Vacuum Line Out

[Keggers]

Hi

I have discovered that one of my vacuum lines in behind the resonance flap seems to have come out. There is no vacuum coming to the solenoid valve next to the alternator, so I traced the line back and noticed that it joins a three way connector behind the resonance flap pipe. The line from the solenoid valve is plugged in fine. The second connector seems to go to the vacuum cannister. The third connector seems to have plugged nothing in it. Its very difficult to see clearly in there as to whether there is a loose line hanging around there that should be plugged into the connector.

So I have two questions:

1. What impact will having no vacuum coming through this line (and the vacuum cannister being unable to create a vacuum due to the open connector) on the running of the engine?

2. Is there an easy way to get in there to access the connector without removing the throttle and the two pipes? I've done this before to install my PSE (which is probably when I knocked the line out!!) and it was a very hard job to get the two pipes back on.

Its a 1998 Carrera in Irish spec.

Cheers

Greg

[996noob]

Hi

I have discovered that one of my vacuum lines in behind the resonance flap seems to have come out. There is no vacuum coming to the solenoid valve next to the alternator, so I traced the line back and noticed that it joins a three way connector behind the resonance flap pipe. The line from the solenoid valve is plugged in fine. The second connector seems to go to the vacuum cannister. The third connector seems to have plugged nothing in it. Its very difficult to see clearly in there as to whether there is a loose line hanging around there that should be plugged into the connector.

So I have two questions:

1. What impact will having no vacuum coming through this line (and the vacuum cannister being unable to create a vacuum due to the open connector) on the running of the engine?

2. Is there an easy way to get in there to access the connector without removing the throttle and the two pipes? I've done this before to install my PSE (which is probably when I knocked the line out!!) and it was a very hard job to get the two pipes back on.

Its a 1998 Carrera in Irish spec.

Cheers

Greg

Theoretically, the Y connector should be connected to 3 things which are; vacuum reservoir, switchover valve, vacuum source. Since you have traced the connections of the Y connector to the first two mentioned, then what you are probably missing is the vacuum line to the vacuum source at the left or right rubber sleeves which connect the air intake T-piece after the throttle to the left or right intake manifolds.

Somewhere along this vacuum line, you should also have a one-way check valve.

From memory, I believe you need to take out the throttle body and all that stuff to get access to the Y connector behind it.

Your engine will not run well without the vacuum line connected. 1) you will have a vacuum leak. 2) your reserevoir will not get a vacuum accumulated 3) your resonance flap will not move.

Hope this helps.

Edited March 27, 2010 by 996noob

[Keggers]

Thanks 996noob. Sounds like I need to get in there and reconnect it.

Just out of interest, will this make any difference to my mpg?

[Keggers]

Bit the bullet this morning and removed the throttle and the first of the two intake tubes behind the throttle. Took me a while to work out where the empty connector was meant to connect to. Couldn't see any loose pipse to plug into it. Ended up burying my arm in well past the elbow into well behind the vacuum cannister and found that the solenoid that controls the vacuum valve on the cooling system under and just in front of the engine had only one vacuum line connected onto it. There was no pipe on one side of it at all (just like on the three way connector). Had some spare pipe so connected it up, put it all back together again and it seems to have solved the problem. Idle speed is back to bang on 700 rpm and it seems to be holding a vacuum now.

So it appears that this vacuum line has probably been missing since before I got the car and the problem has probably been there the whole time that I've had the car. It will be interesting to see if it runs any better now. Presumably this will be the first time that the resonance flap has worked since I got the car, as there previously was no vacuum supply to it. I don't know if it makes much difference but I guess I'll find out!

One follow up question though. I noticed there was a fairly heavy lining of oil inside the intake tube that the throttle connects onto. Is this normal or is it a sign of another problem?

Cheers

Greg

Edited to add that it was overfilled with oil slightly for a week or so late last year after its annual oil change. I ended up draining out about 500ml of surplus oil. I wonder if this might be related to the oil in the intake?

Edited March 28, 2010 by Keggers