Hi Everyone,

Well here is my first question for everyone, and I hope it is not an inconvenience. On my 93 FD I have an open hose on my air pipe control valve, it is part 2 on page C26 of the workshop manual, the Y shaped part. The upper nipple of that part has a hose about 4 cm long that goes no where. It also seems to leak a little air, Does anyone happen to know where this hose should go? With the length of hose on it, it can not be far away, yet there is nothing anywhere close that it could go to.

Any help would be awesome!


Mike

 

not to sure about FD but my 1990 FC has a hose coming out the side of the ACV that routes to under the right front headlight goes throug a silencer and just outputs to air. on fc's the ACV gets air from the air pump and determines wether it needs to go to the main cat, or to the fith and sixth ports, or silence it and vent it to the air.

anyone correct me if i am wrong.

 

Originally there was another hose about a foot long with a 90o elbow that went on the nipple, the other end went into the ABV (Air Bypass Valve aka blowoff), the short piece of hose that appears to be on the nipple now was used to connect the ABV to the stock airbox.
The vacuum line to the ABV connected to a nipple on the upper intake.
If an after market blowoff is being used the short hose may have been used to hold a plug, if not the ABV is missing.

 

Thanks 93 and datz, Well there is no aftermarket BOV on my as of yet, but I have been looking for the Air Diverter Valve and can not find it, this would be why! So I guess there would be air blowing out of this hose while the car is under boost? as there is no diverter valve blocking it?
Can I plug it for now until I can find a diverter valve? or would it be a good idea to just leave it?
Hmm might be a good excuse to talk the Mrs into letting me spend some more money on the car for a BOV

Mike

 

im pretty new to this and all that i have been figuring out is fc's.

does the hose blow air out or suck air in?
if it blows out I would just leave it how it is(maybe get a longer hose so it vents under the ex manifold. and if it sucks in air i would probly plug it and see how the car runs.

 

I am going to try plugging it off tonight when I get home Datz, I am also going to try revving the car right up and seeing if it releases any air. I am wondering if there is maybe an internal control, I will post and let you guys know tonight.

 

Alright so at idle it maybe has just a small amount of air coming out of it, but at mid rpm the air starts to pick up, then at full rpm the amount of air is quite a lot, like it moves your hair after it bounces off your hand. I am thinking could it be the diverted valve for the 2nd turbo? just missing the valve itself.
Any thoughts would be appreciated.

 

If it's for the bypass valve/stock bov as mentioned, having it uncapped is creating a big vaccum/metered air leak. For one, unfiltered air could be sucked in at idle. Besides that, it will cause a boost leak under acceleration. Is the car making full boost?

 

I would have to say that it is not making full boost, but I will have to wait as I have some Prosport Gauges on the way for the car, there is a Sard gauge in the car but the readings it is giving off seem kind of strange, they are always in the negative. I did find that the sard boost gauge/controller main vacuum/boost tubing is leaking so that might account for some strange readings. (noticed while i was taking out cpu no2 for a different problem). Maybe I will block the port off for now and see if my boost readings change. I will keep you all posted

Mike

 

Do not plug it and run the engine without a bypass valve. When letting off the gas while making boost, pressure will build behind the closed throttle plate and push back through the turbos if there is not ABV in place to vent off the pressure and protect the turbos and engine.

Post a photo of the entire engine bay. here may be a ABV somewhere else on the intake piping.

 

You can buy a used stock ABV for under $20. I would buy one and plumb it exactly per the vacuum diagram. Do not plug it as mentioned or else it will hammer on the turbos. You need to do something, because it's currently sucking raw unfiltered air directly into your engine.

I recommend you look through the vacuum diagram carefully to see what else the previous owner left all f'd up for you.

Dave

 

Ok I will unplug it, I can not drive the car right now anyways seeing as there is ice and snow everywhere.

93 I know there is no BOV anywhere else on the car, there looks to be a stock air diverter valve on the rear turbo that is plumbed into one of the intake pipes.

dgeesaman I have looked at the vacuum diagram and started looking under the hood, there are ALOT of plugged of lines.
where can i find a used stock BOV? non of my local (within 300km ) auto wreckers even have an RX7 in the yard. Rare car up here lol I will try to get some pics for you guys asap I am just on lunch atm


Thanks

Mike

 

Ok I managed to get some pics before I i gotta go back,
BOV that is on the rear turbo (U can see that piece of blue tape on the UIM... there was no plug on that either which makes me think thats where the other BOV hooked up.



Full under hood pic



and for dgee a small fraction of the plugged vacuum lines lol

 

I think for now until I can find a Diverter valve I will get a length of hose and run that nipple up to the intake pipe just behind the air filter, that way the air is at least filtered, I was taking a quick look on E-Bay at some 20 dollar billet aluminum BOV's just something to put on there until I can get a good one.

 

The exit of the second BOV (charge relief) goes back to the stock air filter box, which has been removed in your car. The first BOV should also go back the air filter box.

The plugged vacuum line is (I think...) supposed to go to the pressure chamber, which you lack. Following your plugged line the other way it should end up in the turbo control solenoid. Maybe your 7 isn't sequential anymore? The pressure chamber could have been relocated also..

 

I am thinking you may be right and my 7 is not sequential anymore, I did not have the time tonight to map out what vacuum lines are still in the car and my boost gauge is not here yet or I would know I think. If my 7 is not sequential anymore my boost would stay steady at 10psi correct? there would be no dip at the 4500 rpm mark. I am going to do some research on non sequential setups tonight.

Mike