Author Topic: Random vac pipe  (Read 4653 times)

Offline tony_ack

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Random vac pipe
« on: 26 June 2010, 10:25 »
I took the inlet manifold off my 16v KR to change the cam cover gasket. Now I'm putting it back together, and I seem to have a random vac pipe left over and I can't see what it connects to.

Any idea what this is?



It seems to run from the overrun cut-off. The overun cut off is connected to a T-connector, which is in turn connected to another t-connector. This T-connector has a feed to the brake servo pipe, and then this random pipe.

I can't see anything on the inlet, throttle body or air intake that this could connect to. All the pipes on the intake boot are connected, except the big one that connects to the overrun cut off.
1992 VW Golf MK2 GTI
1995 VW Corrado VR6

Offline raferackstraw

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Re: Random vac pipe
« Reply #1 on: 26 June 2010, 11:08 »
is that not the one that connects to underside of intake boot just before the throttle body?

wayne gardner smokes one rothmans too many
500cc 2stroke bad for ya health

Offline tony_ack

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Re: Random vac pipe
« Reply #2 on: 26 June 2010, 11:22 »
Nope, that's already accounted for - that one comes from the first t-connector

I've just put everything back together again and started the car up with that disconnected and it seems to run okay-ish, revs fluctuate a little when I block it off with my finger, but only just.

Maybe it's supposed to be blocked off? Could it be why the car is running rich?
1992 VW Golf MK2 GTI
1995 VW Corrado VR6

Offline raferackstraw

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Re: Random vac pipe
« Reply #3 on: 26 June 2010, 11:44 »
just had a look at mine and from the t connector to the overrun a pipe goes to a small diaphragm type thingy that is attached to the airbox

wayne gardner smokes one rothmans too many
500cc 2stroke bad for ya health

Offline raferackstraw

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Re: Random vac pipe
« Reply #4 on: 26 June 2010, 11:53 »
ok had another look, i have 2 outlets on the servo pipe 1 vac hose goes to ecu. 2nd vac hose goes to t piece no1, from t piece no1 1 goes to clocks and other goes around back of manifold to t piece no2 under throttle, from this no2 t piece 1 vac goes to intake boot under throttle body, the other goes to a no3 t piece of which 1 vac goes to overrun valve and the other goes to that diaphragm thingy on airbox
that is all vac hoses on my kr  :wink:

wayne gardner smokes one rothmans too many
500cc 2stroke bad for ya health

Offline tony_ack

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Re: Random vac pipe
« Reply #5 on: 26 June 2010, 12:15 »
Thanks for taking a look!

Looks like I have one t-piece more.

All the pipes you mentioned are present and accounted for, I just have this mystery pipe left over!

I've blocked it with a screw for now..
1992 VW Golf MK2 GTI
1995 VW Corrado VR6

Offline tony_ack

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Re: Random vac pipe
« Reply #6 on: 26 June 2010, 12:17 »
Actually, no, I've just realised!

On mine the intake boot connects directly to the airbox, it doesn't go via another t-piece. So that's where the extra pipe has come from!
1992 VW Golf MK2 GTI
1995 VW Corrado VR6

Offline tony_ack

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Re: Random vac pipe
« Reply #7 on: 26 June 2010, 13:32 »
Hmmm.. come to think of it, that isn't it either... I'm still one connector short. I've added some notes to the original diagram to see if that helps. I've blocked it with a screw for now. As far as I can tell, everything on the car works.

I've accounted for the feed to the t-connector near the servo pipe, the two pipes on the intake boot, the pipe to the overrun cut-off and the airbox diaphragm. Surely there's nothing else around there it can connect to?

1992 VW Golf MK2 GTI
1995 VW Corrado VR6

Offline raferackstraw

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Re: Random vac pipe
« Reply #8 on: 26 June 2010, 13:52 »
to clocks mate? have you got a white plastic pipe hanging about near the scuttle panel?

iirc didnt some later kr airboxes have an additional vac hose connection on intake boot on metering head?

wayne gardner smokes one rothmans too many
500cc 2stroke bad for ya health

Offline tony_ack

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Re: Random vac pipe
« Reply #9 on: 26 June 2010, 15:13 »
The clocks pipe is connected as I'm getting an MPG reading.

All the connectors on the intake boot and top half of the inlet manifold are 'wired' in correctly - they all have pipes connecting to somewhere.

I guess this is going to be one of those small mysteries of life. All I can think is that in the past someone has put the pipes back the wrong way, which has left this one loose.

I took it for a test drive, and it seems okay, a little smoother if anything, it smells less rich and mpg was up a little, but power felt a touch down. Could probably do with the CO re-setting now.
1992 VW Golf MK2 GTI
1995 VW Corrado VR6