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Discussion Starter #1 (Edited)
Hi again!

I've been tracking down a vacuum leak, and I noticed in the vacuum diagrams that the leveling system for the headlights uses vacuum from the PSE pump. I test the leveling system and: it doesn't work!

I take a quick look: the vacuum pipes aren't even connected, just taped over with insulating tape (which would never be airtight for vacuum to build up). I take the tape off, and try to fit the pipe back on the nozzles on the headlights, but they somehow don't fit. Or can't "click" on at least.

Thing is, the headlights have been fitted with xenon lights, and the guy I bought it off, told me he had fitted clear lenses..

Now, I have tried googleing it, but I can't seem to come up with a clear answer to the following question:

Is there something about xenon (HID) lights that requires you to disconnect the leveling system? Why else would the previous owner disconnect it and tape it up? Why don't the pipes fit with the nozzle anymore? :(

As always, any help would be greatly appreciated. You guys are awesome! :)



::As a side note:: I tried putting small plastic bags over the ends of the pipes and taping them airtight shut. Didn't fix the vacuum leak, so it's somewhere else either on the engine, transmission or A/C flaps :s Think I might be out of my league on this problem. Everytime I accelerate the PSE pump is working like crazy, then stops if I just keep the speed constant. The PSE pump does nothing if the car is in idle. Is that indicative of the transmission or is it just misleading? The car has quite a rough idle..
 

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This is interesting. I didin't know that the self leveling on headlights is using vacuum. Can you send the link to the article where you read it?

My 97 S420 has only electrical connections. I just recently took both lights off I didn't see any vacuum lines, then again there's no telling that they weren't there. The lights are moving whey I turned them on, trying to self level, which I don't think really works. They were too high I had to manually adjust them.
 

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Yes, and its what the OP suspect. Since OP has a 1991, it was not xenon original.
Non-xenon uses the tumbler switch (similar control to the switch for the orthopedic
backrests) to control leveling (not automatic).

I guess the installer of your xenon did install it without the (for norway at least) mandatory self-leveling system (sensor on each sway bar, and a control module).

br,
syljua
 

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::As a side note:: I tried putting small plastic bags over the ends of the pipes and taping them airtight shut. Didn't fix the vacuum leak, so it's somewhere else either on the engine, transmission or A/C flaps :s Think I might be out of my league on this problem. Everytime I accelerate the PSE pump is working like crazy, then stops if I just keep the speed constant. The PSE pump does nothing if the car is in idle. Is that indicative of the transmission or is it just misleading? The car has quite a rough idle..
As for your vacuum leak, (from the PSE point of view) I would bet on the
feed to the plenum that assist the AC. Normal feed of vacuum to this is done
from the engine intake. Since you also have a rough idle, I would guess that you have false/
un-metered air entering the intake.

As, if I'm not mistaken, you will have less vacuum (higher pressure) in the intake
upon acceleration, and that will cause the PSE to try to "help" out.

Now, how the pump knows, I'm not completely sure, but I think it will "suck" until
a certain level of under-pressure is achieved. As such its doing its right thing,
and might just be operating correctly, though if you have a leak in the intake out
to atmosphere it will run more often than normal.

So, to refer to this vacuum diagram, I would guess that it is in one
of the components connected to that "ventilblock" under the passenger footwell;
B91F1243

br,
syljua
 

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Discussion Starter #6
As for your vacuum leak, (from the PSE point of view) I would bet on the
feed to the plenum that assist the AC. Normal feed of vacuum to this is done
from the engine intake. Since you also have a rough idle, I would guess that you have false/
un-metered air entering the intake.

As, if I'm not mistaken, you will have less vacuum (higher pressure) in the intake
upon acceleration, and that will cause the PSE to try to "help" out.

Now, how the pump knows, I'm not completely sure, but I think it will "suck" until
a certain level of under-pressure is achieved. As such its doing its right thing,
and might just be operating correctly, though if you have a leak in the intake out
to atmosphere it will run more often than normal.

So, to refer to this vacuum diagram, I would guess that it is in one
of the components connected to that "ventilblock" under the passenger footwell;
B91F1243

br,
syljua
Awesome! Thanks for the help, gonna check out the plenum, see if there is something wrong there. Good to get it explained, maybe gonna have the MAF checked..

And there is something seriously wrong with the headlights, can't manually adjust them, and the left one is pointing considerably lower than the other :s

Again, thanks for your reply Syljua!
 

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Yes as the other replies.

The PSE pump under the seat does the locking, seats and AC and helps out in the engine end where needed.

It is important that this pump does not run too long or it will burn the pump motor out, with no leaks it only runs for about 5 seconds at a time when all good.

Re the lamps, there is no provision for the engine controlled vacuum pipes and they should be blanked off . Xenon lamps should be levelled by a sensor on the front and rear axles, sadly these never get fitted with after market lamps. You will have the manual adjusters built into the lamps, the inner holes do the up and down and the out holes the side movement
 
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