold...
Trust me.. it's very easy to take apart the TB, accidently put the black spacer back in backwards and end up blocking the passage holes which results in no vacume coming from the nipples..

 

hey !

you made that up !

but it is true.

 

OK people. I checked my TII, and what HAILERS says is absolutely correct. There is NO VACUUM on the top 3 nipples (including the larger oil injector nipple). Yet all my other ports have vacuum correctly, including the port feeding the purge valve, but only after opening the throttle a little bit. Hence, the plastic block IS CORRECTLY INSTALLED! So the vacuum equalization theory is just plain wrong. If you read Six Rotors post, you will note it says "Air is led from the throttle chamber". Everyone seems intent on translating the word "Air" to "Vacuum". Keep an open mind, here. What if "Air" meant, like, AIR???? Seems like what Mazda is doing here is providing "Air" from a clean source (the throttle chamber) to get sucked into the injector instead of the oil! Yeah, I think they should have used the vacuum equalization method, but they did not. Instead, they chose air to substitute for the oil. (There it is again, "AIR"). HAILERS traced it out, and he knows what he is doing, so accept it, it is so.

And while were on the subject, Sniper_X is correct also, imho. Yes, there is no check valve in the OMP, but the check valve in the injector would not allow air to flow back into the oil lines. So if the oil starts to flow out of the lines, it will create a vacuum, which in turn would stop any further oil flow. I looked at my oil injector lines after replacing a leaking injector, and guess what? There are no air bubbles in them, even after sitting an entire weekend! Keep an open mind, here, folks, you might learn something! I know I sure am, and have learned tremendous amounts from this forum.

Enough of this Tirade. Just my 2 cents worth (probably not even worth that!)

Irv, Keith's dad

 

Yo, Six Rotors. I meant to say I read your post and, yes Irv, I did see and catch on to the reference to air from the throttle body(not vacuum). And Ng, nope, I installed the black phenolic block correctly. By the way this is a 87 turbo model and it has four nipples. Other models may vary. I also did the 87 N/A. Same results. When I found no vac,I took both throttle bodies apart and found out why. Why? Because the nipple for the spider leads to an opening approx 1/4 inch in size, in front of all the throttle plates, hence ain't gonna have a vacuum. Throttle body is'nt that easy to remove on a 87 turbo. Goes to the throttle body for only one good reason I can think of...clean filtered air. Thank you Irv for double checking me. Hmmmmm. Lack of trust there? (humor)

 

I'm going to stop argueing with the 2 of you.. you guys seem intent on your own findings and that is fine...
These are my observations on my 88 10 AE, my old 87 T2 and another 87 T2 .. the nipples at the back of the TB DO have vacume.. Here's a question you can try and answer.. one of the nipples in the back goes to a one way checkvalve which goes to the double throttle plate diaphram (You can open up your FSM and look at the vac diagram).. If all these nipples were doing was supplying clean air, no vacume, how does the diaphram operate to open the secondary plates?? by magic??

I have seen boost guages hooked up to the nipples at the back of the TB.. and guess what.. they show a draw of vacume... I have pulled off lines from those nipples.. guess what.. there is a vacume leak when they are pulled out..

You guys seem to want to be the authority in all matters rotary...but it also seems like there is alot of wild guessing here and there.. Just because it's one way on your cars, it must mean it's the right way... that's plain wrong..
Ahh well.. whatever.. You work on your own cars, and I'll work on mine.. we'll keep thing civil that way

 

Keep in mind that the injectors are different for 89-91 than they are for the years that your car comes from...


However, we could easilly reverse the roles and point out that you are the only one with vaccum at these oil injectors.

Whats wrong with your car?

 

Thanks for pointing that out Sniper, after re-reading my message I realized that I was being pretty hypocritical about the whole thing and so I appologize..

I will also appologize for my sweeping statements about vacume being present at the nipples behind the throttle body.. Although I can confirm that there is in fact vacume on the smaller nipples, they were correct about there being no vacume present at the larger nipple that connected to the oil injector lines..

Sixport was correct in the way the system functions.. the vacume from the motor is drawn through the injectors, passes through the checkvalve and allows fresh filtered air from the nipple in the TB to be drawn into the motor along with the metered oil.. the check valve is in place to keep oil from being drawn back up through the vac lines and into the TB.. I've priced out the injectors from the dealership before and they are quite pricey.. the primary injectors being $45 each (canadian) and the 2 peice secondary injectors being $45 for the injector and $45 for the checkvalve each... I don't understand why mazda didn't just use a single checkvalve installed into the vac line that goes to the nipple and simplify matters.. but perhaps those of you with injectors with bad checkvalves might want to go that route (checkvalve is only a couple bucks from an autoparts store...

However I still stand my my comments that there is vacume present at the other smaller nipples on the back of the TB.. and no, this wasn't jsut verified on my own vehicle, but on 2 other T2's as well...

 

I have been reading this thread with much enjoyment and also much enlightenment! I am in the process of putting back the engine after taking it down because of stuck 6-port sleeves(another story in itself) and checked out my oil injectors to see if they would pass air both ways. Well two of them did and this might have caused my engine to smoke occasionally at start up(never any other time) I then thought that maybe I could clean them and voila, I did! I took a can of carb cleaner(my "clean everything" choice of stuff) and sprayed this into each injector at the nipple end and cleaned them out real good. My theory was that gunk from the oil gets into the injector and clogs it open. Well, they now work as good as new ones!
Any comments?

