"Oil Injectors" - why do the need a pump (omp) and vacuum? And can they leak?
 

Hi there,

As per the title really. I am getting alot of oil blown out the air recirulation valve on the y-pipe back into the airbox. The turbos have been checked twice now, with brand new seals in both turbos. The turbo people keep saying they are working correctly, so there must be a problem elsewhere. So where is the oil coming from?

I can only see 3 possibilites of introducing oil into the y-pipe area. 1) turbos 2) breather pipe 3) oil injector vacuum line.

Assuming the turbos are fine, it leaves 2 and 3. The breather pipe is actually dry - no oil in it at all. I also fitted a catch tank to the line just to double check, no oil caught at all, but the problem still persisted. So that leaves 3.

QUESTION: the oil injectors seem to have oil pumped to them from the omp, so why do they also have a vacuum line?

QUESTION: can something fail at the oil injector end, and so allowing oil to be drawn down the vac line to the turbos - and therefore giving me the symptoms I am seeing?

QUESTION: if it is the vacuum line allowing oil to the turbos, does this mean the oil injector is NOT working??


Any information would be hugely appreciated!! :icon_tup:

Thanks!!:icon_tup:

Yes, the oil injectors need vacuum to work properly. However, there is a check valve in each injector to prevent the oil from running down the vacuum line. These can and do go bad. You will need to replace the oil injectors if this is the case.

Thanks for the reply! :icon_tup:

The oil injectors have a hose that runs to the primary air intake to the front turbo. This is for filtered air to be sicked into the engine thru the oil injectors when it opens.

oh wow, i was about to ask the same question, time to replace my #1 rotor oil injector.

kevin.

So you reckon this line pulls air against the vacuum that the primary turbo is pulling, even under acceleration? Is this correct?? I have read elsewhere that the oil injectors take boost from the manifold, to help disperse the oil into the chambers.

No, follow the vacuum line routing diagram. The lines from the oil injectors are routed to the intake elblow of the primary turbo. This is to supply filter air, there is no boost applied to the vacuum lines on the oil injectors and they are not under vacuum, if any it is very slight. You would have to have a very clogged intake filter for the oil injector hoses to see any vacuum. The oil injectors only work one way that is into the block, the test for them is to verify that they do not flow out towards the rubber hose.

Maybe it is inexperience, but I don't quite understand this. Maybe vacuum is the wrong term, but the volume of air the primary turbo is sucking must surely cause negative pressure (when viewed against atmoshperic). You've only got to put your hand over an air intake to feel the suction. Surely therefore, the line from the oil injector to the intake elbow on the primary turbo is used to apply a vacuum (or negative pressure) to the injector, and not used for filtered air?

To check this, I placed some clear tubing in the line anyway - and I can see oil in this line, and it is moving from the injector towards to intake elbow, not the other way round.

Having oil in this line - does this mean that the check valve is failing? Or would you expect to have "some" anyway? It is difficult to specify how much oil is there, though, 'cos I can't see whats happenign when I am driving, only when I have stopped!

Since you have located the line that supplies clean air to the injectors, you can test the check valve. You should only be able to blow into the line and you should not be able to suck air from it. Although it tastes good, try not to eat too much oil doing this test.

but not when compared to the vacuum created by the rotor in that section of the housing

I am pretty sure that the intake charge is already entering the chamber once the oil is being injected. I could be wrong though. I would need to see a cutaway to compare apex seal placement to intake port "opening" to oil injector location.

The air inlet line isn't really a vacuum line as has been pointed out; however, if the check valve goes bad, BOOST can blow oil back down the line into the turbo inlet.

Again....the line supplys filtered air only. The gentleman above explains it again very well. some folks just leave the vacuum lines off the oil injectors. Unless the oil injector check valve is comprimised, then oil/boost will NOT flow backwards. Look at my picture of setup. I have a small filter on the PCV hose AND oil injectors hose together. All THREE of my cars have the same setup.



Later

Here is a pic of the filter.

Thank you to all who have answered, your insight is appreciated.:icon_tup:


So basically, the line from the oil injector to the primary turbo elbow allows filtered air to go TO the oil injector, which is under vacuum due to the rotor chamber expanding at this moment in time after passing the inlet port. A check value is present to prevent any oil running down the tube when the oil injector is not under vacuum conditions. Therefore, if there is oil in this filtered air line, it is possible that the check valve is compromised.

How efficient is the check valve - i.e. does it prevent ANY oil leakage?

Correct. I have not heard of a bad check valve in one as of 10 years here. But there could of been.

Hi there, me again!

I took the line off the primary turbo intake elbow - I can easily SUCK air (i.e. FROM the oil injector TOWARDS the primary turbo inlet), but it is difficult to BLOW air (i.e TOWARDS the oil injector). While it is difficult to blow down the tube, it doesn't take much effort to get air moving and you can hear a "bubbling" sound from the top of the engine area (although difficult to identify where exactly).

Obviously the opposite to "aleximen" suggestion.

Is this correct?

I also plumbed in 2 small tanks into the line so I could see and collect any oil in the line. In about 100miles of driving, with a fair few WOT runs, I collected around 8ml of oil travelling from the oil injector towards the turbo inlet elbow.

Is this amount of oil normal?


A bit of a puzzle, but any thoughts are welcome!!

Cheers!

My #1 rotor's oil injector has a bad check valve, oil comes right out of the hose, could figure out what was leaking until I saw a little drip come out of the hose.

just so you can now say you know its happened.

Luckily I always run premix as a safety margin so I'll replace it as soon as I can.

kevin.

That's about 8ml (of oil) too much. There should be none--it should be dry.

if I blow through the valve when I take it out towards the vacuum line side I shouldnt be able to feel air on the other side right gentleman?

Bringing this one back from the dead...

my question is since im doing non-sequential (and this may not matter if its NS vs. S) is it ok to leave these vacuum lines off and let them suck in unfiltered air?

The question is why? If it works as is and the lines are not causing a problem with fitment... why change what you know works?

I appreciate your opinion thanks, however still didn't answer my question. If you must know I want less vacuum lines.

I do not have vacuum lines on my injectors, not for several years ,no problems .Before I removed them I checked with three of the well known rotary shops and they all said the same thing ,they are not needed .

The oil injectors only need a source of filtered air. No vacuum is needed to work properly.

If you cut open an oil injector you will see that it is just a simple check valve inside.