Vacuum Line Goes Where?

[Fourdoorcat]

I managed to disconnect this vacuum line and can't seem to figure out where it is supposed to go. This is a US spec Elan. Can someone guide me to the right spot?
Thanks!
Ken

[Fourdoorcat]

I found some more information but, so far, it doesn't help. According to the workshop repair manual (V2), p14d: This goes to "the left hand port (marked "vacuum") on the vacuum reservoir mounted at the rear of the left hand wheelarch". Two things are confounding me: 1. the length of the hose seems too short to go where the manual says and 2. Even after sliding the overflow tank out of the way, the only thing I see down there is the coil pack. Not a "vacuum reservoir" in sight. I am guessing that if this information is correct, there must be a junction of some sort that completes the connection to the vacuum reservoir.

Any help is appreciated!

Thanks,

Ken

[Brit-Car-Nut]

The vacuum reservoir is inside the wheel arch. You can remove the plastic liner and you get to see the reservoir and Brake Master Cylinder easily.

It is possible that someone has added a "Tee" to gain another vacuum port. Look at service manual V6, section PE page 15 or PDF page 487 to see that the line going to the resevoir is for the heater/AC control vacuum system.

The OTHER line goes to a check valve along the firewall before routing the purge line to the charcoal cannister behind the fuel filler area. Section LG, page 20 or PDF page 460.

You can download the V6 manual at www.lotuselanm100usa.info/manuals

This copy doesn't have the watermarks.

[Fourdoorcat]

Thanks, John.

The car is stock and driven daily. I found this troubleshooting a vacuum leak that was causing the air from the interior vents to shut off when driving up a long hill. Backing off the throttle immediately restored the flow. The hose and the relationship to the vacuum reservoir all make sense. It seemed a matter of merely slipping the hose back on (and probably running a new length as well). The hose is about a foot long and the reservoir has got to be about four feet away. So it doesn't connect directly.

I think what would help is if some kind person would open their hood, see where this hose connects and either describes it to me or (better yet) posts a picture. I am certain I will feel like and idiot when the answer to this turns out to be dead simple. At least I will be an idiot with things working again!

Regards,

Ken

[superbad]

Thanks, John.

The car is stock and driven daily. I found this troubleshooting a vacuum leak that was causing the air from the interior vents to shut off when driving up a long hill.

I don't think that's necessarily a vacuum leak. If you've got the throttle open and the engine is making boost, eventually it's going to turn the vacuum in the manifold into positive pressure.

[Fourdoorcat]

Superbad,

I had exactly the same thought, before I discovered the vacuum reservoir. Since boost is a transient event, I suspect we would all be experiencing a lack of flow from the vents everytime we put our foot into it. The vacuum reservoir is likely designed to provide vacuum during these boost periods where vacuum is absent. It probably has a one way valve incorporated in the design so that positive pressure during boost is not allowed to deplete the vacuum.

All that being said...do you know where this hose terminates? I'm still searching!

Thanks,

Ken

[superbad]

Thought about that after I posted. There should be a one way valve into the reservoir, but the service manual makes no mention of it. It's been a while since I swapped my lines out, but I don't recall seeing one. They might just be relying on the reservoir being large enough to withstand the small amount of boost that leaks in through the little supply line, and of course that would be overwhelmed on a long high boost run.

According to the service manual, the line you pointed out should go to the reservoir. The one below it goes to the secondary throttle actuator.

[Fourdoorcat]

Thanks, Superbad.

The line will eventually get back to the vacuum reservoir, but it was connected (as of yesterday) to some point about a foot away from the fitting on the intake manifold. This is the part that is driving me crazy.....I can't find that point. Perhaps it was an in-line connector and the other part dropped away once it disconnected.

If I put the car up on jackstands, remove the driver's side wheel, maybe remove the fender liner, I should be able to see the vacuum reservoir and the two lines that connect to it. From there, I can follow the line that goes into the engine compartment and, eventually, locate the disconnected point (kick myself for not seeing it sooner), reconnect it, put everything back together and be on my way.

