vacuum pipe identification

[scotlan]

I have a severed Vacuum pipe hanging free. As can be seen in the photo it is shown running from front to back of the pic. it clips to the bulkhead and then goes across the bulkhead and then through it with a similar diameter pipe.
My questions are: What does it do? where does it start from at the manifold? is there a required union to attach it to and what diameter is it?

The answer to one or more of these questions would be appreciated

[lotustonybassplayer]

it goes to the vacuum reservoir behind the wheel arch liner. it starts from the rocker cover right hand side at the rear just in from the corner you should see a little spout where it connects to. It usually has a right angle rubber connector, i've just replaced mine it comes from a mini distributor £1.75 on Ebay part no 12B2062

[scotlan]

it goes to the vacuum reservoir behind the wheel arch liner. it starts from the rocker cover right hand side at the rear just in from the corner you should see a little spout where it connects to. It usually has a right angle rubber connector, i've just replaced mine it comes from a mini distributor £1.75 on Ebay part no 12B2062

Lotus base player, thanks for your input. I should have said, I have 2 severed pipes. One is that which you refer to, the other heads in the opposite direction, effectively from the passenger side to the driver's side along the bulkhead. It has a smaller diameter, it is this one I am needing help with.

[GeoffSmith]

Possibly the heater valve.

[scotlan]

Possibly the heater valve.

Geoff, thanks for your reply, I thought you'd hit the nail on the head so I went to check. There is one vacuum pipe attached to the valve which is in tact. My severed one meets up with that one on the bulkead and travels with it until they both go through the bulkhead one slightly above the other.

I attach a new picture it's the one sealed with tape.Thanks

[johnj]

I think that if you look almost directly down from where the end of the broken hose is, there is a Y shaped hose. If you follow the Y back towards the bulkhead there us a circular metal 'thing' (sorry not mechanic'). It has a nipple at the bottom. I think the pipe connects there.

[scotlan]

I think that if you look almost directly down from where the end of the broken hose is, there is a Y shaped hose. If you follow the Y back towards the bulkhead there us a circular metal 'thing' (sorry not mechanic'). It has a nipple at the bottom. I think the pipe connects there.

Thanks JohnJ. I have checked what you described, found the Y hose and followed it back to the bulkhead but I'm unable to identify the circular metal thing you mention.
I have a friend with an S2 who lives a couple of miles away... as soon as lockdown is over I will look at his to see if I can follow up on what you suggest.

[johnj]

See attached picture, bottom hand pointing to the Y hose. Top hand pointing to the metal piece with tube attached.

Hope this helps.

[scotlan]

See attached picture, bottom hand pointing to the Y hose. Top hand pointing to the metal piece with tube attached.

Hope this helps.

First, I must thank you for showing me by taking the picture. You must have gone to some trouble as both of your hands are in the picture!
However this pipe is in place and intact on my car. The pipe which I am trying to identify comes out of the bulkhead right next to "yours" and then across the bulkhead and I don't know where it should end up.
Thanks again

[dapinky]

Here are a couple of pages from the workshop manual, and a photo of my old engine bay (without engine) which may help you to trace what you have, and what is missing/broken/detached.

heater pipes.jpg

throttle vacuum pipes.jpg

engine bay.jpg

[GeoffSmith]

It runs from the heater unit to the vacuum reservoir in the wing.

[scotlan]

Here are a couple of pages from the workshop manual, and a photo of my old engine bay (without engine) which may help you to trace what you have, and what is missing/broken/detached.

It runs from the heater unit to the vacuum reservoir in the wing.

First dapinky: Thanks for the engine-out photo. Starting at the lower red heater pipe, looking at the picture, there is 2" to the left of it, a small vacuum pipe that goes through a grommet and through the bulkhead. In you picture I can't see a second pipe 1" above the first. One goes to the heater valve the other then travels along the bulkhead and clips to the electrical control box to the left of your alarm.

second: GeoffSmith

It runs from the heater unit to the vacuum reservoir in the wing.

