Hello There.....I've a 500 sel....in the instrument cluster is an "economy gauge". It would appear to be a vacuum gauge. My question is: Would a vacuum leak affect the reading of this economy gauge? Thanks.

Yes.

__________________
2007 C 230 Sport.

what if you have no vacuum leaks and the economy gauge goes up a 1/4 of the way when ideling. falls right to the bottom on decel. This started happening after my timing chain replacement, I have no idea why.

xp

__________________
1985 190E 2.3L - a constant project.

I'll bet you've got a vacuum pipe fallen off or split.

__________________
Paul Gibbons
'93 320CE
'73 Jensen Interceptor (Resting)
Giant Full Sus Mountain Bike

Well....I found a tube connector w/o a tube...I plugged it, and now I've a smooth idle and a properly acting economy gauge....I'm begining to think that this vacuum issue is mucho importante..

Guys,
What would be the effect on the economy gauge if a fuel injector holder was cracked or a little loose or the underlying o-ring developed a small hole? Would this be considered a vacuum leak? Would it register on the gauge since no hose is involved? Or would it just create a rough idle?
Rich

I'm not sure if the gauge would pick up a very, very small leak. Most vacuum gauges are dampened ( orificed ), to even out intake pulse waves.
If a defective o-ring was suspected, I'd spray a little carb. cleaner around the area, with the engine idling.
You may also see the affected sparkplug ( on that cylinder ),with a slightly different colour pattern, than the rest of them.

__________________
2007 C 230 Sport.

Thanks Guys for your interesting threadid.

In many threadid before say that the optimal vaccum pressure is 20 inch of water column, Please, How to increase the vaccum pressure from 15 in.water to 20 in w.


Thanks

Mario Farias

__________________
MB LOVER

and if I have no vacuum leaks and my economy gauge goes all the way to the bottom when decelerating but goes back up when the car starts ideling, what would that mean?

I should probably change the rubber injector seals, and idle control vavle hoses as well.

xp

__________________
1985 190E 2.3L - a constant project.