 

WOW ill do that too!

Good idea.

 

Hello Zoom, Zoom, Zoom. That check valve is made out of rubber and looks like a poppet valve. The stem runs inside the nipple on top. Just FYI. The bad ones I have all came off a car that had a engine fire. Melted the plastic part the bottom of the valve sits on. I can see where they could be cleaned if there has'nt been a fire. Lucky you.

 

Thank you Chris Ng for pointing that out to me. Do I appear that way in other posts as well??? You have my sincere apology. I have a character flaw, when I think that I am right, I get all excited and jump up and down because I want the person to see what I just realized to be "true". A lot of times I am full of sh-t. In either case, this was meant as spirited discussion. I never intended anything I said to be taken as a personal attack. If I have offended others in this thread, I apologize to them also.

Expert in all things Rotary??? Oh yeah, lemme tell you about that. Yesterday, I took our TII out for a spin. I got caught in some traffic, and after about 15 minutes, the temp guage was 2/3 up towards HOT. I immediately pulled into a paint store driveway, popped the hood, low and behold the electric fan wasn't working. I cut the engine immediately, investigated, found a blown fuse for the fan. Further investigation revealed a pinched wire between the battery and the fan shroud mount on the radiator. Fixed it, got a new fuse, let everything cool down and went to start her up and drive on.
Then the fun started. The car would start and then stall immediately. The more I cranked it, the harder and harder it became to even start. "Darn, I must have blown the engine!" I thought. Well, it ran smoothly when it did start for a little bit. Whew! OK, must be the fuel pump switch in the AFM. Pulled off the connector, checked all the contacts. OK. Pulled off the rubber cap from the plug, checked all wires. OK. Reseated the connector and tried to get her running 3 times at least. No go. Scratched my head, thinking "How am I gonna get her home?". Got it! Called the wife, had her bring me my initial set connector for the fuel pump test plug, along with my meter. Plugged it in, confidently started the car. Ran for 1 second and stalled, just like before. Shoot, must be I have a massive intake leak somewhere. Since I had pulled off the IC to check vacuum lines for our thread, I figured I must have forgot to tighten something, and the heat had made it let go. So I started pulling on every hose I could get my hands on. Got all greasy, found no hose even the least bit loose! Heck, Now it looked like I would have to have it towed! I sat on the grass for a long time, looking at the car, trying to think what I had missed. Oh, I noticed the car was on an incline... I was running on fumes when I pulled in....

Long story short, 1 new gas can and 2 gallons of gas later, she was running. Mr. Rotary God had just spent 4 1/2 hours troubleshooting running out of gas!

Irv, Keith's dad

 

I've been asked..

"Why do I spend so much time cleaning the engine bay?"

Because I get myself into situations like Irv, Kieths dad.

So if im gonna have to start pulling on stuff, at least i'm not compounding it by getting greasy in the process too.

That would only make me more angry.

And the running out of gas thing?

Priceless.

And you even called the wife.

Theres just no hiding that one!

 

Gee wilikers. Its like this. On a 87turbo there are four (4) nipples on the back of the throttle body. Only the bottom one emits a vacuum(can you EMIT a vacuum?). The top three are nothing but a path for ambient air from a hole located in front of all the throttle plates. The nipple for the spider for the oil injectors shares a common path with the other two nipples, and it goes straight to the front of the throttle plates. Take one apart and look sometime. Its a lot like the fuel pressure regulator that has a vacuum on it all the time except during the 50 or so seconds during hot start, or when you step on the gas, except in this case neither of the top three have a vacuum coming from them. The above you might note is clarified as a 87turbo. What some one did with another turbo model is not for me to say. I'm tempted to go out and buy another model to find out. Lighter rotors might be worth it.

 

At least you figured out your problem in the same day. I left mine(85 GSL) at work for two days while I stressed as to why my car would not start. I took a lot of **** from my co-workers when I put a gallon of gas in it and it started after a few cranks. Sometimes I wonder about my abilities......

 

dude this thread is like 6 month old

 

Just to let you know.
I have had the same air bubbles in all of my rotarys. And I have owned multiple rotarys.
I've hit 170k+ on ALL of them. I had a 12a that still ran fine at 285k. And all had this "problem".
I believe that it might not be the preferred way that we would wish it to work, but it has not caused a problem on any rotaries that I know of. Can anyone proved that it was the source of a rotarys untimely death? The only time I've heard of anything close to it is when a 89-91 OMP goes down.
Why argue about it? We all know that it doesn't hurt to put new oil injectors in and new lines are good, so if someone wants to do it, don't discourage them. I, however, am happy with mine working the way they are with their air bubbles ...
Another thing - do you think that the air hurts the engine? Of course it doesn't. Is the oil not getting to the engine? Crank it up and look at the lines with it running at 4k rpm......

 

I was just happy to see that someone else had a hard time trying to start their car when it was in fact out of gas.

Is it bad to bring back old threads?