[/quote]

Yes, it could well go to the reservoir. I think from the information you both have given me that it is Pipe No 2 on diagram 14c. I also have another severed pipe which comes from a union on the manifold. I believe this also goes to the reservoir and should have a non return valve on it.

I now need to get the inner wheel arch off to see where these two pipes go. Maybe they were severed at the same time before I owned the car. I think the two pipes have different diameters, would that be correct?

[GeoffSmith]

Red and blue pipes both go to the reservoir - no non-return valve as far as I can remember.

[scotlan]

Red and blue pipes both go to the reservoir - no non-return valve as far as I can remember.

I think I am right in saying that the "blue" pipe attaches to the elbow at the inlet manifold

Very grateful for your help as up to now it's been a mystery!

[roy666]

Hi Scotlan.. I had (have) exactly the same issue..looks like. Gerald at GST Performance just plugged the pipe up for me saying it was redundant. No isues from it since. cheers Mike.

[scotlan]

Hi Scotlan.. I had (have) exactly the same issue..looks like. Gerald at GST Performance just plugged the pipe up for me saying it was redundant. No isues from it since. cheers Mike.

That's interesting Mike and exactly where mine is severed. It wasn't plugged til after I bought it. So, I have a question, what effect does it have on the heater operation, that the reservoir isn't connected? Tony

[dapinky]

Mike (and Tony),

The pipe which Gerald has plugged may well be redundant on yours - there are 2 nipples next to each other on the back of the inlet manifold - 1 has the black elbow attached and goes to the reservoir (and needs to be fitted to allow heater to function)....

.... the 2nd one is usually 'capped' when the car leaves the factory. (I assume that it had a specific function when the engine was used elsewhere, but not needed on an Elan).

This 2nd nipple needs to be capped (or in you case, a pipe fitted and plugged!) so that there is no vacuum leak which will affect the sensors for the engine management.

However

I would suggest that (judging from the length of pipe, and where it ends up) that someone previously has had a dump valve fitted, and used the 'extra' nipple to activate it, instead of fitting a 'tee' piece in another vacuum pipe.

[scotlan]

Mike (and Tony),

The pipe which Gerald has plugged may well be redundant on yours - there are 2 nipples next to each other on the back of the inlet manifold - 1 has the black elbow attached and goes to the reservoir (and needs to be fitted to allow heater to function)....

.... the 2nd one is usually 'capped' when the car leaves the factory. (I assume that it had a specific function when the engine was used elsewhere, but not needed on an Elan).

This 2nd nipple needs to be capped (or in you case, a pipe fitted and plugged!) so that there is no vacuum leak which will affect the sensors for the engine management.

However

I would suggest that (judging from the length of pipe, and where it ends up) that someone previously has had a dump valve fitted, and used the 'extra' nipple to activate it, instead of fitting a 'tee' piece in another vacuum pipe.

Dave/dapinky Thanks for your input. I feel I have identified one of the two severed vacuum pipe as the one that goes from the elbow on the inlet manifold to the vacuum reservoir. The second one which prompted this post I now believe is the pipe no 2 from diagram 14c also going to the reservoir.
So I am now a bit confused as to what the second outlet pipe from the inlet manifold is for. Does this pipe go the purge line as shown in diagram 02 on this post? This pipe drops down behind the engine and disappears, can be seen in the second pic from the back of the engine.

[scotlan]

Yesterday, ALL the engine-side vacuum pipes were replaced. I knew there was a vacuum issue as a pipe from the manifold had been severed and I had previously temporarily plugged it with a screw.

However the result was nothing short of AMAZING!

Before: the tickover was a bit high and erratic, there was a bit of a flutter when driving at low reves, performance seemed OK
After: Smooth tickover, no flutter, smooth drive and above all a truly massive boost in acceleration!! I just couldn't believe it. Also the original reason for replacing the pipes, my heater control now operates for the first time since I bought the car.

I bought the pipes, 2metres each of 2 different diameters and some joining connectors for £15. The best £15 I ever spent on a car!

[Kipperozzy]

Well done Scotlan, for fixing your issues on the cheap and updating the results