Seems like a lot of effort but I guess that's what I will have to do to get this resolved. Oh....I suspect that the one way valve (if, as you point out, there is one) is built into the reservoir. When I finally find that %$*&(* connecting point, I may try a little pressure and vacuum on the line to see if this is so.

Ken

[Brit-Car-Nut]

Looked at mine and the line goes diagonally toward the firewall and driver side fender. It then follows the firewall to the vacuum canister. Way too congested to get a good picture. No cuts, splices or check valves.

[Fourdoorcat]

Thanks so much for doing this, John. I plan to dive into it again this evening. I bought some new hose today since the end of the one that came off was somewhat (I love this word) knackered.

I still have this "long vs. short" hose issue (i.e. the one that came off is only about a foot long). When I sort this out, I'll post whatever I find.

Ken

[superbad]

Fender liner definitely has to come out to get to the reservoir. Are you sure your line hasn't just perished and broken in half somewhere along its length? Are the heater controls still working?

[Fourdoorcat]

Well....more progress. With the overflow tank pushed to one side, you can see the vacuum reservoir. Even though the manual says differently, the tubing end I circled in the picture does not go to the vacuum reservoir. The one next to it most definitely does; following the same path John described. Let's face it: the vacuum from the manifold doesn't much care which line is which.

What the manual tells me is that the other line goes to the "second throttle vacuum reservoir". Using my handy dandy inspection camera, I was able (with some difficulty) to find this component on the backside of the engine, below the intake manifold and verified that the two vacuum lies that go into it are present on the component itself. This means that the connection to the manifold gets picked up someplace else.

I'm out of time tonight. Perhaps I can beg John to see where the other line goes and report back. This is the one that is about a foot long. Even with the knowledge I now have, I still don't know where the fitting is located. Next course of action (unless someone can tell me where it is) is to try and follow the hoses from the second throttle vacuum reservoir. One goes to the second throttle vacuum solenoid valve; that's not the one I want. All of this is easy to say but, as everyone knows, it's not easy to find your way around back there.

Superbad: all the heater and A/C controls work fine. That bit of information (along with John's comment) led me to believe that the vacuum reservoir was still connected. When I go up the long hill, the reservoir is probably less full of vacuum than it should have been due to the leak in the open line. Once I get it reconnected again (and replace the line as well), I expect that problem to be resolved.

I think, as the Fab Four once said, "We're getting nearly to the end".

Ken

[tigerdog]

If you haven't downloaded the full compliment of manuals, it's worth doing so. Here are a couple of diagrams from the closed-loop manual:

Vacuum secondary components and routing

Given the length of the tubing, it seems like it must either feed the EGR or secondary system. Hopefully the diagrams will help.

[dapinky]

I appreciate that the Fed version may well have different bits than the Uk version, but here is a pic of my engine bay whilst i was swapping out the vacuum lines during an engine swap. I can't remember exactly what went where (it was a number of years ago), but the new lines are blue and there are still some of the original black ones in the picture.

It may be of no use at all, or it may show you the routing of some of the pipes you need to look for.....

[Mike_H]

I think that vacuum pipe goes to the vacuum reservoir positioned on the inside of the wing .

I hope these two pictures help.

Mike.

[epipete]

Love the sledgehammer in the picture, it's exactly the way I feel at the moment!

[epipete]

Love the sledgehammer in the picture, it's exactly the way I feel at the moment!

[Fourdoorcat]

I determined that this disconnected line has nothing to do with the vacuum reservoir for the climate control system. So that is ruled out.

This image applies; the highlighted tube is the path that appears to be open.

The vacuum reservoir for the secondary throttle is well hidden in the back of the engine. However, I was able to determine that the two vacuum hoses shown in the diagram are attached. Apparently, there is an inline connection someplace that accepts the hose which starts at the intake manifold and travels about 12". This is what the unconnected hose looks like:

My problem is I cannot determine where the hose connects.

I have all the manuals. Thanks for all the help. Sorry if I am not explaining this very well.

Ken

[Rice crispy]

do you have a dump valve? if so then there is a vacuum connection to that.

[dapinky]

For some reason my pic didn't display so I've edited the post - - - but then again, the picture from Mike probably shows more useful stuff.