2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Why do the oil injectors need vacuum to run?

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Old Oct 6, 2004 | 01:25 AM
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Why do the oil injectors need vacuum to run?

I don't get it?

Also, it says in the haynes that you should not be able to blow into the injector from the vacuum hookup, only suck air.

I can blow a little bit of air, is this normal?

thx
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Old Oct 6, 2004 | 01:58 AM
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pulls the air out of the line so as not to inject air? Just a thought.

Sounds like a checkvalve is leaking. if you can blow through it-- or it could be designed that way, not sure.
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Old Oct 6, 2004 | 02:05 AM
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The oil injectors are supposed to only flow one way like a check valve. The test in the FSM just tells you to blow in it and air is only supposed to come be able to be blown out of one side.
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Old Oct 6, 2004 | 02:07 AM
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Yea I was sucking air in from the tip, maybe I should try and push air out from the end..
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Old Oct 6, 2004 | 02:17 AM
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only on RX7club.com do we have people sucking on potentially hazardous materials


but anyways, if you think about it vacuum is smart. the MOP will open a certain amount and the main mechanism for ensuring oil flow is VACUUM. a lot better than pumping (positive pressure) or gravity by itself...of course it is hard to rely on vacuum unless you are dealing with a relatively small quanity that needs to be delivered, such as oil in this case
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Old Oct 6, 2004 | 02:25 AM
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Originally Posted by coldfire
only on RX7club.com do we have people sucking on potentially hazardous materials
All that time I spent laying in auto tranny fluid working on my 5spd swap w/o lift.

Extended exposure may cause cancer.


but anyways, if you think about it vacuum is smart. the MOP will open a certain amount and the main mechanism for ensuring oil flow is VACUUM.

The oil system is posetive pressurized. I was under the assumption the lines were pressure fed, and the VAC lines were to accomadate bleeding only?
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Old Oct 6, 2004 | 02:35 AM
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No, the lines (im pretty sure) go into the dynamic chamber and exit IN THE DIRECTION of incoming air, creating a vacuum. The other vac line on the dynamic chamber is a positive source, as its entrance connects up with the front of the TB, that little hole inside just before the butterflys, air flys into that, via vacuum hose, via the lower manifold.
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Old Oct 6, 2004 | 02:48 AM
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Originally Posted by BlaCkPlaGUE
No, the lines (im pretty sure) go into the dynamic chamber and exit IN THE DIRECTION of incoming air, creating a vacuum. The other vac line on the dynamic chamber is a positive source, as its entrance connects up with the front of the TB, that little hole inside just before the butterflys, air flys into that, via vacuum hose, via the lower manifold.
Lines before the plates aren't vac's. IIRC the only lines that go before the plates are fuel bleeds, oil bleeds, and bac(which is on the intake piping, not tb)?
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Old Oct 6, 2004 | 03:50 AM
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Originally Posted by Kenteth
All that time I spent laying in auto tranny fluid working on my 5spd swap w/o lift.

Extended exposure may cause cancer.
Dude i am so with you on that one. lol
In my hair, on my neck on my back just all freakin over.
and boy did i smell pretty when a girl came to see how the work was coming
Matt
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Old Oct 6, 2004 | 05:15 AM
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The oil nozzle vac lines do indeed have vacuum in them, but the air is flowing in the opposite direction to what most people think. The vacuum is coming from the engine side of the nozzle. The vacuum in the chamber itself sucks air through the oil nozzle. The rubber lines simply connect the nozzles to the intake ahead of the throttles so that only filtered and metered air enters the engine.

The extra air most likely helps "vapourise" the oil (not really the right word) in the same way the injector air bleeds help vapourise the fuel as it leaves the injectors.
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Old Oct 6, 2004 | 06:31 AM
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here how about this one

"atomizes"?

heh...

Thats intersting cause now that I read the manual again, and see the picture, it says that the valves should not be sucking in any air at all! Am I missing something?

