Headlight level adjuster vacuum leak = loss of power!!???

[Mohnish]

Hello again,
Stumbled upon an interesting observation, or was this a co incidence...?
The headlight level adjuster (the rotary switch near the headlight switch) had no effect in the level of the lamps, so decided to look into it. Found that the previous owner had (reason unkown) disconnected and plugged the vacuum lines into both the headlights. I reconnected both lines to the headlights and they still did not adjust. Being short of time, decided to look into this later.
About 15 minutes into my next drive out, there was a complete loss of power, no acceleration, similar to a dead turbo. Decided to check on the recent vacuum lines I had fiddled with and on checking, I found that the vacuum line connecting to the right head light had come off. (I probably had not set it deep enough) Reconnected it and the power comes back again!!! Wierd???
So my queries are :
1. Is there any connection between headlamp level adjuster vacuum line leak and loss of power ?
2. I have been given to understand there are 4 vacuum systems as follows:
(a) Headlamp level adjuster
(b) Central locking
(c) Automatic transmission shift
(d) Turbo actuator/wastegate
Is the above correct and if so, are these inter related ie. can a leak in one system result in malfunctioning of the other?
3. There is a hissing sound coming from the area of the headlamp level adjuster rotary switch after reconnecting the vacuum lines to the headlamps. It was not there when the lines were disconnected and plugged. I know this hiss is not 'normal', its obviously a leak. Could this be the reason for the non functioning of the headlamp adjustment?
I am attempting to solve this tomorrow, so would be greatful for any inputs and help.
Thanks in advance.

 

[Dieselman]

The hissing does sound like a leak and possibly the headlamp adjusters are leaking as well.
Ultimately all the vacuum is supplied from the vacuum pump so a sizable leak might reduce vacuum to the turbo or more likely the EGR modulator, thus causing the limp home operation.

 

[Mohnish]

The hissing does sound like a leak and possibly the headlamp adjusters are leaking as well.
Ultimately all the vacuum is supplied from the vacuum pump so a sizable leak might reduce vacuum to the turbo or more likely the EGR modulator, thus causing the limp home operation.

Thanks Dieselman...That answers all my queries!
EGR = Exhaust Gas Regulator = The pressure regulator that drives the turbo? Is this correct?

Your post leads me to understand that the EGR is activated by a single vacuum pump. Wouldn't it be more reliable to use a mechanical or inlet manifold driven pump to drive the EGR instead of relying on an electircal pump that could fail? I presume it is the same electric pump that creates the vacuum for the central locking etc. that is used to drive te EGR?

So for today, I must identify the leak. Probably at the switch or at the headight adjuster connectors or both. Will also lift out the rear seat and check all the connectors/lines at the pump.

While on topic, sometimes (not from a dead stop, but when say cruising at an rpm of 1500 and you step on it) there is a delay in the power, a delayed response on acceleration. I thought it was probably the way this engine was setup to behave, not having driven another to compare. But now I am inclined to think this is a delay in the EGR response.

Again, thanks for your response...Will post later today after I do the above.

UPDATE:

Disconnected the vacuum lines from the headlamps and plugged them shut. The hiss went away and also the power response was immediate. So there is a definite connection between vacuum leak in the headlight adjuster and the power, as Dieselman said, "more likely the EGR modulator".

Reconnected the vacuum lines to the headlamps and they do adjust ever so slightly...not at all adequate and the hiss returns and the power drops off...So, as Dieselman correctly said, "the headlamp adjusters are leaking as well..."

So now, I figure, instead of repairing/replacing the adjusters, I may as well realign the entire headlights to point at the correct level and leep the vacuum lines disconnected.

Thanks again Dieselman, you were correct on every point.

 

[Mohnish]

Further...

I have found that the left headlight vaccum system leaks. Tried to remove it and it is a press and turn fit, however there seems to be a couple of holding bolts that can only be accessed after removing the glass. Am I correct?

So instead of going through the process, since I prefer to set the lghts at the upper most position, I manually adjusted (adjuster knob) the reflectors to point at the highest point.

For now this is adequate, but if any one can suggest a way to remove the vacuum system on the headlight, maybe I could try and repair it and get things back to the way intended.

Regards my observation about the many vacuum systems, it seems that the headlight and EGR is powered from and engine based pump whereas the central locking is from an electrical pump. They seem to be independent of each other.

Thanks in advance.