They say that you should be able to pass air through the tip, to the part where the oil comes out, but not the other way around. huh?

maybe its becuase its 5:30am, I got to be at work in about 3 hours, and havent slept yet that im not getting this...
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Old Oct 6, 2004 | 07:39 AM
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Originally Posted by BlaCkPlaGUE
They say that you should be able to pass air through the tip, to the part where the oil comes out, but not the other way around.
That's exactly what I described above. Air is sucked into the engine through the nozzle during the intake stroke. The check valve is to stop combustion pressure leaking out during the power stroke.
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Old Oct 6, 2004 | 10:08 PM
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so, during intake air is pulled from the upper intake through the check valve andpushes oil through the fittings. then, aren't there contradictory vacuum forces on each side of the system? i know there's a check valve, but couldn't air more freely move/push out oil into the fittings if the lines weren't connected to vacuum on both sides?
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Old Oct 7, 2004 | 05:06 AM
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Air is taken from in front of the throttle, not behind it. There is no vacuum there.
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Old Oct 7, 2004 | 05:11 AM
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You people have no clue
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Old Oct 7, 2004 | 06:45 AM
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Originally Posted by MichaelFregoe
You people have no clue
... ok then
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Old Oct 7, 2004 | 11:41 AM
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Please, a list of the people that have no clue.
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Old Oct 7, 2004 | 12:08 PM
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Originally Posted by alexdimen
so, during intake air is pulled from the upper intake through the check valve andpushes oil through the fittings. then, aren't there contradictory vacuum forces on each side of the system? i know there's a check valve, but couldn't air more freely move/push out oil into the fittings if the lines weren't connected to vacuum on both sides?
Reading your first twenty or so words.....and I think you've got it. But then I read the rest of your words and ...nope, you don't have it quite right

It's what NZ stated.

If the engine was running, and you could pull the hose off oil injector spider, you would NOT feel any vacuum on the hose that comes from the direction of the throttle body. None, zip, zero, nadda.

If you then put your finger on the top of any of the oil injectors, you'd feel a vacuum.

The vacuum comes FROM the engine side of the oil injector. Caused by the intake stroke.

The hose that goes to the throttle body has no vac. Its path thru the throttle body terminates in front of the throttle plates. It's that quarter inch hole you see in the middle of the throttle body when viewing the throttle plates. Ain' t no vacuum there to speak of.

That's more or less what NZ said and I'm sure he said it better........but then again, maybe he's one of the people who have no clue! I gotta get that NO CLUE list so I can ignore any post made by them. humor, please.
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Old Oct 7, 2004 | 12:49 PM
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Attached Thumbnails Why do the oil injectors need vacuum to run?-oilinjectorbleednobvac.gif  
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Old Oct 7, 2004 | 06:55 PM
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lol, thats perfect.


Think about it people, injector air BLEEDS not injector air VACUME. Bleeding something usually implies realeasing it to atmospheric pressure,.. and if you have vacume before the throttle plates like some of you seem to think you have a SERIOUIS problem with your car.
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Old Oct 7, 2004 | 10:02 PM
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Originally Posted by MichaelFregoe
You people have no clue
NZConvertible is quite correct. The oil injectors (as well as the fuel injector bleeds) clearly receive fresh air from a nipple on the REAR of the throttle spacer plate. All nipples on that plate are FRESH AIR (non-vacuum) nipples.
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Old Oct 8, 2004 | 12:36 AM
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sorry, i didn't realize that the path of that nipple terminated on the intake before the throttle plates...
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Old Oct 8, 2004 | 01:10 AM
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alright then, i think I got it
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Old Oct 8, 2004 | 04:44 AM
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Kenteth, if you can't, don't...
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Old Oct 8, 2004 | 07:21 AM
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Originally Posted by Kenteth
All that time I spent laying in auto tranny fluid working on my 5spd swap w/o lift.

Extended exposure may cause cancer.
Wait, what...? What does laying in coolant do to you?
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